You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
169 lines
8.1 KiB
169 lines
8.1 KiB
<!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>TQt 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>TQt 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>/****************************************************************
|
|
**
|
|
** TQt tutorial 5
|
|
**
|
|
****************************************************************/
|
|
|
|
#include <<a href="qapplication-h.html">ntqapplication.h</a>>
|
|
#include <<a href="qpushbutton-h.html">ntqpushbutton.h</a>>
|
|
#include <<a href="qslider-h.html">ntqslider.h</a>>
|
|
#include <<a href="qlcdnumber-h.html">ntqlcdnumber.h</a>>
|
|
#include <<a href="tqfont-h.html">tqfont.h</a>>
|
|
|
|
#include <<a href="qvbox-h.html">ntqvbox.h</a>>
|
|
|
|
class MyWidget : public <a href="ntqvbox.html">TQVBox</a>
|
|
{
|
|
public:
|
|
MyWidget( <a href="tqwidget.html">TQWidget</a> *parent=0, const char *name=0 );
|
|
};
|
|
|
|
|
|
<a name="f553"></a>MyWidget::MyWidget( <a href="tqwidget.html">TQWidget</a> *parent, const char *name )
|
|
: <a href="ntqvbox.html">TQVBox</a>( parent, name )
|
|
{
|
|
<a href="ntqpushbutton.html">TQPushButton</a> *quit = new <a href="ntqpushbutton.html">TQPushButton</a>( "Quit", this, "quit" );
|
|
quit-><a href="tqwidget.html#setFont">setFont</a>( TQFont( "Times", 18, TQFont::Bold ) );
|
|
|
|
<a href="tqobject.html#connect">connect</a>( quit, TQ_SIGNAL(<a href="ntqbutton.html#clicked">clicked</a>()), tqApp, TQ_SLOT(<a href="ntqapplication.html#quit">quit</a>()) );
|
|
|
|
<a href="ntqlcdnumber.html">TQLCDNumber</a> *lcd = new <a href="ntqlcdnumber.html">TQLCDNumber</a>( 2, this, "lcd" );
|
|
|
|
<a href="ntqslider.html">TQSlider</a> * slider = new <a href="ntqslider.html">TQSlider</a>( Horizontal, this, "slider" );
|
|
slider-><a href="ntqrangecontrol.html#setRange">setRange</a>( 0, 99 );
|
|
slider-><a href="ntqslider.html#setValue">setValue</a>( 0 );
|
|
|
|
<a href="tqobject.html#connect">connect</a>( slider, TQ_SIGNAL(<a href="ntqslider.html#valueChanged">valueChanged</a>(int)), lcd, TQ_SLOT(<a href="ntqlcdnumber.html#display">display</a>(int)) );
|
|
}
|
|
|
|
int main( int argc, char **argv )
|
|
{
|
|
<a href="ntqapplication.html">TQApplication</a> a( argc, argv );
|
|
|
|
MyWidget w;
|
|
a.<a href="ntqapplication.html#setMainWidget">setMainWidget</a>( &w );
|
|
w.<a href="tqwidget.html#show">show</a>();
|
|
return a.<a href="ntqapplication.html#exec">exec</a>();
|
|
}
|
|
</pre>
|
|
|
|
|
|
|
|
<p> <h2> Line-by-line Walkthrough
|
|
</h2>
|
|
<a name="1"></a><p> <pre> #include <<a href="qapplication-h.html">ntqapplication.h</a>>
|
|
#include <<a href="qpushbutton-h.html">ntqpushbutton.h</a>>
|
|
#include <<a href="qslider-h.html">ntqslider.h</a>>
|
|
#include <<a href="qlcdnumber-h.html">ntqlcdnumber.h</a>>
|
|
#include <<a href="tqfont-h.html">tqfont.h</a>>
|
|
|
|
#include <<a href="qvbox-h.html">ntqvbox.h</a>>
|
|
</pre>
|
|
<p> Three new include files are shown here. ntqslider.h and ntqlcdnumber.h are there
|
|
because we use two new widgets, <a href="ntqslider.html">TQSlider</a> and <a href="ntqlcdnumber.html">TQLCDNumber</a>. ntqvbox.h is
|
|
here because we use TQt's automatic layout support.
|
|
<p> <pre> class MyWidget : public <a href="ntqvbox.html">TQVBox</a>
|
|
{
|
|
public:
|
|
MyWidget( <a href="tqwidget.html">TQWidget</a> *parent=0, const char *name=0 );
|
|
};
|
|
</pre>
|
|
<p> <a name="constructor"></a>
|
|
<pre> MyWidget::MyWidget( <a href="tqwidget.html">TQWidget</a> *parent, const char *name )
|
|
: <a href="ntqvbox.html">TQVBox</a>( parent, name )
|
|
{
|
|
</pre>
|
|
<p> MyWidget is now derived from <a href="ntqvbox.html">TQVBox</a> instead of <a href="tqwidget.html">TQWidget</a>. That way we use
|
|
the layout of the TQVBox (which places all of its children vertically
|
|
inside itself). Resizes are now handled automatically by the TQVBox and
|
|
therefore by MyWidget, too.
|
|
<p> <pre> <a href="ntqlcdnumber.html">TQLCDNumber</a> *lcd = new <a href="ntqlcdnumber.html">TQLCDNumber</a>( 2, this, "lcd" );
|
|
</pre>
|
|
<p> <tt>lcd</tt> is a TQLCDNumber, 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="ntqslider.html">TQSlider</a> * slider = new <a href="ntqslider.html">TQSlider</a>( Horizontal, this, "slider" );
|
|
<a name="x2315"></a> slider-><a href="ntqrangecontrol.html#setRange">setRange</a>( 0, 99 );
|
|
<a name="x2316"></a> slider-><a href="ntqslider.html#setValue">setValue</a>( 0 );
|
|
</pre>
|
|
<p> <a href="ntqslider.html">TQSlider</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="ntqrangecontrol.html#setRange">TQSlider::setRange</a>() documentation) and its initial value to 0.
|
|
<p> <pre> <a name="x2317"></a><a name="x2314"></a> <a href="tqobject.html#connect">connect</a>( slider, TQ_SIGNAL(<a href="ntqslider.html#valueChanged">valueChanged</a>(int)), lcd, TQ_SLOT(<a href="ntqlcdnumber.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="ntqlcdnumber.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="ntqspinbox.html">TQSpinBox</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>TQt 3.3.8</div>
|
|
</table></div></address></body>
|
|
</html>
|