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diff --git a/doc/kde_app_devel/index.docbook b/doc/kde_app_devel/index.docbook new file mode 100644 index 00000000..5b721135 --- /dev/null +++ b/doc/kde_app_devel/index.docbook @@ -0,0 +1,1549 @@ +<?xml version="1.0" ?> +<!DOCTYPE book PUBLIC "-//KDE//DTD DocBook XML V4.1.2-Based Variant V1.1//EN" "dtd/kdex.dtd" [ + <!ENTITY kdevelop "<application>KDevelop</application>"> + <!ENTITY kappname "&kdevelop;"> + <!ENTITY % addindex "INCLUDE"> + <!ENTITY % English "INCLUDE" > <!-- change language only here --> +]> + +<book lang="&language;"> + +<bookinfo> +<title>The &kdevelop; Programming Handbook</title> + +<date>2002-12-05</date> +<releaseinfo>2.0</releaseinfo> + +<authorgroup> +<author> +<firstname>Ralf</firstname> +<surname>Nolden</surname> +<affiliation><address><email>Ralf.Nolden@post.rwth-aachen.de</email></address></affiliation> +</author> +<author> +<firstname>Caleb</firstname> +<surname>Tennis</surname> +<affiliation><address><email>caleb@aei-tech.com</email></address></affiliation> +</author> +</authorgroup> + +<copyright> +<year>1999</year> +<holder>Ralf Nolden</holder> +</copyright> +<copyright> +<year>2002</year> +<holder>Caleb Tennis</holder> +</copyright> + +<!-- ROLES_OF_TRANSLATORS --> + +<legalnotice>&FDLNotice;</legalnotice> + +<abstract> +<para>The User Guide to C++ Application Design for the K Desktop Environment (KDE) with +the &kdevelop; IDE</para> +</abstract> + +<keywordset> +<keyword>KDE</keyword> +<keyword>KDevelop</keyword> +<keyword>IDE</keyword> +<keyword>development</keyword> +<keyword>programming</keyword> +</keywordset> + +</bookinfo> + +<chapter id="chapter1"> +<title>Introduction</title> +<para> +As Unix Systems are becoming more and more popular to even beginners working with computer machines +due to its advantages in regards of stability and functionality, most are somehow disappointed, because +those applications don't have a consistent look and each one behaves different from another. With KDE, +developers have an almost perfect way to create first-class applications for Unix desktop systems to get +a wider user community by the mere quality their applications have to offer. Therefore, KDE becomes more +and more popular as a base for programming design, and developers want to take advantage of the +possibilities that the system has to offer. +</para> + +<sect1 id="c1s1"> +<title>What you should know already</title> +<para> +For making the best use of this programming handbook, we assume that you already know about the +C++ programming language; if not, you should make yourself familiar with that first. Information about +C++ is available through various sources either in printed form at your local bookstore or by tutorials +found on the Internet. Knowledge about the design of Graphical User Interfaces is not required, as this +handbook tries to cover the application design for KDE programs, which also includes an introduction into +the Qt toolkit as well as the KDE libraries and the design of User Interfaces. Also, you should have made +yourself comfortable with &kdevelop; by reading The User Manual to &kdevelop;, which contains a descriptive +review of the functionality provided by the IDE. +</para> +</sect1> + +<sect1 id="c1s2"> +<title>About this Handbook</title> +<para> +This handbook has been written to give developers an introduction into KDE application development by +using the KDevelop Integrated Development Environment. +</para> +<para> +The following chapters therefore give an introduction on how to create projects, explains the sourcecode +already generated and shows how to extend the given sources on various topics such as toolbars, menu bars +and view areas. +</para> +<para> +Then the dialogeditor is discussed in detail, explaining how widgets are created and covers widget +properties settings in detail for all provided widgets. +</para> +<para> +Finally, you will learn about several topics that will complete your knowledge in regards of project design +and helps you work out additional issues besides coding such as adding API documentation and extending +online-manuals. +</para> +<sect2 id="c1s2s1"> +<title>In the next chapter</title> +<para> +We'll take a look at the Qt and KDE libraries, showing basic concepts and why things are the way they are. +Also, we will discuss how to create the tutorial applications provided with the Qt toolkit by using +kdevelop;, so beginners can already see first results with a few steps, and thereby will learn how to make +use of some of &kdevelop;'s best features. +</para> +</sect2> + +<sect2 id="c1s2s2"> +<title>In the following chapters</title> +<para> +You will learn how to: +<itemizedlist> +<listitem><para>create an application with the KAppWizard</para></listitem> +<listitem><para>What the project skeleton already provides</para></listitem> +<listitem><para>What the code already create means</para></listitem> +<listitem><para>How to create your own views</para></listitem> +<listitem><para>How to extend your application's functionality by dialog, menu bars, and toolbars</para></listitem> +<listitem><para>How to make your application user friendly by providing help functions</para></listitem> +<listitem><para>How to write online documentation</para></listitem> +</itemizedlist> +</para> +</sect2> + +</sect1> + +<sect1 id="c1s3"> +<title>Additional Information</title> +<para> +Additional information about Qt/KDE programming is available by various sources: +<itemizedlist> +<listitem><para>Programming with Qt by Matthias Kalle Dalheimer</para></listitem> +<listitem><para><ulink url="www.kdevelop.org">The User Manual to KDevelop, provided with the KDevelop IDE</ulink></para></listitem> +<listitem><para><ulink url="doc.trolltech.com">The Online Reference to the Qt library</ulink></para></listitem> +<listitem><para><ulink url="developer.kde.org">The KDE Developer web site</ulink></para></listitem> +</itemizedlist> +</para> +<para> +Additionally, you should look for help by subscribing to the various mailing lists, whose addresses +are available on the mentioned web sites, and on the Usenet newsgroups dedicated to users of KDE and +Unix Systems as well as about the C and C++ programming language. +</para> +<para> +For obtaining help about the KDevelop IDE, you should send requests to our mailinglist at +<email>kdevelop@kdevelop.org</email>. Mind that the KDevelop team is dedicated to provide the means to enable you to +program applications and therefore is not intended as a technical support team in cases where the +applications you're developing don't work due to implementation errors or misconfigurations of your +operating system. By this, we ask all users to take advantage of the mailinglist in any case you're running +into problems with the use of the IDE itself, as well as for bug reports and suggestions for improving the +functionality of the development environment. +</para> +</sect1> + +</chapter> + +<chapter id="chapter2"> +<title>The KDE and Qt Libraries</title> +<para> +The Norwegian company TrollTech (<ulink url="http://www.trolltech.com">http://www.trolltech.com</ulink>) +provides a so-called GUI toolkit, named Qt. GUI means "Graphical User Interface", and therefore, Qt-based +applications represent themselves with buttons, windows etc, allowing user input by visualizing the functions +an application provides. Such a toolkit is needed for developing graphical applications that run on the X-Window +interface on Unix Systems, because X does not contain a pre-defined user interface itself. Although other +toolkits are also available to create User Interfaces, Qt offers some technical advantages that make +application design very easy. Additionally, the Qt toolkit is also available for Microsoft Windows systems, +which allows developers to provide their applications for both platforms. +</para> +<para> +The KDE Team (<ulink url="http://www.kde.org">http://www.kde.org</ulink>) joined together with the goal +to make using Unix Systems more friendly, and decided to use the Qt toolkit for the development of a window +manager on X-Windows, plus a variety of tools included with the KDE packages. The K Desktop Environment +therefore contains the window manager kwm, the file manager kfm and the launch panel kpanel as the main +components plus a variety of first-class utilities and applications. After KDE was out, a lot of developers +turned their eyes towards the new environment and what it has to offer them. The KDE libraries are providing +essential methods and classes that make all applications designed with them look similar and consistent, +so the user has the great advantage that he only has to get accustomed with an application's specific +usage, not with handling dialogs or buttons. Also, KDE programs integrate themselves into the desktop and +are able to interact with the file manager via drag'n drop, offer session management and many more, if all +features offered by the KDE libraries are used. Both, the Qt toolkit and the KDE libraries, are implemented +in the C++ programming language; therefore applications that make use of these libraries are also mostly +written in C++. In the following chapter, we'll make a short trip through the