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