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6<title>Layout Managers</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>Layout Managers</h1>
33
34
35<p>
36This example shows simple and intermediate use of Qt's layout
37classes, <a href="qgridlayout.html">QGridLayout</a>, <a href="qboxlayout.html">QBoxLayout</a> etc.
38<p> <hr>
39<p> Implementation:
40<p> <pre>/****************************************************************************
41** $Id: layout-example.html 2051 2007-02-21 10:04:20Z chehrlic $
42**
43** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved.
44**
45** This file is part of an example program for Qt. This example
46** program may be used, distributed and modified without limitation.
47**
48*****************************************************************************/
49
50#include &lt;<a href="qapplication-h.html">qapplication.h</a>&gt;
51#include &lt;<a href="qlabel-h.html">qlabel.h</a>&gt;
52#include &lt;<a href="qcolor-h.html">qcolor.h</a>&gt;
53#include &lt;<a href="qpushbutton-h.html">qpushbutton.h</a>&gt;
54#include &lt;<a href="qlayout-h.html">qlayout.h</a>&gt;
55#include &lt;<a href="qlineedit-h.html">qlineedit.h</a>&gt;
56#include &lt;<a href="qmultilineedit-h.html">qmultilineedit.h</a>&gt;
57#include &lt;<a href="qmenubar-h.html">qmenubar.h</a>&gt;
58#include &lt;<a href="qpopupmenu-h.html">qpopupmenu.h</a>&gt;
59
60class ExampleWidget : public <a href="qwidget.html">QWidget</a>
61{
62public:
63 ExampleWidget( <a href="qwidget.html">QWidget</a> *parent = 0, const char *name = 0 );
64 ~ExampleWidget();
65};
66
67<a name="f260"></a>ExampleWidget::ExampleWidget( <a href="qwidget.html">QWidget</a> *parent, const char *name )
68 : <a href="qwidget.html">QWidget</a>( parent, name )
69{
70 // Make the top-level layout; a vertical box to contain all widgets
71 // and sub-layouts.
72 <a href="qboxlayout.html">QBoxLayout</a> *topLayout = new <a href="qvboxlayout.html">QVBoxLayout</a>( this, 5 );
73
74 // Create a menubar...
75 <a href="qmenubar.html">QMenuBar</a> *menubar = new <a href="qmenubar.html">QMenuBar</a>( this );
76<a name="x540"></a> menubar-&gt;<a href="qmenubar.html#setSeparator">setSeparator</a>( QMenuBar::InWindowsStyle );
77 <a href="qpopupmenu.html">QPopupMenu</a>* popup;
78 popup = new <a href="qpopupmenu.html">QPopupMenu</a>( this );
79 popup-&gt;<a href="qmenudata.html#insertItem">insertItem</a>( "&amp;Quit", qApp, SLOT(<a href="qapplication.html#quit">quit</a>()) );
80 menubar-&gt;<a href="qmenudata.html#insertItem">insertItem</a>( "&amp;File", popup );
81
82 // ...and tell the layout about it.
83<a name="x539"></a> topLayout-&gt;<a href="qlayout.html#setMenuBar">setMenuBar</a>( menubar );
84
85 // Make an hbox that will hold a row of buttons.
86 <a href="qboxlayout.html">QBoxLayout</a> *buttons = new <a href="qhboxlayout.html">QHBoxLayout</a>( topLayout );
87 int i;
88 for ( i = 1; i &lt;= 4; i++ ) {
89 <a href="qpushbutton.html">QPushButton</a>* but = new <a href="qpushbutton.html">QPushButton</a>( this );
90 <a href="qstring.html">QString</a> s;
91<a name="x542"></a> s.<a href="qstring.html#sprintf">sprintf</a>( "Button %d", i );
92<a name="x530"></a> but-&gt;<a href="qbutton.html#setText">setText</a>( s );
93
94 // Set horizontal <a href="layout.html#stretch-factor">stretch factor</a> to 10 to let the buttons
95 // stretch horizontally. The buttons will not stretch
96 // vertically, since bigWidget below will take up vertical
97 // stretch.
98<a name="x529"></a> buttons-&gt;<a href="qboxlayout.html#addWidget">addWidget</a>( but, 10 );
99 // (Actually, the result would have been the same with a
100 // stretch factor of 0; if no items in a layout have non-zero
101 // stretch, the space is divided equally between members.)
102 }
103
104 // Make another hbox that will hold a left-justified row of buttons.
105 <a href="qboxlayout.html">QBoxLayout</a> *buttons2 = new <a href="qhboxlayout.html">QHBoxLayout</a>( topLayout );
106
107 <a href="qpushbutton.html">QPushButton</a>* but = new <a href="qpushbutton.html">QPushButton</a>( "Button five", this );
108 buttons2-&gt;<a href="qboxlayout.html#addWidget">addWidget</a>( but );
109
110 but = new <a href="qpushbutton.html">QPushButton</a>( "Button 6", this );
111 buttons2-&gt;<a href="qboxlayout.html#addWidget">addWidget</a>( but );
112
113 // Fill up the rest of the hbox with stretchable space, so that
114 // the buttons get their minimum width and are pushed to the left.
115<a name="x528"></a> buttons2-&gt;<a href="qboxlayout.html#addStretch">addStretch</a>( 10 );
116
117 // Make a big widget that will grab all space in the middle.