libraries to see what already +is provided and how Qt and KDE applications are created in general. +</para> +<para> +Both, the Qt toolkit and the KDE libraries, are implemented in the C++ programming language; +therefore applications that make use of these libraries are also mostly written in C++. In the following +chapter, we'll make a short trip through the libraries to see what already is provided and how Qt and KDE +applications are created in general. +</para> + +<sect1 id="c2s1"> +<title>The Qt GUI Toolkit</title> +<para> +As said, the Qt library is a toolkit that offers graphical elements that are used for creating GUI +applications and are needed for X-Window programming. Additionally, the toolkit offers: +<itemizedlist> +<listitem><para>A complete set of classes and methods ready to use even for non-graphical programming issues</para></listitem> +<listitem><para>A good solution towards user interaction by virtual methods and the signal/slot mechanism</para></listitem> +<listitem><para>A set of predefined GUI-elements, called "widgets", that can be used easily for creating the visible elements</para></listitem> +<listitem><para>Additional completely pre-defined dialogs that are often used in applications such as progress and file dialogs</para></listitem> +</itemizedlist> +</para> +<para> +Therefore knowing the Qt classes is very essential, even if you only want to program KDE-applications. +To have an impression on the basic concept how GUI-applications are constructed and compiled, we'll first +have a look at a sample Qt-only program; then we'll extend it to a KDE program. +</para> + +<sect2 id="c2s1s1"> +<title>The first Qt Application</title> +<para> +As usual, programs in C++ have to contain a <function>main()</function> function, which is the starting point for application +execution. As we want them to be graphically visible in windows and offering user interaction, +we first have to know, how they can show themselves to the user. For an example, we'll have a look +at the first tutorial included with the Qt Online Reference Documentation and explain the basic execution +steps; also why and how the application window appears: +<programlisting> +#include <qapplication.h> +#include <qpushbutton.h> + +int main( int argc, char **argv ) +{ +QApplication a( argc, argv ); + +QPushButton hello( "Hello world!", 0 ); +hello.resize( 100, 30 ); + +a.setMainWidget( &hello ); +hello.show(); +return a.exec(); +} +</programlisting> +</para> +<para> +This application merely paints a window containing a button with "Hello world" as its text. As for +all Qt-based applications, you first have to create an instance of the class <classname>QApplication</classname>, represented by +variable a. +</para> +<para> +Next, the program creates an instance of the class <classname>QPushButton</classname> called hello, this will be the button. +The constructor of hello gets a string as a parameter, which is the contents of the widget visible as +the buttons text. +</para> +<para> +Then the <methodname>resize()</methodname> method is called on the hello button. This changes the default size a widget +(which is in this case the <classname>QPushButton</classname>) has when created to the length of 100 pixels and the height of +30 pixels. Finally, the setMainWidget() method is called for a and the show() method for hello. The +QApplication is finally executed by <methodname>a.exec()</methodname>, enters the main event loop and waits until it has to return +an integer value to the overlaying Operating System signaling that the application is exited. +</para> +</sect2> + +<sect2 id="c2s1s2"> +<title>The Reference Documentation for Qt</title> +<para> +Now, let's have a quick look at the reference documentation of the Qt library. To do this, start +&kdevelop; and select "Qt" from the tree in the Documentation tab. The documentation browser opens +and shows you the start page of the Qt reference. This will be your first place to get information +about Qt, it's classes and the available functions they provide. Also, the above program is the first +that is included in the tutorials section. To get to the classes we want to have a look at, +<classname>QApplication</classname> and <classname>QPushButton</classname>, select "Alphabetical Class List" +and search for the according names. Follow either of them to have a look at the class documentation. +</para> +<para> +Alternatively, you can use the online documentation from Trolltech's <ulink url="doc.trolltech.com">Qt Documentation</ulink> +</para> +<para> +For <classname>QApplication</classname>, you will see the constructor and all other methods that this +class provides. If you follow a link, you will get more information about the usage and meaning of the +methods, which is very useful when you sometimes can't detect the correct use or want to have an example. +This also counts for the KDE library documentation, which uses a similar documentation type; therefore +this is almost all you have to know about using the class-references with the documentation browser. +</para> +<sect3 id="c2s1s2s1"> +<title>Interpretation of the Sample</title> +<para> +Starting with <classname>QApplication</classname>, you will find all the methods used in our first example: +<itemizedlist> +<listitem><para>the constructor <methodname>QApplication()</methodname></para></listitem> +<listitem><para>the <methodname>setMainWidget()</methodname> method</para></listitem> +<listitem><para>the <methodname>exec()</methodname> method</para></listitem> +</itemizedlist> +</para> +<para> +The interpretation why we use these methods is very simple: +<orderedlist> +<listitem><para>Create an instance of the class <classname>QApplication</classname> with the constructor, +so we can make use of the GUI elements provided by Qt</para></listitem> +<listitem><para>Create a widget which will be the contents of our program window</para></listitem> +<listitem><para>Set the widget as the main widget for a</para></listitem> +<listitem><para>Execute the a instance of <classname>QApplication</classname></para></listitem> +</orderedlist> +</para> +<para> +The second object of our program is the pushbutton, an instance of the class <classname>QPushButton</classname>. +From the two constructors given to create an instance, we used the second: this accepts a text, +which is the label contents of the button; here, it is the string "Hello world!". Then we called the +<methodname>resize()</methodname> method to change the size of the button according to it's contents - +the button has to be larger to make the string completely visible. +</para> +<para> +But what about the <methodname>show()</methodname> method? Now, you see that like most other widgets, +<classname>QPushButton</classname> is based on a single inheritance, the documentation says, Inherits +<classname>QButton</classname>. Follow the link to the <classname>QButton</classname> class. +This shows you a lot of other widgets that are inherited by <classname>QPushButton</classname>, +which we'll use later to explain the signal/slot mechanism. Anyway, the <methodname>show()</methodname> +method is not listed, therefore, it must be a method that is provided by inheritance as well. The class +that <classname>QButton</classname> inherits is <classname>QWidget</classname>. Just follow the link +again, and you will see a whole bunch of methods that the QWidget class provides; including +the <methodname>show()</methodname> method. Now we understand what was done in the sample with the button: +<orderedlist> +<listitem><para>Create an instance of <classname>QPushButton</classname>, use the second constructor to set the button text</para></listitem> +<listitem><para>Resize the widget to its contents</para></listitem> +<listitem><para>Set the widget as the main widget of the <classname>QApplication</classname> instance a</para></listitem> +<listitem><para>Tell the widget to display itself on the screen by calling <methodname>show()</methodname>, an inherited method from <classname>QWidget</classname></para></listitem> +</orderedlist> +</para> +<para> +After calling the <methodname>exec()</methodname> method, the application is visible to the user, +showing a window with the button showing "Hello world!". Note: GUI programs behave somewhat differently +than procedural applications. The main thing here is that the application enters a so-called +"main event loop". This means that the program has to wait for user actions and then react to it, also +that for a Qt application, the program has to be in the main event loop to start the event handling. +The next section tells you in short what this means to the programmer and what Qt offers to process +user events. +</para> +<note><para> +For already advanced users: The button has no parent declared in the constructor, therefore it +is a top-level widget alone and runs in a local event loop which doesn't need to wait for the main +event loop. See the QWidget class documentation and The KDE Library Reference Guide</para> +</note> + +</sect3> +</sect2> + +<sect2 id="c2s1s3"> +<title>User Interaction</title> +<para> +After reading the last sections, you should already know: +<itemizedlist> +<listitem><para>What the Qt-library