diff options
Diffstat (limited to 'doc/html/tutorial1-02.html')
| -rw-r--r-- | doc/html/tutorial1-02.html | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/doc/html/tutorial1-02.html b/doc/html/tutorial1-02.html new file mode 100644 index 000000000..125537d4c --- /dev/null +++ b/doc/html/tutorial1-02.html @@ -0,0 +1,128 @@ +<!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:216 --> +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> +<title>TQt Tutorial - Chapter 2: Calling it Quits</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 2: Calling it Quits</h1> + + +<p> <center><img src="t2.png" alt="Screenshot of tutorial two"></center> +<p> Having created a window in <a href="tutorial1-01.html">Chapter 1,</a> we will +now go on to make the application tquit properly when the user tells it to. +<p> We will also use a font that is more exciting than the default one. +<p> <pre>/**************************************************************** +** +** TQt tutorial 2 +** +****************************************************************/ + +#include <<a href="qapplication-h.html">qapplication.h</a>> +#include <<a href="qpushbutton-h.html">qpushbutton.h</a>> +#include <<a href="qfont-h.html">qfont.h</a>> + + +int main( int argc, char **argv ) +{ + <a href="qapplication.html">TQApplication</a> a( argc, argv ); + + <a href="qpushbutton.html">TQPushButton</a> tquit( "Quit", 0 ); + tquit.<a href="qwidget.html#resize">resize</a>( 75, 30 ); + tquit.<a href="qwidget.html#setFont">setFont</a>( TQFont( "Times", 18, TQFont::Bold ) ); + + TQObject::<a href="qobject.html#connect">connect</a>( &tquit, SIGNAL(<a href="qbutton.html#clicked">clicked</a>()), &a, SLOT(<a href="qapplication.html#tquit">tquit</a>()) ); + + a.<a href="qapplication.html#setMainWidget">setMainWidget</a>( &tquit ); + tquit.<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="qfont-h.html">qfont.h</a>> +</pre> +<p> Since this program uses <a href="qfont.html">TQFont</a>, it needs to include qfont.h. TQt's font +abstraction is rather different from the horror provided by X, and +loading and using fonts has been highly optimized. +<p> <pre> <a href="qpushbutton.html">TQPushButton</a> tquit( "Quit", 0 ); +</pre> +<p> This time, the button says "Quit" and that's exactly what the program +will do when the user clicks the button. This is not a coincidence. +We still pass 0 as the parent, since the button is a top-level window. +<p> <pre> <a name="x2292"></a> tquit.<a href="qwidget.html#resize">resize</a>( 75, 30 ); +</pre> +<p> We've chosen another size for the button since the text is a bit +shorter than "Hello world!". We could also have used <a href="qfontmetrics.html">TQFontMetrics</a> +to set right size. +<p> <pre> <a name="x2293"></a> tquit.<a href="qwidget.html#setFont">setFont</a>( TQFont( "Times", 18, TQFont::Bold ) ); +</pre> +<p> Here we choose a new font for the button, an 18-point bold font from +the Times family. Note that we create the font on the spot. +<p> It is also possible to change the default font (using <a href="qapplication.html#setFont">TQApplication::setFont</a>()) for the whole application. +<p> <pre> <a name="x2291"></a><a name="x2290"></a><a name="x2288"></a> TQObject::<a href="qobject.html#connect">connect</a>( &tquit, SIGNAL(<a href="qbutton.html#clicked">clicked</a>()), &a, SLOT(<a href="qapplication.html#tquit">tquit</a>()) ); +</pre> +<p> connect() is perhaps <em>the</em> most central feature of TQt. +Note that connect() is a static function in <a href="qobject.html">TQObject</a>. Do not confuse it +with the connect() function in the socket library. +<p> This line establishes a one-way connection between two TQt objects (objects +that inherit TQObject, directly or indirectly). Every TQt object can have +both <tt>signals</tt> (to send messages) and <tt>slots</tt> (to receive messages). All +widgets are TQt objects. They inherit <a href="qwidget.html">TQWidget</a> which in turn inherits +TQObject. +<p> Here, the <em>clicked()</em> signal of <em>tquit</em> is connected to the <em>tquit()</em> slot of <em>a</em>, so that when the button is clicked, the +application tquits. +<p> The <a href="signalsandslots.html">Signals and Slots</a> documentation +describes this topic in detail. +<p> <h2> Behavior +</h2> +<a name="2"></a><p> When you run this program, you will see an even smaller window than in +Chapter 1, filled with an even smaller button. +<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 to resize the window. Press the button. Oops! That connect() +would seem to make some difference. +<p> Are there any other signals in <a href="qpushbutton.html">TQPushButton</a> you can connect to tquit? +Hint: The TQPushButton inherits most of its behavior from <a href="qbutton.html">TQButton</a>. +<p> You're now ready for <a href="tutorial1-03.html">Chapter 3.</a> +<p> [<a href="tutorial1-01.html">Previous tutorial</a>] +[<a href="tutorial1-03.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> |