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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<title>Layout Managers</title>
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<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>
<p>
This example shows simple and intermediate use of Qt's layout
classes, <a href="qgridlayout.html">QGridLayout</a>, <a href="qboxlayout.html">QBoxLayout</a> etc.
<p> <hr>
<p> Implementation:
<p> <pre>/****************************************************************************
** $Id: qt/layout.cpp 3.3.8 edited Jan 11 14:37 $
**
** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved.
**
** This file is part of an example program for Qt. This example
** program may be used, distributed and modified without limitation.
**
*****************************************************************************/
#include <<a href="qapplication-h.html">qapplication.h</a>>
#include <<a href="qlabel-h.html">qlabel.h</a>>
#include <<a href="qcolor-h.html">qcolor.h</a>>
#include <<a href="qpushbutton-h.html">qpushbutton.h</a>>
#include <<a href="qlayout-h.html">qlayout.h</a>>
#include <<a href="qlineedit-h.html">qlineedit.h</a>>
#include <<a href="qmultilineedit-h.html">qmultilineedit.h</a>>
#include <<a href="qmenubar-h.html">qmenubar.h</a>>
#include <<a href="qpopupmenu-h.html">qpopupmenu.h</a>>
class ExampleWidget : public <a href="qwidget.html">QWidget</a>
{
public:
ExampleWidget( <a href="qwidget.html">QWidget</a> *parent = 0, const char *name = 0 );
~ExampleWidget();
};
<a name="f260"></a>ExampleWidget::ExampleWidget( <a href="qwidget.html">QWidget</a> *parent, const char *name )
: <a href="qwidget.html">QWidget</a>( parent, name )
{
// Make the top-level layout; a vertical box to contain all widgets
// and sub-layouts.
<a href="qboxlayout.html">QBoxLayout</a> *topLayout = new <a href="qvboxlayout.html">QVBoxLayout</a>( this, 5 );
// Create a menubar...
<a href="qmenubar.html">QMenuBar</a> *menubar = new <a href="qmenubar.html">QMenuBar</a>( this );
<a name="x540"></a> menubar-><a href="qmenubar.html#setSeparator">setSeparator</a>( QMenuBar::InWindowsStyle );
<a href="qpopupmenu.html">QPopupMenu</a>* popup;
popup = new <a href="qpopupmenu.html">QPopupMenu</a>( this );
popup-><a href="qmenudata.html#insertItem">insertItem</a>( "&Quit", qApp, SLOT(<a href="qapplication.html#quit">quit</a>()) );
menubar-><a href="qmenudata.html#insertItem">insertItem</a>( "&File", popup );
// ...and tell the layout about it.
<a name="x539"></a> topLayout-><a href="qlayout.html#setMenuBar">setMenuBar</a>( menubar );
// Make an hbox that will hold a row of buttons.
<a href="qboxlayout.html">QBoxLayout</a> *buttons = new <a href="qhboxlayout.html">QHBoxLayout</a>( topLayout );
int i;
for ( i = 1; i <= 4; i++ ) {
<a href="qpushbutton.html">QPushButton</a>* but = new <a href="qpushbutton.html">QPushButton</a>( this );
<a href="qstring.html">QString</a> s;
<a name="x542"></a> s.<a href="qstring.html#sprintf">sprintf</a>( "Button %d", i );
<a name="x530"></a> but-><a href="qbutton.html#setText">setText</a>( s );
// Set horizontal <a href="layout.html#stretch-factor">stretch factor</a> to 10 to let the buttons
// stretch horizontally. The buttons will not stretch
// vertically, since bigWidget below will take up vertical
// stretch.
<a name="x529"></a> buttons-><a href="qboxlayout.html#addWidget">addWidget</a>( but, 10 );
// (Actually, the result would have been the same with a
// stretch factor of 0; if no items in a layout have non-zero
// stretch, the space is divided equally between members.)
}
// Make another hbox that will hold a left-justified row of buttons.
<a href="qboxlayout.html">QBoxLayout</a> *buttons2 = new <a href="qhboxlayout.html">QHBoxLayout</a>( topLayout );
<a href="qpushbutton.html">QPushButton</a>* but = new <a href="qpushbutton.html">QPushButton</a>( "Button five", this );
buttons2-><a href="qboxlayout.html#addWidget">addWidget</a>( but );
but = new <a href="qpushbutton.html">QPushButton</a>( "Button 6", this );
buttons2-><a href="qboxlayout.html#addWidget">addWidget</a>( but );
// Fill up the rest of the hbox with stretchable space, so that
// the buttons get their minimum width and are pushed to the left.
<a name="x528"></a> buttons2-><a href="qboxlayout.html#addStretch">addStretch</a>( 10 );
// Make a big widget that will grab all space in the middle.
