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diff --git a/doc/html/tutorial1-05.html b/doc/html/tutorial1-05.html new file mode 100644 index 0000000..57e8572 --- /dev/null +++ b/doc/html/tutorial1-05.html @@ -0,0 +1,168 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> +<!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/doc/tutorial.doc:487 --> +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> +<title>Qt Tutorial - Chapter 5: Building Blocks</title> +<style type="text/css"><!-- +fn { margin-left: 1cm; text-indent: -1cm; } +a:link { color: #004faf; text-decoration: none } +a:visited { color: #672967; text-decoration: none } +body { background: #ffffff; color: black; } +--></style> +</head> +<body> + +<table border="0" cellpadding="0" cellspacing="0" width="100%"> +<tr bgcolor="#E5E5E5"> +<td valign=center> + <a href="index.html"> +<font color="#004faf">Home</font></a> + | <a href="classes.html"> +<font color="#004faf">All Classes</font></a> + | <a href="mainclasses.html"> +<font color="#004faf">Main Classes</font></a> + | <a href="annotated.html"> +<font color="#004faf">Annotated</font></a> + | <a href="groups.html"> +<font color="#004faf">Grouped Classes</font></a> + | <a href="functions.html"> +<font color="#004faf">Functions</font></a> +</td> +<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Qt Tutorial - Chapter 5: Building Blocks</h1> + + +<p> <center><img src="t5.png" alt="Screenshot of tutorial five"></center> +<p> This example shows how to create and connect together several widgets +by using signals and slots, and how to handle resize events. +<p> <pre>/**************************************************************** +** +** Qt tutorial 5 +** +****************************************************************/ + +#include <<a href="qapplication-h.html">qapplication.h</a>> +#include <<a href="qpushbutton-h.html">qpushbutton.h</a>> +#include <<a href="qslider-h.html">qslider.h</a>> +#include <<a href="qlcdnumber-h.html">qlcdnumber.h</a>> +#include <<a href="qfont-h.html">qfont.h</a>> + +#include <<a href="qvbox-h.html">qvbox.h</a>> + +class MyWidget : public <a href="qvbox.html">QVBox</a> +{ +public: + MyWidget( <a href="qwidget.html">QWidget</a> *parent=0, const char *name=0 ); +}; + + +<a name="f553"></a>MyWidget::MyWidget( <a href="qwidget.html">QWidget</a> *parent, const char *name ) + : <a href="qvbox.html">QVBox</a>( parent, name ) +{ + <a href="qpushbutton.html">QPushButton</a> *quit = new <a href="qpushbutton.html">QPushButton</a>( "Quit", this, "quit" ); + quit-><a href="qwidget.html#setFont">setFont</a>( QFont( "Times", 18, QFont::Bold ) ); + + <a href="qobject.html#connect">connect</a>( quit, SIGNAL(<a href="qbutton.html#clicked">clicked</a>()), qApp, SLOT(<a href="qapplication.html#quit">quit</a>()) ); + + <a href="qlcdnumber.html">QLCDNumber</a> *lcd = new <a href="qlcdnumber.html">QLCDNumber</a>( 2, this, "lcd" ); + + <a href="qslider.html">QSlider</a> * slider = new <a href="qslider.html">QSlider</a>( Horizontal, this, "slider" ); + slider-><a href="qrangecontrol.html#setRange">setRange</a>( 0, 99 ); + slider-><a href="qslider.html#setValue">setValue</a>( 0 ); + + <a href="qobject.html#connect">connect</a>( slider, SIGNAL(<a href="qslider.html#valueChanged">valueChanged</a>(int)), lcd, SLOT(<a href="qlcdnumber.html#display">display</a>(int)) ); +} + +int main( int argc, char **argv ) +{ + <a href="qapplication.html">QApplication</a> a( argc, argv ); + + MyWidget w; + a.<a href="qapplication.html#setMainWidget">setMainWidget</a>( &w ); + w.<a href="qwidget.html#show">show</a>(); + return a.