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.
69 lines
3.3 KiB
69 lines
3.3 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/object.doc:572 -->
|
|
<html>
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
|
<title>Object Trees and Object Ownership</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>Object Trees and Object Ownership</h1>
|
|
|
|
|
|
|
|
<p> <a href="ntqobject.html">TQObjects</a> organize themselves in object trees.
|
|
When you create a <a href="ntqobject.html">TQObject</a> with another object as parent, it's added to
|
|
the parent's <a href="ntqobject.html#children">children()</a> list, and
|
|
is deleted when the parent is. It turns out that this approach fits
|
|
the needs of GUI objects very well. For example, a <a href="ntqaccel.html">TQAccel</a> (keyboard
|
|
accelerator) is a child of the relevant window, so when the user closes
|
|
that window, the accelerator is deleted too.
|
|
<p> The static function <a href="ntqobject.html#objectTrees">TQObject::objectTrees</a>() provides access to all
|
|
the root objects that currently exist.
|
|
<p> <a href="ntqwidget.html">TQWidget</a>, the base class of everything that appears on the screen,
|
|
extends the parent-child relationship. A child normally also becomes a
|
|
child widget, i.e. it is displayed in its parent's coordinate system
|
|
and is graphically clipped by its parent's boundaries. For example,
|
|
when the an application deletes a message box after it has been
|
|
closed, the message box's buttons and label are also deleted, just as
|
|
we'd want, because the buttons and label are children of the message
|
|
box.
|
|
<p> You can also delete child objects yourself, and they will remove
|
|
themselves from their parents. For example, when the user removes a
|
|
toolbar it may lead to the application deleting one of its <a href="ntqtoolbar.html">TQToolBar</a>
|
|
objects, in which case the tool bar's <a href="ntqmainwindow.html">TQMainWindow</a> parent would
|
|
detect the change and reconfigure its screen space accordingly.
|
|
<p> The debugging functions <a href="ntqobject.html#dumpObjectTree">TQObject::dumpObjectTree</a>() and <a href="ntqobject.html#dumpObjectInfo">TQObject::dumpObjectInfo</a>() are often useful when an application looks or
|
|
acts strangely.
|
|
<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>
|