<a href="qmultilineedit.html">QMultiLineEdit</a> *bigWidget = new <a href="qmultilineedit.html">QMultiLineEdit</a>( this );
bigWidget-><a href="qtextedit.html#setText">setText</a>( "This widget will get all the remaining space" );
<a name="x531"></a> bigWidget-><a href="qframe.html#setFrameStyle">setFrameStyle</a>( QFrame::Panel | QFrame::Plain );
// Set vertical stretch factor to 10 to let the bigWidget stretch
// vertically. It will stretch horizontally because there are no
// widgets beside it to take up horizontal stretch.
// topLayout-><a href="qboxlayout.html#addWidget">addWidget</a>( bigWidget, 10 );
topLayout-><a href="qboxlayout.html#addWidget">addWidget</a>( bigWidget );
// Make a grid that will hold a vertical table of QLabel/QLineEdit
// pairs next to a large QMultiLineEdit.
// Don't use hard-coded row/column numbers in QGridLayout, you'll
// regret it when you have to change the layout.
const int numRows = 3;
const int labelCol = 0;
const int linedCol = 1;
const int multiCol = 2;
// Let the grid-layout have a spacing of 10 pixels between
// widgets, overriding the default from topLayout.
<a href="qgridlayout.html">QGridLayout</a> *grid = new <a href="qgridlayout.html">QGridLayout</a>( topLayout, 0, 0, 10 );
int row;
for ( row = 0; row < numRows; row++ ) {
<a href="qlineedit.html">QLineEdit</a> *ed = new <a href="qlineedit.html">QLineEdit</a>( this );
// The line edit goes in the second column
<a name="x533"></a> grid-><a href="qgridlayout.html#addWidget">addWidget</a>( ed, row, linedCol );
// Make a label that is a buddy of the line edit
<a href="qstring.html">QString</a> s;
s.<a href="qstring.html#sprintf">sprintf</a>( "Line &%d", row+1 );
<a href="qlabel.html">QLabel</a> *label = new <a href="qlabel.html">QLabel</a>( ed, s, this );
// The label goes in the first column.
grid-><a href="qgridlayout.html#addWidget">addWidget</a>( label, row, labelCol );
}
// The multiline edit will cover the entire vertical range of the
// grid (rows 0 to numRows) and stay in column 2.
<a href="qmultilineedit.html">QMultiLineEdit</a> *med = new <a href="qmultilineedit.html">QMultiLineEdit</a>( this );
<a name="x532"></a> grid-><a href="qgridlayout.html#addMultiCellWidget">addMultiCellWidget</a>( med, 0, -1, multiCol, multiCol );
// The labels will take the space they need. Let the remaining
// horizontal space be shared so that the multiline edit gets
// twice as much as the line edit.
<a name="x534"></a> grid-><a href="qgridlayout.html#setColStretch">setColStretch</a>( linedCol, 10 );
grid-><a href="qgridlayout.html#setColStretch">setColStretch</a>( multiCol, 20 );
// Add a widget at the bottom.
<a href="qlabel.html">QLabel</a>* sb = new <a href="qlabel.html">QLabel</a>( this );
sb-><a href="qlabel.html#setText">setText</a>( "Let's pretend this is a status bar" );
sb-><a href="qframe.html#setFrameStyle">setFrameStyle</a>( QFrame::Panel | QFrame::Sunken );
// This widget will use all horizontal space, and have a fixed height.
// we should have made a subclass and implemented sizePolicy there...
<a name="x545"></a><a name="x537"></a> sb-><a href="qwidget.html#setFixedHeight">setFixedHeight</a>( sb-><a href="qwidget.html#sizeHint">sizeHint</a>().height() );
<a name="x535"></a> sb-><a href="qlabel.html#setAlignment">setAlignment</a>( AlignVCenter | AlignLeft );
topLayout-><a href="qboxlayout.html#addWidget">addWidget</a>( sb );
<a name="x538"></a> topLayout-><a href="qlayout.html#activate">activate</a>();
}
ExampleWidget::~ExampleWidget()
{
// All child widgets are deleted by Qt.
// The top-level layout and all its sub-layouts are deleted by Qt.
}
int main( int argc, char **argv )
{
<a href="qapplication.html">QApplication</a> a( argc, argv );
ExampleWidget f;
a.<a href="qapplication.html#setMainWidget">setMainWidget</a>(&f);
f.<a href="qwidget.html#setCaption">setCaption</a>("Qt Example - Layouts");
f.<a href="qwidget.html#show">show</a>();
return a.<a href="qapplication.html#exec">exec</a>();
}
</pre>
<p>See also <a href="examples.html">Examples</a>.
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