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6<title>Toplevel Widgets</title>
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32<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Toplevel Widgets</h1>
33
34
35
36<p>
37This example demonstrates the use of Qt's widget flags to provide
38toplevel widgets with customized window decorations.
39<p> It provides a graphical user interface for selecting different
40options for widget decoration and behavior, and passes the
41appropriate widget flags to the <a href="qwidget.html">QWidget</a> constructor.
42<a href="qwidget.html#reparent">QWidget::reparent</a>() is used to change the widget flags at runtime.
43<p> <b>Warning:</b> Note that the interpretation and functionality of the
44widget flags depends on the window manager used when running the
45application. Many window managers do not support every possible flag
46combination.
47<p> The user interface providing the different options was created using
48<a href="designer-manual.html">Qt Designer</a>. The different
49options are explained in the user interface through the use of
50tooltips and What's This help. Load the <tt>options.ui</tt> file into
51<a href="designer-manual.html">Qt Designer</a> for more details.
52<p>
53
54<pre> #include &lt;<a href="qapplication-h.html">qapplication.h</a>&gt;
55 #include "options.h"
56
57 int main( int argc, char ** argv )
58 {
59 <a href="qapplication.html">QApplication</a> a( argc, argv );
60 OptionsDialog dlg;
61 return dlg.exec();
62 }
63</pre>
64<p> The main function creates and displays the dialog for the user
65interface. Note that this dialog is modal.
66<p> The code relevant for this example is in the <tt>options.ui.h</tt>
67file.
68<p>
69
70<pre> void OptionsDialog::apply()
71 {
72 <a href="qstringlist.html">QStringList</a> flagList;
73 bool wstyle = false;
74 WFlags f = WDestructiveClose | WType_TopLevel | WStyle_Customize;
75</pre>
76<p> The <tt>apply()</tt> slot declares the <a href="qt.html#WidgetFlags">widget flag</a> variable <tt>f</tt>
77and initializes it with the values
78<ul>
79<li> <tt>WDestructiveClose</tt> - the widget will be automatically
80destroyed when it is closed,
81<li> <tt>WType_TopLevel</tt> - the widget will be top level even if it
82has a parent widget, and
83<li> <tt>WStyle_Customize</tt> - the flags override the default values
84</ul>
85Other flags are used depending on the options selected in the user
86interface.
87<p> <pre> if ( bgBorder-&gt;isChecked() ) {
88 if ( rbBorderNormal-&gt;isChecked() ) {
89 f |= WStyle_NormalBorder;
90 flagList += "WStyle_NormalBorder";
91 wstyle = true;
92 }
93 else if ( rbBorderDialog-&gt;isChecked() ) {
94 f |= WStyle_DialogBorder;
95 flagList += "WStyle_DialogBorder";
96 wstyle = true;
97 }
98</pre>The window gets a normal or dialog border depending on the selected
99option.
100<p> <pre> if ( bgTitle-&gt;isChecked() ) {
101 f |= WStyle_Title;
102 flagList += "WStyle_Title";
103 wstyle = true;
104 if ( cbTitleSystem-&gt;isChecked() ) {
105 f |= WStyle_SysMenu;
106 flagList += "WStyle_SysMenu";
107 }
108 if ( cbTitleMinimize-&gt;isChecked() ) {
109 f |= WStyle_Minimize;
110 flagList += "WStyle_Minimize";
111 }
112 if ( cbTitleMaximize-&gt;isChecked() ) {
113 f |= WStyle_Maximize;
114 flagList += "WStyle_Maximize";
115 }
116 if ( cbTitleContext-&gt;isChecked() ) {
117 f |= WStyle_ContextHelp;
118 flagList += "WStyle_ContextHelp";
119 }
120 }
121</pre>A titlebar with controls is provided if the appropriate options
122have been checked.
123<p> <pre> } else {
124 f |= WStyle_NoBorder;
125 flagList += "WStyle_NoBorder";
126 wstyle = true;
127 }
128</pre>If the window should not have a border it cannot have a titlebar.
129Widgets that provide their own (e.g. themed) window decoration
130should use this flag.
131<p> <pre> <a href="qwidget.html">QWidget</a> *parent = this;
132 if ( cbBehaviorTaskbar-&gt;isChecked() ) {
133 parent = 0;
134 f |= WGroupLeader;
135 flagList += "WGroupLeader";
136 }
137</pre>If a toplevel widget has a parent it will not have a taskbar
138entry, and on most window managers it will always stay on
139top of the parent widget. This is the standard behavior for
140dialog boxes, especially if they are modeless, and for other
141secondary toplevel widgets.
142<p> To provide a taskbar entry the widget must have no parent,
143in which case we need to use the <tt>WGroupLeader</tt> flag to
144prevent blocking through the modal main dialog. Applications
145that can have multiple toplevel windows open simultaneously
146should use this combination.
147<p> <pre> if ( cbBehaviorStays-&gt;isChecked() ) {
148 f |= WStyle_StaysOnTop /*| WX11BypassWM*/;
149 flagList += "WStyle_StaysOnTop";
150 wstyle = true;
151 }
152</pre>A toplevel widget can stay on top of the whole desktop if the
153window manager supports this functionality.
154<a href="#footnote1"><sup>(1)</sup></a><a name="footnote-call1"></a>
155<p> Widgets that display important or realtime information (i.e. IRC
156clients) might benefit from using that flag.
