C++/Qt/QLineEdit

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gui connection

<source lang="cpp"> /* 

* Copyright (c) 2006-2007, Johan Thelin
* 
* All rights reserved.
* 
* Redistribution and use in source and binary forms, with or without modification, 
* are permitted provided that the following conditions are met:
* 
*     * Redistributions of source code must retain the above copyright notice, 
*       this list of conditions and the following disclaimer.
*     * Redistributions in binary form must reproduce the above copyright notice,  
*       this list of conditions and the following disclaimer in the documentation 
*       and/or other materials provided with the distribution.
*     * Neither the name of APress nor the names of its contributors 
*       may be used to endorse or promote products derived from this software 
*       without specific prior written permission.
* 
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
  1. include "myclass.h"
  2. include <QApplication>
  3. include <QWidget>
  4. include <QVBoxLayout>
  5. include <QLabel>
  6. include <QLineEdit>

int main( int argc, char **argv ) { 

 QApplication app( argc, argv );
 QWidget widget;
 QLineEdit *lineEdit = new QLineEdit();
 QLabel *label = new QLabel();
 QVBoxLayout *layout = new QVBoxLayout();
 layout->addWidget( lineEdit );
 layout->addWidget( label );
 widget.setLayout( layout );
 MyClass *bridge = new MyClass( "", &app );
 QObject::connect(
   lineEdit, SIGNAL(textChanged(const QString&)),
   bridge, SLOT(setText(const QString&)) );
 QObject::connect(
   bridge, SIGNAL(textChanged(const QString&)),
   label, SLOT(setText(const QString&)) );
 widget.show();
 return app.exec();

}

Chapter01\gui-connection\myclass.cpp /* 

* Copyright (c) 2006-2007, Johan Thelin
* 
* All rights reserved.
* 
* Redistribution and use in source and binary forms, with or without modification, 
* are permitted provided that the following conditions are met:
* 
*     * Redistributions of source code must retain the above copyright notice, 
*       this list of conditions and the following disclaimer.
*     * Redistributions in binary form must reproduce the above copyright notice,  
*       this list of conditions and the following disclaimer in the documentation 
*       and/or other materials provided with the distribution.
*     * Neither the name of APress nor the names of its contributors 
*       may be used to endorse or promote products derived from this software 
*       without specific prior written permission.
* 
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
  1. include "myclass.h"

MyClass::MyClass( const QString &text, QObject *parent ) : QObject( parent ) { 

 m_text = text;

} const QString &MyClass::text() const { 

 return m_text;

} void MyClass::setText( const QString &text ) { 

 if( m_text == text )
   return;
 m_text = text;
 emit textChanged( m_text );

} int MyClass::getLengthOfText() const { 

 return m_text.size();

}

Chapter01\gui-connection\myclass.h /* 

* Copyright (c) 2006-2007, Johan Thelin
* 
* All rights reserved.
* 
* Redistribution and use in source and binary forms, with or without modification, 
* are permitted provided that the following conditions are met:
* 
*     * Redistributions of source code must retain the above copyright notice, 
*       this list of conditions and the following disclaimer.
*     * Redistributions in binary form must reproduce the above copyright notice,  
*       this list of conditions and the following disclaimer in the documentation 
*       and/or other materials provided with the distribution.
*     * Neither the name of APress nor the names of its contributors 
*       may be used to endorse or promote products derived from this software 
*       without specific prior written permission.
* 
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
  1. ifndef MYCLASS_H
  2. define MYCLASS_H
  3. include <QObject>
  4. include <QString>

class MyClass : public QObject { 

 Q_OBJECT

public: 

 MyClass( const QString &text, QObject *parent = 0 );
 const QString& text() const;
 int getLengthOfText() const;

public slots: 

 void setText( const QString &text );

signals: 

 void textChanged( const QString& );

private: 

 QString m_text;

};