provides in terms of GUI applications</para></listitem> +<listitem><para>How a program using Qt is created and</para></listitem> +<listitem><para>Where and how to find information about classes that you want to use with the documentation browser</para></listitem> +</itemizedlist> +</para> +<para> +Now we'll turn to give the application "life" by processing user events. Generally, the user has two ways +to interact with a program: the mouse and the keyboard. For both ways, a graphical user interface has to +provide methods that detect actions and methods that do something as a reaction to these actions. +</para> +<para> +The Window system therefore sends all interaction events to the according application. The +<classname>QApplication</classname> then sends them to the active window as a <classname>QEvent</classname> +and the widgets themselves have to decide what to do with them. A widget receives the event and processes +<methodname>QWidget::event(QEvent*)</methodname>, which then decides which event has been executed +and how to react; <methodname>event()</methodname> is therefore the main event handler. Then, +the <methodname>event()</methodname> method passes the event to so-called event filters +that determine what happened and what to do with the event. If no filter signs responsible for the +event, the specialized event handlers are called. Thereby we can decide between: +<itemizedlist> +<listitem><para> +Keyboard events -- TAB and Shift-TAB keys:</para> +<itemizedlist> +<listitem><para><methodname>virtual void focusInEvent(QFocusEvent *)</methodname></para></listitem> +<listitem><para><methodname>virtual void focusOutEvent(QFocusEvent *)</methodname></para></listitem> +</itemizedlist> +</listitem> + +<listitem><para> +All other keyboard input:</para> +<itemizedlist> +<listitem><para><methodname>virtual void keyPressEvent(QKeyEvent *)</methodname></para></listitem> +<listitem><para><methodname>virtual void keyReleaseEvent(QKeyEvent *)</methodname></para></listitem> +</itemizedlist> +</listitem> + +<listitem><para> +Mouse movements:</para> +<itemizedlist> +<listitem><para><methodname>virtual void mouseMoveEvent(QMouseEvent *)</methodname></para></listitem> +<listitem><para><methodname>virtual void enterEvent(QEvent *)</methodname></para></listitem> +<listitem><para><methodname>virtual void leaveEvent(QEvent *)</methodname></para></listitem> +</itemizedlist> +</listitem> + +<listitem><para> +Mouse button actions</para> +<itemizedlist> +<listitem><para><methodname>virtual void mousePressEvent(QMouseEvent *)</methodname></para></listitem> +<listitem><para><methodname>virtual void mouseReleaseEvent(QMouseEvent *)</methodname></para></listitem> +<listitem><para><methodname>virtual void mouseDoubleClickEvent(QMouseEvent *)</methodname></para></listitem> +</itemizedlist> +</listitem> + +<listitem><para> +Window events containing the widget</para> +<itemizedlist> +<listitem><para><methodname>virtual void moveEvent(QMoveEvent *)</methodname></para></listitem> +<listitem><para><methodname>virtual void resizeEvent(QResizeEvent *)</methodname></para></listitem> +<listitem><para><methodname>virtual void closeEvent(QCloseEvent *)</methodname></para></listitem> +</itemizedlist> +</listitem> + +</itemizedlist> +</para> +<para> +Note that all event functions are virtual and protected; therefore you can re-implement the events +that you need in your own widgets and specify how your widget has to react. <classname>QWidget</classname> +also contains some other virtual methods that can be useful in your programs; anyway, it is sufficient +to know about <classname>QWidget</classname> very well. +</para> +</sect2> +<sect2 id="c1s2s4"> +<title>Object Interaction by Signals and Slots</title> +<para> +Now we're coming to the most obvious advantages of the Qt toolkit: the signal/slot mechanism. +This offers a very handy and useful solution to object interaction, which usually is solved by +callback functions for X-Window toolkits. As this communication requires a strict programming and +sometimes makes user interface creation very difficult (as referred by the Qt documentation and explained +in Programming with Qt by K.Dalheimer), Troll Tech invented a new system where objects can emit signals +that can be connected to methods declared as slots. For the C++ part of the programmer, he only has to know +some things about this mechanism: +<itemizedlist> +<listitem><para> +the class declaration of a class using signals/slots has to contain the Q_OBJECT macro at the beginning +(without a semicolon); and have to be derved from the <classname>QObject</classname> class +</para></listitem> +<listitem><para> +a signal can be emitted by the keyword emit, e.g. emit signal(parameters); from within any member function +of a class that allows signals/slots +</para></listitem> + +<listitem><para> +all signals used by the classes that are not inherited have to be added to the class declaration by a +signals section +</para></listitem> +<listitem><para> +all methods that can be connected with a signal are declared in sections with the additional keyword slot, +e.g. public slots: within the class declaration +</para></listitem> +<listitem><para> +the meta-object compiler moc has to run over the header file to expand the macros and to produce the +implementation (which is not necessary to know). The output files of moc are compiled also by the C++ compiler. +</para></listitem> +</itemizedlist> +</para> +<para> +Another way to use signals without deriving from <classname>QObject</classname> is to use the +<classname>QSignal</classname> class- see the reference documentation for more information and example +usage. In the following, we assume you're deriving from <classname>QObject</classname>. +</para> +<para> +This way, your class is able to send signals anywhere and to provide slots that signals can connect +to. By using the signals, you don't have to care about who's receiving it- you just have to emit the +signal and whatever slot you want to connect to it can react to the emission. Also the slots can be used +as normal methods during implementation. +</para> +<para> +Now, to connect a signal to a slot, you have to use the <methodname>connect()</methodname> methods that +are provided by <classname>QObject</classname> or, where available, special methods that objects provide +to set the connection for a certain signal. +</para> + +<sect3 id="c1s2s4s1"> +<title>Sample Usage</title> +<para> +To explain the way how to set up object-interaction, we'll take our first example again and extend it by a +simple connection: +<programlisting> +#include <qapplication.h> +#include <qpushbutton.h> + +int main( int argc, char **argv ) +{ +QApplication a( argc, argv ); + +QPushButton hello( "Hello world!" , 0); +hello.resize( 100, 30 ); + +a.setMainWidget( &hello ); + +QObject::connect(&hello, SIGNAL( clicked() ), &a, SLOT( quit() )); + +hello.show(); +return a.exec(); +} +</programlisting> +</para> +<para> +You see, the only addition to give the button more interaction is to use a <methodname>connect() +</methodname> method: <methodname>connect(&hello, SIGNAL( clicked() ), &a, SLOT( quit() ))</methodname>; +is all you have to add. What is the meaning now? The class declaration of QObject says about the +<methodname>connect()</methodname> method: +</para> +<para><methodname> +bool connect ( const QObject * sender, const char * signal, const QObject * receiver, const char * member ) +</methodname></para> +<para> +This means you have to specify a <classname>QObject</classname> instance pointer that is the sender +of the signal, meaning that it can emit this signal as first parameter; then you have to specify the signal +that you want to connect to. The last two parameters are the receiver object that provides a slot, followed +by the member function which actually is the slot that will be executed on signal emission. +</para> +<para> +By using signals and slots, your program's objects can interact with each other easily without explicitly +depending on the type of the receiver object. You will learn more about using this mechanism for productive +usage later in this handbook. More information about the Signals/Slot mechanism can also be found in +<ulink url="developer.kde.org/documentation/library/libraryref.html">The KDE Library Reference Guide</ulink> +and the <ulink url="doc.trolltech.com">Qt online reference</ulink>. +</para> +</sect3> +</sect2> +</sect1> + +<sect1 id="c2s3"> +<title>What KDE provides</title> +<sect2 id="c2s3s1"> +<title>The KDE 3.x libraries</title> +<para> +The main KDE libraries you'll be using for creating your own KDE applications are: +<itemizedlist> +<listitem><para> +the kdecore library, containing all classes that are non-visible elements to provide application functionality +</para></listitem> +<listitem><para> +the kdeui library, containing user interface elements like menubars, toolbars, etc. +</para></listitem> +<listitem><para> +the kfile library, containing the file selection dialogs +</para></listitem> +</itemizedlist> +</para> +<para> +Additionally, for specific solutions KDE offers the following libraries: +<itemizedlist> +<listitem><para> +the kdefx library, containing pixmaps, image effects