157<p> <pre> if ( cbBehaviorPopup-&gt;isChecked() ) {
158 f |= WType_Popup;
159 flagList += "WType_Popup";
160 }
161</pre>A popup widget is a short lived modal widget that closes
162automatically. Popup menus are a typical example for such widgets.
163<p> <pre> if ( cbBehaviorModal-&gt;isChecked() ) {
164 f |= WShowModal;
165 flagList += "WShowModal";
166 }
167</pre>A modal widget blocks input to other toplevel widgets, unless
168those are in a different modal group (see <tt>WGroupLeader</tt>).
169Dialogs are often modal, and the <a href="qdialog.html">QDialog</a> class provides an easy API
170to create and display them without the need to explicitly use this
171flag.
172<p> <pre> if ( cbBehaviorTool-&gt;isChecked() ) {
173 f |= WStyle_Tool;
174 flagList += "WStyle_Tool";
175 wstyle = true;
176 }
177
178 if (wstyle)
179 <a name="x2534"></a> flagList.<a href="qvaluelist.html#push_front">push_front</a>("WStyle_Customize");
180</pre>A tool window will never have a task bar entry (even if it
181has no parent widget), and often has a smaller window
182decoration. Tool windows are frequently used instead of
183modeless dialogs.
184<p> <pre> if ( !widget ) {
185 widget = new <a href="qvbox.html">QVBox</a>( parent, 0, f );
186 <a name="x2530"></a> widget-&gt;<a href="qframe.html#setMargin">setMargin</a>( 20 );
187 <a name="x2533"></a> <a href="qlabel.html">QLabel</a> *label = new <a href="qlabel.html">QLabel</a>(flagList.<a href="qstringlist.html#join">join</a>("&amp;nbsp;| "), widget);
188 <a name="x2532"></a> label-&gt;<a href="qlabel.html#setTextFormat">setTextFormat</a>(RichText);
189 <a name="x2531"></a> label-&gt;<a href="qlabel.html#setAlignment">setAlignment</a>(WordBreak);
190 <a href="qpushbutton.html">QPushButton</a> *okButton = new <a href="qpushbutton.html">QPushButton</a>( "Close", widget );
191 <a name="x2535"></a> connect( okButton, SIGNAL(<a href="qbutton.html#clicked">clicked</a>()), widget, SLOT(<a href="qwidget.html#close">close</a>()) );
192 <a name="x2537"></a> widget-&gt;<a href="qwidget.html#move">move</a>( pos() );
193</pre>The widget is created if it has not been created yet, or if it was
194closed (since we use the <tt>WDestructiveClose</tt> flag). Note that the
195window is not visible yet.
196<a href="#footnote2"><sup>(2)</sup></a><a name="footnote-call2"></a>
197<p> <pre> } else {
198 <a name="x2538"></a><a name="x2536"></a> widget-&gt;<a href="qwidget.html#reparent">reparent</a>( parent, f, widget-&gt;<a href="qwidget.html#geometry">geometry</a>().topLeft(), FALSE);
199 }
200</pre>If the widget has already been created the reparent() function is
201used to modify the widget's flags. The widget's geometry is not
202changed, and the window is not shown again.
203<p> <pre> <a name="x2539"></a> widget-&gt;<a href="qwidget.html#setCaption">setCaption</a>( leCaption-&gt;text() );
204 <a name="x2540"></a> widget-&gt;<a href="qwidget.html#setIcon">setIcon</a>( leIcon-&gt;text() );
205 <a name="x2541"></a> widget-&gt;<a href="qwidget.html#setWindowOpacity">setWindowOpacity</a>(double(slTransparency-&gt;maxValue() - slTransparency-&gt;value()) / 100);
206
207 <a name="x2542"></a> widget-&gt;<a href="qwidget.html#show">show</a>();
208</pre>Finally the higher level properties such as the window's caption and
209icon are set. The window transparency is set according to the slider
210value. Note that this will only have effect on systems that support
211this attribute for toplevel window.
212<p> <pre> }
213</pre>Finally the window is shown with the new attributes.
214<p> To build the example go to the toplevel directory
215(<tt>QTDIR/examples/toplevel</tt>)
216<a href="#footnote3"><sup>(3)</sup></a><a name="footnote-call3"></a>
217and run <tt>qmake</tt> to generate the makefile, then use the make tool to
218build the library.
219
220<hr>
221<ol> <li><a name="footnote1"></a>
222Unfortunately some X11 window managers also require the <tt>WX11BypassWM</tt> flag to be set in addition; but some other X11 window
223managers will have problems if this flag is set. <a href="#footnote-call1">Back...</a> <li><a name="footnote2"></a>
224The example uses <a href="qguardedptr.html">QGuardedPtr</a> to make sure that the
225pointer is reset to zero when the widget object is destroyed
226due to the <tt>WDestructiveClose</tt> flag. <a href="#footnote-call2">Back...</a> <li><a name="footnote3"></a>
227
228We use <tt>QTDIR</tt> to stand for the directory where Qt is installed.
229 <a href="#footnote-call3">Back...</a></ol>
230</hr><p>See also <a href="examples.html">Examples</a>.
231
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235<td>Copyright &copy; 2007
236<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
237<td align=right><div align=right>Qt 3.3.8</div>
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