  1. endif 


 </source>


Install event filter for QLineEdit

<source lang="cpp">

Foundations of Qt Development\Chapter06\eventfilter\main.cpp /* 

* Copyright (c) 2006-2007, Johan Thelin
* 
* All rights reserved.
* 
* Redistribution and use in source and binary forms, with or without modification, 
* are permitted provided that the following conditions are met:
* 
*     * Redistributions of source code must retain the above copyright notice, 
*       this list of conditions and the following disclaimer.
*     * Redistributions in binary form must reproduce the above copyright notice,  
*       this list of conditions and the following disclaimer in the documentation 
*       and/or other materials provided with the distribution.
*     * Neither the name of APress nor the names of its contributors 
*       may be used to endorse or promote products derived from this software 
*       without specific prior written permission.
* 
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
  1. include <QApplication>
  2. include <QLineEdit>
  3. include <QKeyEvent>

class KeyboardFilter : public QObject { public: 

 KeyboardFilter( QObject *parent = 0 ) : QObject( parent ) {}

protected: 

 bool eventFilter( QObject *dist, QEvent *event )
 {
   if( event->type() == QEvent::KeyPress )
   {
     QKeyEvent *keyEvent = static_cast<QKeyEvent*>( event );
     if( QString("1234567890").indexOf( keyEvent->text() ) != -1 )
       return true;
   }
   return false;
 }

}; int main( int argc, char **argv ) { 

 QApplication app( argc, argv );
 
 QLineEdit lineEdit;
 KeyboardFilter filter;
 
 lineEdit.installEventFilter( &filter );
 lineEdit.show();
 
 return app.exec();

} 


 </source>


Line editor

<source lang="cpp"> /****************************************************************************

    • Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
    • All rights reserved.
    • Contact: Nokia Corporation (qt-info@nokia.com)
    • This file is part of the examples of the Qt Toolkit.
    • $QT_BEGIN_LICENSE:LGPL$
    • Commercial Usage
    • Licensees holding valid Qt Commercial licenses may use this file in
    • accordance with the Qt Commercial License Agreement provided with the
    • Software or, alternatively, in accordance with the terms contained in
    • a written agreement between you and Nokia.
    • GNU Lesser General Public License Usage
    • Alternatively, this file may be used under the terms of the GNU Lesser
    • General Public License version 2.1 as published by the Free Software
    • Foundation and appearing in the file LICENSE.LGPL included in the
    • packaging of this file. Please review the following information to
    • ensure the GNU Lesser General Public License version 2.1 requirements
    • will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
    • In addition, as a special exception, Nokia gives you certain additional
    • rights. These rights are described in the Nokia Qt LGPL Exception
    • version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
    • GNU General Public License Usage
    • Alternatively, this file may be used under the terms of the GNU
    • General Public License version 3.0 as published by the Free Software
    • Foundation and appearing in the file LICENSE.GPL included in the
    • packaging of this file. Please review the following information to
    • ensure the GNU General Public License version 3.0 requirements will be
    • met: http://www.gnu.org/copyleft/gpl.html.
    • If you have questions regarding the use of this file, please contact
    • Nokia at qt-info@nokia.com.
    • $QT_END_LICENSE$
                                                                                                                                                        • /
  1. ifndef WINDOW_H
  2. define WINDOW_H
  3. include <QWidget>

QT_BEGIN_NAMESPACE class QComboBox; class QLineEdit; QT_END_NAMESPACE

class Window : public QWidget { 

   Q_OBJECT

public: 

   Window();

public slots: 

   void echoChanged(int);
   void validatorChanged(int);
   void alignmentChanged(int);
   void inputMaskChanged(int);
   void accessChanged(int);

private: 

   QLineEdit *echoLineEdit;
   QLineEdit *validatorLineEdit;
   QLineEdit *alignmentLineEdit;
   QLineEdit *inputMaskLineEdit;
   QLineEdit *accessLineEdit;

};

  1. endif


  1. include <QtGui>
  2. include "window.h"

Window::Window() { 

   QGroupBox *echoGroup = new QGroupBox(tr("Echo"));
   QLabel *echoLabel = new QLabel(tr("Mode:"));
   QComboBox *echoComboBox = new QComboBox;
   echoComboBox->addItem(tr("Normal"));
   echoComboBox->addItem(tr("Password"));
   echoComboBox->addItem(tr("PasswordEchoOnEdit"));
   echoComboBox->addItem(tr("No Echo"));
   echoLineEdit = new QLineEdit;
   echoLineEdit->setFocus();