the KStyle extension to QStyle +</para></listitem> +<listitem><para> +the khtml library, containing KDE's html component +</para></listitem> +<listitem><para> +the kjs library, containing KDE's Javascript support +</para></listitem> +<listitem><para> +the kio library, containing low level access to network files +</para></listitem> +<listitem><para> +the kparts library, containing support for re-usable embeddable extendable applications +</para></listitem> +</itemizedlist> +</para> +<para> +Next we'll have a look at what is needed to turn out first Qt Application into a KDE one. +</para> +</sect2> +<sect2 id="c2s3s2"> +<title>Example KDE Application</title> +<para> +In the following, you will see that writing a KDE application is not much more difficult than a +Qt application. For the use of KDE's features, you just have to use some other classes, and you're almost +done. As an example, we'll discuss the changed version of the Qt example from above: +<programlisting> +#include <kapplication.h> +#include <qpushbutton.h> + +int main( int argc, char **argv ) +{ +KApplication a( argc, argv ); + +QPushButton hello( "Hello world!", 0 ); +hello.resize( 100, 30 ); + +a.setTopWidget( &hello ); + +QObject::connect(&hello, SIGNAL( clicked() ), &a, SLOT( quit() )); + +hello.show(); +return a.exec(); +} +</programlisting> +</para> +<para> +You see that first we have changed from <classname>QApplication</classname> to <classname>KApplication +</classname>. Further, we had to change the previously used <methodname>setMainWidget()</methodname> method +to <methodname>setTopWidget</methodname>, which <classname>KApplication</classname> uses to set the main +widget. That's it! Your first KDE application is ready - you only have to tell the compiler the KDE +include path and the linker to link in the kdecore library with -lkdecore. +</para> +<para> +As you now know what at least the <function>main()</function> function provides generally and how an +application gets visible and allows user and object interaction, we'll go on with the next chapter, +where our first application is made with &kdevelop;. There you can also test everything which was +mentioned before and see the effects. +</para> +<para> +What you should have looked into additionally until now is the reference documentation for Qt, +especially the <classname>QApplication</classname>, <classname>QWidget</classname> and <classname>QObject +</classname> class and the kdecore library documentation for the <classname>KApplication</classname> class. +The <ulink url="developer.kde.org/documentation/library/libraryref.html">KDE Library Reference handbook</ulink> +also covers a complete description about the invocation of the <classname>QApplication</classname> and +<classname>KApplication</classname> constructors including command-line argument processing. +</para> +</sect2> +</sect1> + +</chapter> + +<chapter id="chapter3"> +<title>Creating New Applications</title> + +<sect1 id="c3s1"> +<title>The Application Wizard</title> +<para> +&kdevelop;'s Application Wizard is intended to let you start working on new project with &kdevelop;. Therefore +all of your projects are first created by the wizard, and then you can start building them and extend what is +already provided by the source skeleton. You can choose from several project types according to your project goals: +<itemizedlist> +<listitem><para> +KDE Application Framework: includes source code for a complete frame structre of a standard KDE application +</para></listitem> +<listitem><para> +QMake Project: Creates an application framework based around Trolltech's qmake configuration system +</para></listitem> +<listitem><para> +Simple hello world program: Creates a C++ terminal based program with no GUI support +</para></listitem> +<listitem><para> +A multitude of other program skeletons +</para></listitem> +</itemizedlist> +</para> +<para> +In this chapter we'll see how the Application Wizard can be invoked and what has to be done to generate +a KDE application project. This will also be the initial step of our coverage, where we will create the +initial version of a sample project. For all other project types the steps are usualyl the same, but you +may not have as many options available. +</para> +</sect1> + +<sect1 id="c3s2"> +<title>Invoking the Application Wizard and Project Generation</title> +<sect2 id="c3s2s1"> +<title>Starting the Application Wizard and the First Page</title> +<para> +To start with your KDE application, open &kdevelop;. From the Project menu, selection New Project. The +Application Wizard starts, and you'll see the selection tree on the first page containing available project +types that can be created. Choose the C++ subtree, then KDE, then Application Framework. +</para> +<para> +For our sample project, we are going to create the application KScribble. Enter this as the application +name, and change any other information at the bottom of this screen that may need it. Then, select Next. +<screenshot><mediaobject><imageobject> +<imagedata fileref="appwizard.png" format="PNG"/> +</imageobject><textobject><phrase>Application Wizard</phrase></textobject> +</mediaobject></screenshot> +</para> +</sect2> +<sect2 id="c3s2s2"> +<title>Version control information</title> +<para> +On this screen you have the ability to decide if your project will use a version control system like +CVS. For our sample project we will not use source control, so make sure the selection box reads None +and select Next. +</para> +</sect2> +<sect2 id="c3s2s3"> +<title>Header and Source Templates</title> +<para> +The next two pages show example headers that will go at the top of each of the header and source files that +you create using &kdevelop;. For now, just leave these as the default, and select Next, then Finish. If the +Finish button is not activated, you haven't set all of the options correct. Use the Back button to return +to earlier menus and correct any mistakes. +</para> +</sect2> +<sect2 id="c3s2s4"> +<title>Finishing Up</title> +<para> +Upon completion, the Application Wizard should close and the messages window should popup displaying +information about the tasks that &kdevelop; is currently doing. At the end of all of the tasks, you +should see **** Success *****. This means the application framework was successfully loaded. +</para> +</sect2> +</sect1> + +<sect1 id="c3s3"> +<title>The First Build</title> +<para> +After our project is generated, we'll first make a trip through the source code to get a general understanding +of how the application framework looks. This won't only help us get started, but we'll know where to change +what in later steps. +</para> +<para> +This chapter makes the assumption that you understand the basic navigation of &kdevelop;. Consult the +KDevelop User Manual for information if you need it. +</para> +<para> +The Automake manager shows the project files as follows: +<screenshot><mediaobject><imageobject> +<imagedata fileref="kscribblefiles.png" format="PNG"/> +</imageobject><textobject><phrase>Files in our project</phrase></textobject> +</mediaobject></screenshot> +</para> +<para> +Before diving into the sources, we'll let &kdevelop; build an run our new application. To do this, select +Build Project from the Build menu, or press F8. The output window opens and displays output messages during +the compilation phase. +<programlisting> +1 cd /home/caleb/kscribble && WANT_AUTOCONF_2_5=1 WANT_AUTOMAKE_1_6=1 gmake k +2 gmake all-recursive +3 gmake[1]: Entering directory `/home/caleb/kscribble' +4 Making all in doc +5 gmake[2]: Entering directory `/home/caleb/kscribble/doc' +6 Making all in . +7 gmake[3]: Entering directory `/home/caleb/kscribble/doc' +8 gmake[3]: Nothing to be done for `all-am'. +9 gmake[3]: Leaving directory `/home/caleb/kscribble/doc' +10 Making all in en +11 gmake[3]: Entering directory `/home/caleb/kscribble/doc/en' +12 /usr/local/kde3/bin/meinproc --check --cache index.cache.bz2 /home/caleb/kscribble/doc/en/index.docbook +13 gmake[3]: Leaving directory `/home/caleb/kscribble/doc/en' +14 gmake[2]: Leaving directory `/home/caleb/kscribble/doc' +15 Making all in po +16 gmake[2]: Entering directory `/home/caleb/kscribble/po' +17 gmake[2]: Nothing to be done for `all'. +18 gmake[2]: Leaving directory `/home/caleb/kscribble/po' +19 Making all in src +20 gmake[2]: Entering directory `/home/caleb/kscribble/src' +21 source='main.cpp' object='main.o' libtool=no \ +22 depfile='.deps/main.Po' tmpdepfile='.deps/main.TPo' \ +23 depmode=gcc3 /bin/sh /home/caleb/kscribble/admin/depcomp \ +24 g++ -DHAVE_CONFIG_H -I. -I/home/caleb/kscribble/src -I.. -I/usr/local/kde3/include + -I/usr/lib/qt/include -I/usr/X11R6/include -DQT_THREAD_SUPPORT -D_REENTRANT -Wnon-virtual-dtor + -Wno-long-long -Wundef -Wall -pedantic -W -Wpointer-arith -Wmissing-prototypes -Wwrite-strings + -ansi -D_XOPEN_SOURCE=500 -D_BSD_SOURCE -Wcast-align -Wconversion -O2 -fno-exceptions -fno-check-new + -c -o main.o `test -f 'main.cpp' || echo '/home/caleb/kscribble/src/'`main.cpp +25 /usr/lib/qt/bin/moc /home/caleb/kscribble/src/kscribble.h -o kscribble.moc +26 source='kscribble.cpp' object='kscribble.o' libtool=no \ +27 depfile='.deps/kscribble.Po' tmpdepfile='.deps/kscribble.TPo' \ +28 