<a href="qapplication.html#exec">exec</a>(); +} +</pre> + + + +<p> <h2> Line-by-line Walkthrough +</h2> +<a name="1"></a><p> <pre> #include <<a href="qapplication-h.html">qapplication.h</a>> + #include <<a href="qpushbutton-h.html">qpushbutton.h</a>> + #include <<a href="qslider-h.html">qslider.h</a>> + #include <<a href="qlcdnumber-h.html">qlcdnumber.h</a>> + #include <<a href="qfont-h.html">qfont.h</a>> + + #include <<a href="qvbox-h.html">qvbox.h</a>> +</pre> +<p> Three new include files are shown here. qslider.h and qlcdnumber.h are there +because we use two new widgets, <a href="qslider.html">QSlider</a> and <a href="qlcdnumber.html">QLCDNumber</a>. qvbox.h is +here because we use Qt's automatic layout support. +<p> <pre> class MyWidget : public <a href="qvbox.html">QVBox</a> + { + public: + MyWidget( <a href="qwidget.html">QWidget</a> *parent=0, const char *name=0 ); + }; +</pre> +<p> <a name="constructor"></a> +<pre> MyWidget::MyWidget( <a href="qwidget.html">QWidget</a> *parent, const char *name ) + : <a href="qvbox.html">QVBox</a>( parent, name ) + { +</pre> +<p> MyWidget is now derived from <a href="qvbox.html">QVBox</a> instead of <a href="qwidget.html">QWidget</a>. That way we use +the layout of the QVBox (which places all of its children vertically +inside itself). Resizes are now handled automatically by the QVBox and +therefore by MyWidget, too. +<p> <pre> <a href="qlcdnumber.html">QLCDNumber</a> *lcd = new <a href="qlcdnumber.html">QLCDNumber</a>( 2, this, "lcd" ); +</pre> +<p> <tt>lcd</tt> is a QLCDNumber, a widget that displays numbers in an LCD-like +fashion. This instance is set up to display two digits and to be a child of +<em>this</em>. It is named "lcd". +<p> <pre> <a href="qslider.html">QSlider</a> * slider = new <a href="qslider.html">QSlider</a>( Horizontal, this, "slider" ); + <a name="x2315"></a> slider-><a href="qrangecontrol.html#setRange">setRange</a>( 0, 99 ); + <a name="x2316"></a> slider-><a href="qslider.html#setValue">setValue</a>( 0 ); +</pre> +<p> <a href="qslider.html">QSlider</a> is a classical slider; the user can use the widget to drag +something to adjust an integer value in a range. Here we create a +horizontal one, set its range to 0-99 (inclusive, see the <a href="qrangecontrol.html#setRange">QSlider::setRange</a>() documentation) and its initial value to 0. +<p> <pre> <a name="x2317"></a><a name="x2314"></a> <a href="qobject.html#connect">connect</a>( slider, SIGNAL(<a href="qslider.html#valueChanged">valueChanged</a>(int)), lcd, SLOT(<a href="qlcdnumber.html#display">display</a>(int)) ); +</pre> +<p> Here we use the <a href="signalsandslots.html">signal/slot mechanism</a> +to connect the slider's valueChanged() signal to the LCD number's +display() slot. +<p> Whenever the slider's value changes it broadcasts the new value by +emitting the valueChanged() signal. Because that signal is connected to +the LCD number's display() slot, the slot is called when the signal is +broadcast. Neither of the objects knows about the other. This is +essential in component programming. +<p> Slots are otherwise normal C++ member functions and follow the normal +C++ access rules. +<p> <h2> Behavior +</h2> +<a name="2"></a><p> The LCD number reflects everything you do to the slider, and the +widget handles resizing well. Notice that the LCD number widget +changes in size when the window is resized (because it can), but the +others stay about the same (because otherwise they would look stupid). +<p> (See <a href="tutorial1-01.html#compiling">Compiling</a> for how to create a +makefile and build the application.) +<p> <h2> Exercises +</h2> +<a name="3"></a><p> Try changing the LCD number to add more digits or <a href="qlcdnumber.html#setMode">to change mode.</a> You can even add four push +buttons to set the number base. +<p> You can also change the slider's range. +<p> Perhaps it would have been better to use <a href="qspinbox.html">QSpinBox</a> than a slider? +<p> Try to make the application quit when the LCD number overflows. +<p> You're now ready for <a href="tutorial1-06.html">Chapter 6.</a> +<p> [<a href="tutorial1-04.html">Previous tutorial</a>] +[<a href="tutorial1-06.html">Next tutorial</a>] +[<a href="tutorial.html">Main tutorial page</a>] +<p> +<!-- eof --> +<p><address><hr><div align=center> +<table width=100% cellspacing=0 border=0><tr> +<td>Copyright © 2007 +<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a> +<td align=right><div align=right>Qt 3.3.8</div> +</table></div></address></body> +</html> |