118 <a href="qmultilineedit.html">QMultiLineEdit</a> *bigWidget = new <a href="qmultilineedit.html">QMultiLineEdit</a>( this );
119 bigWidget-&gt;<a href="qtextedit.html#setText">setText</a>( "This widget will get all the remaining space" );
120<a name="x531"></a> bigWidget-&gt;<a href="qframe.html#setFrameStyle">setFrameStyle</a>( QFrame::Panel | QFrame::Plain );
121
122 // Set vertical stretch factor to 10 to let the bigWidget stretch
123 // vertically. It will stretch horizontally because there are no
124 // widgets beside it to take up horizontal stretch.
125 // topLayout-&gt;<a href="qboxlayout.html#addWidget">addWidget</a>( bigWidget, 10 );
126 topLayout-&gt;<a href="qboxlayout.html#addWidget">addWidget</a>( bigWidget );
127
128 // Make a grid that will hold a vertical table of QLabel/QLineEdit
129 // pairs next to a large QMultiLineEdit.
130
131 // Don't use hard-coded row/column numbers in QGridLayout, you'll
132 // regret it when you have to change the layout.
133 const int numRows = 3;
134 const int labelCol = 0;
135 const int linedCol = 1;
136 const int multiCol = 2;
137
138 // Let the grid-layout have a spacing of 10 pixels between
139 // widgets, overriding the default from topLayout.
140 <a href="qgridlayout.html">QGridLayout</a> *grid = new <a href="qgridlayout.html">QGridLayout</a>( topLayout, 0, 0, 10 );
141 int row;
142
143 for ( row = 0; row &lt; numRows; row++ ) {
144 <a href="qlineedit.html">QLineEdit</a> *ed = new <a href="qlineedit.html">QLineEdit</a>( this );
145 // The line edit goes in the second column
146<a name="x533"></a> grid-&gt;<a href="qgridlayout.html#addWidget">addWidget</a>( ed, row, linedCol );
147
148 // Make a label that is a buddy of the line edit
149 <a href="qstring.html">QString</a> s;
150 s.<a href="qstring.html#sprintf">sprintf</a>( "Line &amp;%d", row+1 );
151 <a href="qlabel.html">QLabel</a> *label = new <a href="qlabel.html">QLabel</a>( ed, s, this );
152 // The label goes in the first column.
153 grid-&gt;<a href="qgridlayout.html#addWidget">addWidget</a>( label, row, labelCol );
154 }
155
156 // The multiline edit will cover the entire vertical range of the
157 // grid (rows 0 to numRows) and stay in column 2.
158
159 <a href="qmultilineedit.html">QMultiLineEdit</a> *med = new <a href="qmultilineedit.html">QMultiLineEdit</a>( this );
160<a name="x532"></a> grid-&gt;<a href="qgridlayout.html#addMultiCellWidget">addMultiCellWidget</a>( med, 0, -1, multiCol, multiCol );
161
162 // The labels will take the space they need. Let the remaining
163 // horizontal space be shared so that the multiline edit gets
164 // twice as much as the line edit.
165<a name="x534"></a> grid-&gt;<a href="qgridlayout.html#setColStretch">setColStretch</a>( linedCol, 10 );
166 grid-&gt;<a href="qgridlayout.html#setColStretch">setColStretch</a>( multiCol, 20 );
167
168 // Add a widget at the bottom.
169 <a href="qlabel.html">QLabel</a>* sb = new <a href="qlabel.html">QLabel</a>( this );
170 sb-&gt;<a href="qlabel.html#setText">setText</a>( "Let's pretend this is a status bar" );
171 sb-&gt;<a href="qframe.html#setFrameStyle">setFrameStyle</a>( QFrame::Panel | QFrame::Sunken );
172 // This widget will use all horizontal space, and have a fixed height.
173
174 // we should have made a subclass and implemented sizePolicy there...
175<a name="x545"></a><a name="x537"></a> sb-&gt;<a href="qwidget.html#setFixedHeight">setFixedHeight</a>( sb-&gt;<a href="qwidget.html#sizeHint">sizeHint</a>().height() );
176
177<a name="x535"></a> sb-&gt;<a href="qlabel.html#setAlignment">setAlignment</a>( AlignVCenter | AlignLeft );
178 topLayout-&gt;<a href="qboxlayout.html#addWidget">addWidget</a>( sb );
179
180<a name="x538"></a> topLayout-&gt;<a href="qlayout.html#activate">activate</a>();
181}
182
183ExampleWidget::~ExampleWidget()
184{
185 // All child widgets are deleted by Qt.
186 // The top-level layout and all its sub-layouts are deleted by Qt.
187}
188
189int main( int argc, char **argv )
190{
191 <a href="qapplication.html">QApplication</a> a( argc, argv );
192
193 ExampleWidget f;
194 a.<a href="qapplication.html#setMainWidget">setMainWidget</a>(&amp;f);
195 f.<a href="qwidget.html#setCaption">setCaption</a>("Qt Example - Layouts");
196 f.<a href="qwidget.html#show">show</a>();
197
198 return a.<a href="qapplication.html#exec">exec</a>();
199}
200</pre>
201
202<p>See also <a href="examples.html">Examples</a>.
203
204<!-- eof -->
205<p><address><hr><div align=center>
206<table width=100% cellspacing=0 border=0><tr>
207<td>Copyright &copy; 2007
208<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
209<td align=right><div align=right>Qt 3.3.8</div>
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