depmode=gcc3 /bin/sh /home/caleb/kscribble/admin/depcomp \ +29 g++ -DHAVE_CONFIG_H -I. -I/home/caleb/kscribble/src -I.. -I/usr/local/kde3/include + -I/usr/lib/qt/include -I/usr/X11R6/include -DQT_THREAD_SUPPORT -D_REENTRANT -Wnon-virtual-dtor + -Wno-long-long -Wundef -Wall -pedantic -W -Wpointer-arith -Wmissing-prototypes -Wwrite-strings + -ansi -D_XOPEN_SOURCE=500 -D_BSD_SOURCE -Wcast-align -Wconversion -O2 -fno-exceptions -fno-check-new + -c -o kscribble.o `test -f 'kscribble.cpp' || echo '/home/caleb/kscribble/src/'`kscribble.cpp +30 kscribble.cpp: In member function `void KScribble::setupActions()' +31 kscribble.cpp:107: warning: unused variable `KAction*custom' +32 /usr/lib/qt/bin/moc /home/caleb/kscribble/src/kscribbleview.h -o kscribbleview.moc +33 source='kscribbleview.cpp' object='kscribbleview.o' libtool=no \ +34 depfile='.deps/kscribbleview.Po' tmpdepfile='.deps/kscribbleview.TPo' \ +35 depmode=gcc3 /bin/sh /home/caleb/kscribble/admin/depcomp \ +36 g++ -DHAVE_CONFIG_H -I. -I/home/caleb/kscribble/src -I.. -I/usr/local/kde3/include + -I/usr/lib/qt/include -I/usr/X11R6/include -DQT_THREAD_SUPPORT -D_REENTRANT -Wnon-virtual-dtor + -Wno-long-long -Wundef -Wall -pedantic -W -Wpointer-arith -Wmissing-prototypes -Wwrite-strings -ansi + -D_XOPEN_SOURCE=500 -D_BSD_SOURCE -Wcast-align -Wconversion -O2 -fno-exceptions -fno-check-new -c + -o kscribbleview.o `test -f 'kscribbleview.cpp' || echo '/home/caleb/kscribble/src/'`kscribbleview.cpp +37 kscribbleview.cpp: In member function `void KScribbleView::print(QPainter*, +38 int, int)': +39 kscribbleview.cpp:79: warning: unused parameter `QPainter*p' +40 kscribbleview.cpp:79: warning: unused parameter `int height' +41 kscribbleview.cpp:79: warning: unused parameter `int width' +42 /usr/lib/qt/bin/moc /home/caleb/kscribble/src/pref.h -o pref.moc +43 source='pref.cpp' object='pref.o' libtool=no \ +44 depfile='.deps/pref.Po' tmpdepfile='.deps/pref.TPo' \ +45 depmode=gcc3 /bin/sh /home/caleb/kscribble/admin/depcomp \ +46 g++ -DHAVE_CONFIG_H -I. -I/home/caleb/kscribble/src -I.. -I/usr/local/kde3/include + -I/usr/lib/qt/include -I/usr/X11R6/include -DQT_THREAD_SUPPORT -D_REENTRANT -Wnon-virtual-dtor + -Wno-long-long -Wundef -Wall -pedantic -W -Wpointer-arith -Wmissing-prototypes -Wwrite-strings + -ansi -D_XOPEN_SOURCE=500 -D_BSD_SOURCE -Wcast-align -Wconversion -O2 -fno-exceptions -fno-check-new + -c -o pref.o `test -f 'pref.cpp' || echo '/home/caleb/kscribble/src/'`pref.cpp +47 /usr/local/kde3/bin/dcopidl /home/caleb/kscribble/src/kscribbleiface.h > kscribbleiface.kidl || + ( rm -f kscribbleiface.kidl ; /bin/false ) +48 /usr/local/kde3/bin/dcopidl2cpp --c++-suffix cpp --no-signals --no-stub kscribbleiface.kidl +49 source='kscribbleiface_skel.cpp' object='kscribbleiface_skel.o' libtool=no \ +50 depfile='.deps/kscribbleiface_skel.Po' tmpdepfile='.deps/kscribbleiface_skel.TPo' \ +51 depmode=gcc3 /bin/sh /home/caleb/kscribble/admin/depcomp \ +52 g++ -DHAVE_CONFIG_H -I. -I/home/caleb/kscribble/src -I.. -I/usr/local/kde3/include + -I/usr/lib/qt/include -I/usr/X11R6/include -DQT_THREAD_SUPPORT -D_REENTRANT -Wnon-virtual-dtor + -Wno-long-long -Wundef -Wall -pedantic -W -Wpointer-arith -Wmissing-prototypes -Wwrite-strings + -ansi -D_XOPEN_SOURCE=500 -D_BSD_SOURCE -Wcast-align -Wconversion -O2 -fno-exceptions -fno-check-new + -c -o kscribbleiface_skel.o `test -f 'kscribbleiface_skel.cpp' || + echo '/home/caleb/kscribble/src/'`kscribbleiface_skel.cpp +53 /bin/sh ../libtool --silent --mode=link --tag=CXX g++ -Wnon-virtual-dtor -Wno-long-long -Wundef -Wall + -pedantic -W -Wpointer-arith -Wmissing-prototypes -Wwrite-strings -ansi -D_XOPEN_SOURCE=500 + -D_BSD_SOURCE -Wcast-align -Wconversion -O2 -fno-exceptions -fno-check-new -o kscribble -R + /usr/local/kde3/lib -R /usr/lib/qt/lib -R /usr/X11R6/lib -L/usr/X11R6/lib -L/usr/lib/qt/lib + -L/usr/local/kde3/lib main.o kscribble.o kscribbleview.o pref.o kscribbleiface_skel.o -lkio +54 source='kscribble_client.cpp' object='kscribble_client.o' libtool=no \ +55 depfile='.deps/kscribble_client.Po' tmpdepfile='.deps/kscribble_client.TPo' \ +56 depmode=gcc3 /bin/sh /home/caleb/kscribble/admin/depcomp \ +57 g++ -DHAVE_CONFIG_H -I. -I/home/caleb/kscribble/src -I.. -I/usr/local/kde3/include + -I/usr/lib/qt/include -I/usr/X11R6/include -DQT_THREAD_SUPPORT -D_REENTRANT -Wnon-virtual-dtor + -Wno-long-long -Wundef -Wall -pedantic -W -Wpointer-arith -Wmissing-prototypes -Wwrite-strings + -ansi -D_XOPEN_SOURCE=500 -D_BSD_SOURCE -Wcast-align -Wconversion -O2 -fno-exceptions -fno-check-new + -c -o kscribble_client.o `test -f 'kscribble_client.cpp' || echo + '/home/caleb/kscribble/src/'`kscribble_client.cpp +58 /bin/sh ../libtool --silent --mode=link --tag=CXX g++ -Wnon-virtual-dtor -Wno-long-long -Wundef + -Wall -pedantic -W -Wpointer-arith -Wmissing-prototypes -Wwrite-strings -ansi -D_XOPEN_SOURCE=500 + -D_BSD_SOURCE -Wcast-align -Wconversion -O2 -fno-exceptions -fno-check-new -o kscribble_client -R + /usr/local/kde3/lib -R /usr/lib/qt/lib -R /usr/X11R6/lib -L/usr/X11R6/lib -L/usr/lib/qt/lib + -L/usr/local/kde3/lib kscribble_client.o -lkdecore +59 gmake[2]: Leaving directory `/home/caleb/kscribble/src' +60 gmake[2]: Entering directory `/home/caleb/kscribble' +61 gmake[2]: Nothing to be done for `all-am'. +62 gmake[2]: Leaving directory `/home/caleb/kscribble' +63 gmake[1]: Leaving directory `/home/caleb/kscribble' +64 *** Success *** +</programlisting> +</para> +<para> +As you can see, we've put line numbers in front of each line which won't appear on your output but it makes it +easier to describe what is happening during the build. First of all, gmake works recursively. This means +that it starts from the directory it is invoked and goes into the subdirectories first, one at a time, then +returns to the directory it was started, processes it, then finishes. +</para> +<para> +Our first line of interest is 24. Notice on this line that g++, which is our C++ compiler, gets called by make +to compile the first source code file in our project - in this case main.cpp. Many extra command line options +are also being used with the g++ compiler; some of which are defaults and some of which can be configured +via &kdevelop;. +</para> +<para> +Before the next file (kscribble.cpp, line 29) is compiled, the moc (meta object compiler) is first +invoked on kscribble.h (line 25). This is because KScribble classes use signals/slots, so the +Q_OBJECT macro must be expanded, and the moc does this for us. The resultant file, kscribble.moc, is +used by kscribble.cpp via an #include statement inside of the file. +</para> +</sect1> + +<sect1 id="c3s4"> +<title>The source skeleton</title> +<para> +To conceptualize how a KDE application works, we'll first have a very close look at the source +skeleton already provided by the Application Wizard. As we already saw, we're having a set of source +and header files that build the initial code for the application and make it ready-to-run. Therefore, +the easiest way to explain the code is to follow the implementation line by line as it is processed +during executing the program until it enters the main event loop and is ready to accept user input. +Then, we'll have a look at the functionality that enables user interaction and how certain things work. +This is probably the best way to explain the framework and, as it is similar to almost all KDE +applications, will enable you to read source codes from other projects as well; additionally, you will +know where to change what part of the code to make your applications behave the way they are designed for. +</para> + +<sect2 id="c3s4s1"> +<title>The main() function</title> +<para> +As the application begins its execution with entering the <function>main()</function> function, +this will be the start for our code examination. The <function>main()</function> function of +KScribble is implemented in the file main.cpp and can also be found using the Class Browser +by selecting the "Global Functions" folder. +<programlisting> +1 int main(int argc, char **argv) +2 { +3 KAboutData about("kscribble", I18N_NOOP("KScribble"), version, description, +4 KAboutData::License_GPL, "(C) 2002 Your Name", 0, 0, "you@you.com"); +5 about.addAuthor( "Your Name", 0, "you@you.com" ); +6 KCmdLineArgs::init(argc, argv, &about); +7 KCmdLineArgs::addCmdLineOptions(options); +8 KApplication app; +9 +10 // register ourselves as a dcop client +11 app.dcopClient()->registerAs(app.name(), false); +12 +13 // see if we are starting with session management +14 if (app.isRestored()) +15 RESTORE(KScribble) +16 else +17 { +18 // no session.. just start up normally +19 KCmdLineArgs *args = KCmdLineArgs::parsedArgs(); +20 if (args->count() == 0) +21 { +22 KScribble *widget = new KScribble; +23 widget->show(); +24 } +25 else +26 { +27 int i = 0; +28 for (; i < args->count(); i++) +29 { +30 KScribble *widget = new KScribble; +31 widget->show(); +32 widget->load(args->url(i)); +33 } +34 } +35 args->clear(); +36 } +37 +38 return app.exec(); +39 } +</programlisting> +</para> +<para> +Now, what happens first is the usual creation of a <classname>KApplication</classname> object, but we've +added some KDE methods that set program and author information for this application. +</para> +</sect2> +<sect2> +<title>User Application Start</title> + +<para>... (not written yet)</para> + +</sect2> +<sect2> +<title>The Constructor</title> +<para> +Let's have a look at the constructor and see how this instance is called +<programlisting> +1 KScribble::KScribble() +2 : KMainWindow( 0, "KScribble" ), +3 m_view(new KScribbleView(this)), +4 m_printer(0) +5 { +6 // accept dnd +7 setAcceptDrops(true); +8 +9 // tell the KMainWindow that this is indeed the main widget +10 setCentralWidget(m_view); +11 +12 // then, setup our actions +13 setupActions(); +14 +15 // and a status bar +16 statusBar()->show(); +17 +18 // allow the view to change the statusbar and caption +19 connect(m_view, SIGNAL(signalChangeStatusbar(const QString&)), +20 this, SLOT(changeStatusbar(const QString&))); +21 connect(m_view, SIGNAL(signalChangeCaption(const QString&)), +22 this, SLOT(changeCaption(const QString&))); +23 +24 } +</programlisting> +</para> +<para> +Notice that <classname>KScribble</classname> inherits the <classname>KMainWindow</classname> class - a +commonly used base class for KDE applications. We initialize a class called <classname>KScribbleView</classname> +as our central widget, create a <classname>KStatusBar</classname> via the <methodname>statusBar()</methodname> +method (line 16), and connect some signals and slots together. +</para> +</sect2> +</sect1> +</chapter> + + +<chapter id="chapter4"> +<title>Application View Design</title> +<sect1 id="c4s1"> +<title>Introduction</title> +<para> +When developing an application with a graphical user interface, the main work takes place in +providing a so-called "view" for the application. A view generally is a widget that displays the data +of a document and provides methods to manipulate the document contents. This can be done by the user via +the events he emits by the keyboard or the mouse; more complex operations are often processed by toolbars +and menubars which interact with the view and the document. The statusbar then provides information about +the document, view or application status. As an example, we look at how an editor is constructed and where +we can find which part. +</para> +<para> +An editor generally is supposed to provide an interface to view and/or change the contents of a text +document for the user. If you start Kate, you see the visual interface as the following: +<itemizedlist> +<listitem><para> +The menubar: providing complex operations as well as opening, saving and closing files and +exiting the application. +</para></listitem> +<listitem><para> +The toolbar: offers icons which allow quicker access for most needed functions, +</para></listitem> +<listitem><para> +The statusbar: displays the status of the cursor position by the current row and column, +</para></listitem> +<listitem><para> +The view in the center of the window, displaying a document and offering a cursor connected to +the keyboard and the mouse to operate on the data. +</para></listitem> +</itemizedlist> +</para> +<para> +Now it's easy to understand that a view is the most unique part of the application and the design +of the view decides about the usability and acceptability of an application. This means that one of +the first steps in development is to determine the purpose of the application and what kind of view +design would match best to allow any user to work with the application with a minimum of work +learning how to handle the user interface. +</para> +<para> +For some purposes like text editing and displaying HTML files, views are provided by the Qt and KDE +libraries; we will discuss certain aspects of these high-level widgets in the next section. +But for most applications new widgets have to be designed and implemented. It is that what makes a +programmer also a designer and where his abilities on creativity are asked. Nevertheless, you should +watch for intuitivity first. Remember, a lot of users won't accept an application that isn't: +<itemizedlist> +<listitem><para> +graphically nice. +</para></listitem> +<listitem><para> +offering a lot of features +</para></listitem> +<listitem><para> +easy to handle +</para></listitem> +<listitem><para> +fast to learn how to use it +</para></listitem> +</itemizedlist> +</para> +<para> +Needless to say that stability is a major design goal. Nobody can prevent bugs, but a minimum can +be reached at least by clever design goals and wide use of object-oriented design. C++ makes programming +a joy if you know how to exploit it's capabilities- inheritance, information hiding and reusablitity of +already existing code. +</para> +<para> +When creating a KDE or Qt project, you always have to have a view that inherits QWidget, either by +direct inheritance or because the library widget you want to use inherits QWidget. Therefore, the +Application Wizard already constructed a view that is an instance of a class yourappView, which +inherits QWidget already. +</para> +<para> +This chapter therefore describes how to use library widgets for creating views of KDE or +Qt applications that are generated with &kdevelop;, then we look at the libraries and what kind of +views are already offered. +</para> +</sect1> +<sect1 id="c4s2"> +<title>Using Library Views</title> +<para> +When your application design has been set up, you first should look for already existing code that +will make your life a lot easier. A part of this search is to look for a widget that can be used as +a view or at least as a part of it; either directly or by inheritance. The KDE and Qt libraries already +contain a set of widgets that can be used for this purpose. To use them, you have two options: +<orderedlist> +<listitem><para> +Remove the new view class and create an instance of a library widget; then set this as the view, +</para></listitem> +<listitem><para> +Change the inheritance of the provided view class to the class of the library widget to use. +</para></listitem> +</orderedlist> +</para> +<para> +In either way, it is important to know that if the application framework is currently not linked +against the library that contains the widget, the linker will fail. After you decided to use a +certain widget, look for the library to link to; then open "Project"->"Options" from the &kdevelop; +menubar. Switch to the "Linker Options" page and look for the checkmarks indicating the libraries +that are currently used. If the library of your view widget is already checked, you can leave the +project options untouched and start doing the necessary changes due to your choice. If not, and the +linker options offer to add the library by a check box, check it and press "OK" to leave the project +options dialog again. In any other case, add the library in the edit line below with the -l option. +For libraries that your application has to search for before preparing the Makefiles by the +configure script on the end-user machine, add the according search macro to the configure.in file +located at the root directory of your project and add the macro to the edit line. Mind that you have +to run "Build"->"Autoconf and automake" and "Build"->"Configure" before the Makefiles contain the +correct expansion for the library macro. +</para> +<para> +Also, if the include files for the library to add are not in the current include path +(which can be seen by the -I options in the output window on "Make"), you have to add the path to the +Project Options dialog -"Compiler Options" page with the -I option or the according automake macro at +the edit line for "Additional Options". +</para> +<sect2 id="c4s3s1"> +<title>Qt Views</title> +<para> +Looking at the first page of the Qt online documentation, you will find a link to +"Widget Screenshots" where you can have a look at how the widgets Qt contains look like. +These are ready to use and can be combined together to form complex widgets to create application +views or dialogs. In the following, we'll discuss some of these which are very usable for creating +application views, but keep in mind that the KDE libraries sometimes contain other widgets for the +same purpose; those will be reviewed in the next section. +</para> +<para> +Here are a set of hints for what purpose you could use which Qt component: +<orderedlist> +<listitem><para> +If your view area isn't big enough to display all your data, the user must be enabled to scroll +over the document with bars on the left and bottom of the view. For this, Qt provides the class +<classname>QScrollView</classname>, which offers a scrollable child area. As explained, you could +inherit your own widget from <classname>QScrollView</classname> or use an instance to manage your +document's view widget. +</para></listitem> +<listitem><para> +to create a ScrollView yourself, inherit the View widget from <classname>QWidget</classname> +and add vertical and horizontal <classname>QScrollBars </classname>. +(This is done by KDE`s KHTMLView widget.) +</para></listitem> +<listitem><para> +For text processing, use <classname>QTextEdit</classname>. This class provides a complete +text editor widget that is already capable to cut, copy and paste text and is managed by a scrollview. +</para></listitem> +<listitem><para> +Use <classname>QTable</classname> to display data that is arranged in a table. +As <classname>QTable</classname> is managed by scrollbars as well, it offers a good solution for +table calculation applications. +</para></listitem> +<listitem><para> +To display two different widgets or two widget instances at the same time, use <classname>QSplitter +</classname>. This allows to tile views by horizontal or vertical dividers. +KMail is a good example what this would look like- the main view is separated by a +splitter vertically, the right window then is divided again horizontally. +</para></listitem> +<listitem><para> +<classname>QListView</classname> displays information in a list and tree. +This is useful for creating file trees or any other hierarchical information you want to interact with. +</para></listitem> +</orderedlist> +</para> +<para> +You see that Qt alone offers a whole set of widgets which are ready to use so you don't have to invent +new solutions if these match your needs. The sideffect when using standard widgets is that users already +know how to handle them and only have to concentrate on the displayed data. +</para> +</sect2> +<sect2 id="c4s3s2"> +<title>KDE Views</title> +<para> +The KDE libraries were invented to make designing applications for the K Desktop Environment easier +and capable of more functionality than what Qt alone is offering. The kdeui library offers: +<orderedlist> +<listitem><para> +KListView: a more powerful version of <classname>QListView</classname> +</para></listitem> +<listitem><para> +KIconView: a graphical viewer of icon files +</para></listitem> +</orderedlist> +</para> +<para> +The khtml library, on the other hand, offers a complete HTML-interpreting widget that is ready to use. +It is scrollable already, so you don't even have to take care for that. A possible use could be to +integrate it as a preview widget for an HTML editor; used by applications such as Konqueror to display HTML files. +</para> +</sect2> +</sect1> +<sect1 id="c4s4"> +<title>Creating your own Views</title> +<para> +Not yet written +</para> +</sect1> +</chapter> + +<chapter id="chapter5"> +<title>Configuring Menubars and Toolbars</title> +<sect1 id="c5s1"> +<title>Introduction</title> +<para> +Menubars and toolbars are one of the most important parts of an application to provide methods to +work with a document structure. As a general rule, you should make all functions available by the menubar. +Those methods that should not be available at a current stage of the application process should be +disabled. +</para> +<para> +Further, an application can only contain one menubar, but several toolbars. +Toolbars on the other hand should contain only the most frequently used commands by pixmap +icons or provide quick access methods like combos to select values. +</para> +</sect1> +<sect1 id="c5s2"> +<title>How does it work?</title> +<para> +Our application inherits the <classname>KMainWindow</classname> class, which automatically handles creating +a menu bar and tool bars for us. In the <methodname>KScribble::setupActions()</methodname> method there is +a call to <methodname>KMainWindow::createGUI()</methodname>. This method loads a resource file, in this +case kscribbleui.rc, to initialize menus at startup. Note that kscribbleui.rc is listed as one of the +project files in the Automake Manager. Opening that file up reveals this: +<programlisting> +1 <!DOCTYPE kpartgui SYSTEM "kpartgui.dtd"> +2 <kpartgui name="kscribble" version="1"> +3 <MenuBar> +4 <Menu name="custom"><text>C&ustom</text> +5 <Action name="custom_action" /> +6 </Menu> +7 </MenuBar> +8 </kpartgui> +</programlisting> +</para> +<para> +Explanation... +</para> +<para> +Another way to modify the contents of the menu and tool bars is to directly manipulate them through the +methods provided by their class. For example, the <methodname>menuBar()</methodname> method returns the +<classname>KMenuBar</classname> widget that the menubar for our program. Looking at the documentation for +<classname>KMenuBar</classname> and its inheritor class <classname>QMenuBar</classname>, you will find +a large number of <methodname>insertItem()</methodname> methods which allow you to add items to the +menu bar. +</para> +<para> +<classname>KMainWindow</classname>'s methods <methodname>statusBar()</methodname> and <methodname> +toolBar()</methodname> will also provide you with applicable widgets. +</para> +</sect1> +<sect1 id="c5s3"> +<title>Keyboard Accelerator Configuration</title> +<para> +A very professional thing you should always add to your application are keyboard accelerators. +Those are mainly used by experienced users that want to work fast with their applications and +are willing to learn shortcuts. For this, the KDE libraries provide the class <classname> +KAction</classname>, which provides the keyboard accelerator keys and access to global configured +standard keyboard accelerators. +</para> +<para> +By default, frame applications generated by &kdevelop; only use standard keyboard accelerators +such as F1 for accessing online-help, Ctrl+N for New File etc. +</para> +<para> +If your application contains a lot of accelerators, you should make them configurable +by an Options-menu; either it could be combined with other application configuration in a QWidget +or stand alone. The KDE library already provides a <classname>KKeyChooser</classname> +for use in tab dialogs, whereas <classname>KKeyDialog</classname> provides a ready-to use +key-configuration dialog. +</para> + +</sect1> +</chapter> + +<!-- +<chapter id="chapter6"> +<title>Other Features</title> +</chapter> + +<chapter id="chapter7"> +<title>Printing Support</title> +</chapter> +--> +<chapter id="chapter8"> +<title>Help Functions</title> +<sect1 id="c8s1"> +<title>Introduction</title> +<para> +A very important part of the development process is to provide help functionality to the user +wherever possible. Most developers tend to delay this, but you should remember that a normal user +isn't necessarily a Unix expert. He may come from the the dark side of computer software usage offering +all sweets that a user may need to work himself into using an application even without ever touching the +manuals. Therefore, the KDE and Qt library provide all means usually considered making an application +professional in the eyes of the normal user by help functions that are ready to use. +Within the application, those are:</para> +<itemizedlist> +<listitem><para>Tool-Tips</para></listitem> +<listitem><para>Statusbar help</para></listitem> +<listitem><para>What's this...? buttons</para></listitem> +</itemizedlist> +<para> +Additionally, the application should provide means to access a HTML-based online manual directly +using the standard help key F1. This context based help system is provided automatically through the +<classname>KMainWindow</classname> class, though as the author you must provide the content. +</para> +<para> +As &kdevelop; also offers all types of help as well as the KDE framework generated by the +application wizard already contains support for this, this chapter will help you find out where +and how to add your help functionality. </para> +<para> +During the development of your application you should try to be consistent whatever you're doing; +therefore you should do the necessary steps directly while extending the code. This will prevent you +from diving into the code again and figuring out what your application does or what you intended by +certain parts of the code. +</para> +</sect1> + +<sect1 id="c8s2"> +<title>Tool-Tips</title> +<para> +A very easy means of providing help are tool-tips. Those are small help messages popping up while +the user moves the mouse over a widget that provides a tool-tip and disappears when the mouse moves away. +The most popular usage of tool-tips is made in toolbars where your tool-tips should be kept as small +as possible because toolbars can be configured to display their contents in various ways: +either displaying the button, button with text on the right, button with text below, text only. +This possibility should be made configurable by the user, but isn't a must-be. The text is shown +as a tool-tip anyway and a toolbar usually consists of buttons and other widgets like lineedits and +combo boxes. For a complete reference, see the <classname>KToolBar</classname> class reference located +in the kdeui library. +</para> +<para> +As an example, we have a look at the "New File" button in a generic application: +</para> +<para> +There, the part i18n("New File") provides a tool-tip message. It is enclosed by the i18n() +macro provided by kapp.h to translate the tool-tip towards the currently selected language. +</para> +<para> +Tool-tips can also be added to any custom widget by using the <classname>QToolTip</classname> +provided by Qt. An example of that would be: +</para> +</sect1> +<sect1 id="c8s3"> +<title>Extending the Statusbar</title> +<para> +As the applications that inherit <classname>KMainWindow</classname> contain a statusbar as well, +it also offers a set of statusbar messages already for all menu and toolbar items. A statusbar +help message is a short message that extends the meaning of a tool-tip or can be seen as a replacement +for a tool-tip over menubar items and is (as the name suggests) displayed in the statusbar when the user +enters a menu and highlights the menu entry. +</para> +</sect1> +<sect1 id="c8s4"> +<title>The <guibutton>What's This...?</guibutton> Button</title> +<para> +The <guibutton>What's This...?</guibutton> button provides help windows with the intention +that the user wants to get help about a certain widget within the working view or a toolbar item. +It is placed in the toolbar and gets activated once the user hits the button. The cursor changes +to an arrow cursor with a question mark like the button itself looks like. The the user can press on +a visible widget item and gets a help window. As an exercise, you could try this behavior with the +<guibutton>What's this...?</guibutton> button within &kdevelop;. +</para> +<para> +To add the What's This...? help to one of your widgets, use the static method +<methodname>QWhatsThis::add(QWidget *widget, const QString &text)</methodname> +</para> +</sect1> +</chapter> + +<chapter id="chapter9"> +<title>Documentation</title> +<sect1 id="c9s1"> +<title>Introduction</title> +<para> +Due to the fact that projects often lack a complete set of user documentation, +all &kdevelop; projects contain a pre-build handbook that can be easily adapted; +therefore fulfiling another goal of KDE: providing enough online-help to support users that +are not familiar with an application. This chapter therefore introduces you on how to extend +the provided documentation template and what you have to do to make it available to the user. +</para> +</sect1> +<sect1 id="c9s2"> +<title>User Documentation</title> +<para> +The documentation for your project lies in projectdir/doc/en, or perhaps another directory if English +isn't your native language. Therein lies a file, index.docbook, in which the documentation is stored. +The format for editing this file is explained on +<ulink url="http://i18n.kde.org/doc/markup/">KDE's documentation website</ulink>. +</para> +</sect1> +<sect1 id="c9s3"> +<title>Programmer Documentation</title> +<para> +Another important part of the documentation is including a descriptive help for your class interfaces. +This will allow you and other programmers to use your classes by reading the HTML class documentation +that can be created with KDoc. &kdevelop; supports the use of KDoc completely by creating the +KDE-library documentation, also your application frameworks are already documented. To work yourself +into the provided code, it would be a good start to read the included documentation online. +The following describes what to do to get the API documentation, where &kdevelop; helps you add it +and what kind of special tags KDoc provides. +</para> +</sect1> +</chapter> + +<chapter id="chapter10"> +<title>Internationalization</title> +<sect1 id="c10s1"> +<title>Introdction</title> +<para> +i18n is an internationalization system that is used to offer internationalized versions of an +application or project. The difficulty with writing applications is that they only support the +language they originally are composed with; visually this can be seen on labels, menu entries and the +like. The goal of the internationalization is to provide applications and library functions in the +language of the user; therefore enabling users that are not native speakers the original language to make +use of the provided functionality and feel more comfortable. +</para> +</sect1> +<!-- +<sect1 id="c10s2"> +<title>How KDE support Internationalization</title> +<para> +</para> +</sect1> --> +</chapter> +<!-- +<chapter id="chapter11"> +<title>Finding Errors</title> +</chapter> + +<chapter id="chapter12"> +<title>Licensing</title> +</chapter> + +<chapter id="chapter13"> +<title>References</title> +</chapter> +--> +<chapter id="credits"> +<title>Credits</title> + +<para> +(... to be written ...) +</para> + +<!--CREDITS_FOR_TRANSLATORS--> + +</chapter> <!-- credits --> + +<appendix id="bibliography"> +<title>Bibliography</title> +<bibliography> + +<biblioentry> +<title><ulink url="info://make/Top">GNU Make Manual</ulink></title> +<authorgroup> +<author><firstname>Richard M.</firstname><surname>Stallman</surname></author> +<author><firstname>Roland</firstname><surname>McGrath</surname></author> +</authorgroup> +</biblioentry> + +<biblioentry> +<title><ulink url="info://automake/Top">GNU Automake</ulink></title> +<authorgroup> +<author><firstname>David</firstname><surname>MacKenzie</surname></author> +<author><firstname>Tom</firstname><surname>Tromey</surname></author> +</authorgroup> +</biblioentry> + +<biblioentry> +<title><ulink url="info://autoconf/Top">GNU Autoconf</ulink></title> +<authorgroup> +<author><firstname>David</firstname><surname>MacKenzie</surname></author> +<author><firstname>Ben</firstname><surname>Elliston</surname></author> +</authorgroup> +</biblioentry> + +<biblioentry> +<title><ulink url="info://gcc/Top">Using the GNU Compiler Collection</ulink></title> +<author><firstname>Richard M.</firstname><surname>Stallman</surname></author> +</biblioentry> + +<biblioentry> +<title><ulink url="info://libtool/Top">GNU Libtool</ulink></title> +<authorgroup> +<author><firstname>Gordon</firstname><surname>Matzigkeit</surname></author> +<author><firstname>Alexandre</firstname><surname>Oliva</surname></author> +<author><firstname>Thomas</firstname><surname>Tanner</surname></author> +<author><firstname>Gary V.</firstname><surname>Vaughan</surname></author> +</authorgroup> +</biblioentry> + +<biblioentry> +<title>GNU Autoconf, Automake, and Libtool</title> +<edition>1st edition</edition> +<pubdate>October 2000</pubdate> +<authorgroup> +<author><firstname>Gary V.</firstname><surname>Vaughan</surname></author> +<author><firstname>Ben</firstname><surname>Elliston</surname></author> +<author><firstname>Tom</firstname><surname>Tromey</surname></author> +<author><firstname>Ian Lance</firstname><surname>Taylor</surname></author> +</authorgroup> +<publisher><publishername>New Riders Publishing</publishername></publisher> +<isbn>ISBN 1578701902</isbn> +</biblioentry> + + +<biblioentry> +<title>Advanced Programming in the UNIX(R) Environment</title> +<edition>1st edition</edition> +<pubdate>June 1992</pubdate> +<author><firstname>W. Richard</firstname><surname>Stevens</surname></author> +<publisher><publishername>Addison-Wesley Pub Co</publishername></publisher> +<isbn>ISBN 0201563177</isbn> +</biblioentry> + +<biblioentry> +<title>Thinking in C++, Volume 1: Introduction to Standard C++</title> +<edition>2nd Edition</edition> +<pubdate>April 15, 2000</pubdate> +<author><firstname>Bruce</firstname><surname>Eckel</surname></author> +<publisher><publishername>Prentice Hall</publishername></publisher> +<isbn>ISBN 0139798099</isbn> +</biblioentry> + +<biblioentry> +<title>Open Source Development with CVS</title> +<edition>2nd Edition</edition> +<pubdate>October 12, 2001</pubdate> +<authorgroup> +<author><firstname>Karl</firstname><surname>Fogel</surname></author> +<author><firstname>Moshe</firstname><surname>Bar</surname></author> +</authorgroup> +<publisher><publishername>The Coriolis Group</publishername></publisher> +<isbn>ISBN 158880173X</isbn> +</biblioentry> + +<biblioentry> +<title>Programming PHP</title> +<edition>1st edition</edition> +<pubdate>March 2002</pubdate> +<authorgroup> +<author><firstname>Rasmus</firstname><surname>Lerdorf</surname></author> +<author><firstname>Kevin</firstname><surname>Tatroe</surname></author> +</authorgroup> +<publisher><publishername>O'Reilly & Associates</publishername></publisher> +<isbn>ISBN 1565926102</isbn> +</biblioentry> + +<biblioentry> +<title>Programming Python</title> +<edition>2nd Edition</edition> +<pubdate>March 2001</pubdate> +<author><firstname>Mark</firstname><surname>Lutz</surname></author> +<publisher><publishername>O'Reilly & Associates</publishername></publisher> +<isbn>ISBN 0596000855</isbn> +</biblioentry> + +<biblioentry> +<title>Gui Programming With Python : Using the Qt Toolkit</title> +<edition>Bk&Cd-r edition</edition> +<pubdate>January 2002</pubdate> +<author><firstname>Boudewijn</firstname><surname>Rempt</surname></author> +<publisher><publishername>Opendocs Llc</publishername></publisher> +<isbn>ISBN 0970033044</isbn> +</biblioentry> + +<biblioentry> +<title>Programming Perl</title> +<subtitle>The Camel book</subtitle> +<edition>3rd Edition</edition> +<pubdate>July 2000</pubdate> +<authorgroup> +<author><firstname>Larry</firstname><surname>Wall</surname></author> +<author><firstname>Tom</firstname><surname>Christiansen</surname></author> +<author><firstname>Jon</firstname><surname>Orwant</surname></author> +</authorgroup> +<publisher><publishername>O'Reilly & Associates</publishername></publisher> +<isbn>ISBN 0596000278</isbn> +</biblioentry> + +<biblioentry> +<title>Learning Perl</title> +<subtitle>The Lama book</subtitle> +<edition>3rd Edition</edition> +<pubdate>July 15, 2001</pubdate> +<authorgroup> +<author><firstname>Randal L.</firstname><surname>Schwartz</surname></author> +<author><firstname>Tom</firstname><surname>Phoenix</surname></author> +</authorgroup> +<publisher><publishername>O'Reilly & Associates</publishername></publisher> +<isbn>ISBN 0596001320</isbn> +</biblioentry> + +</bibliography> + +&underFDL; + + +</appendix> + +</book> |