   QGroupBox *validatorGroup = new QGroupBox(tr("Validator"));
   QLabel *validatorLabel = new QLabel(tr("Type:"));
   QComboBox *validatorComboBox = new QComboBox;
   validatorComboBox->addItem(tr("No validator"));
   validatorComboBox->addItem(tr("Integer validator"));
   validatorComboBox->addItem(tr("Double validator"));
   validatorLineEdit = new QLineEdit;

   QGroupBox *alignmentGroup = new QGroupBox(tr("Alignment"));
   QLabel *alignmentLabel = new QLabel(tr("Type:"));
   QComboBox *alignmentComboBox = new QComboBox;
   alignmentComboBox->addItem(tr("Left"));
   alignmentComboBox->addItem(tr("Centered"));
   alignmentComboBox->addItem(tr("Right"));
   alignmentLineEdit = new QLineEdit;

   QGroupBox *inputMaskGroup = new QGroupBox(tr("Input mask"));
   QLabel *inputMaskLabel = new QLabel(tr("Type:"));
   QComboBox *inputMaskComboBox = new QComboBox;
   inputMaskComboBox->addItem(tr("No mask"));
   inputMaskComboBox->addItem(tr("Phone number"));
   inputMaskComboBox->addItem(tr("ISO date"));
   inputMaskComboBox->addItem(tr("License key"));
   inputMaskLineEdit = new QLineEdit;

   QGroupBox *accessGroup = new QGroupBox(tr("Access"));
   QLabel *accessLabel = new QLabel(tr("Read-only:"));
   QComboBox *accessComboBox = new QComboBox;
   accessComboBox->addItem(tr("False"));
   accessComboBox->addItem(tr("True"));
   accessLineEdit = new QLineEdit;

   connect(echoComboBox, SIGNAL(activated(int)),
           this, SLOT(echoChanged(int)));
   connect(validatorComboBox, SIGNAL(activated(int)),
           this, SLOT(validatorChanged(int)));
   connect(alignmentComboBox, SIGNAL(activated(int)),
           this, SLOT(alignmentChanged(int)));
   connect(inputMaskComboBox, SIGNAL(activated(int)),
           this, SLOT(inputMaskChanged(int)));
   connect(accessComboBox, SIGNAL(activated(int)),
           this, SLOT(accessChanged(int)));

   QGridLayout *echoLayout = new QGridLayout;
   echoLayout->addWidget(echoLabel, 0, 0);
   echoLayout->addWidget(echoComboBox, 0, 1);
   echoLayout->addWidget(echoLineEdit, 1, 0, 1, 2);
   echoGroup->setLayout(echoLayout);

   QGridLayout *validatorLayout = new QGridLayout;
   validatorLayout->addWidget(validatorLabel, 0, 0);
   validatorLayout->addWidget(validatorComboBox, 0, 1);
   validatorLayout->addWidget(validatorLineEdit, 1, 0, 1, 2);
   validatorGroup->setLayout(validatorLayout);
   QGridLayout *alignmentLayout = new QGridLayout;
   alignmentLayout->addWidget(alignmentLabel, 0, 0);
   alignmentLayout->addWidget(alignmentComboBox, 0, 1);
   alignmentLayout->addWidget(alignmentLineEdit, 1, 0, 1, 2);
   alignmentGroup-> setLayout(alignmentLayout);
   QGridLayout *inputMaskLayout = new QGridLayout;
   inputMaskLayout->addWidget(inputMaskLabel, 0, 0);
   inputMaskLayout->addWidget(inputMaskComboBox, 0, 1);
   inputMaskLayout->addWidget(inputMaskLineEdit, 1, 0, 1, 2);
   inputMaskGroup->setLayout(inputMaskLayout);
   QGridLayout *accessLayout = new QGridLayout;
   accessLayout->addWidget(accessLabel, 0, 0);
   accessLayout->addWidget(accessComboBox, 0, 1);
   accessLayout->addWidget(accessLineEdit, 1, 0, 1, 2);
   accessGroup->setLayout(accessLayout);

   QGridLayout *layout = new QGridLayout;
   layout->addWidget(echoGroup, 0, 0);
   layout->addWidget(validatorGroup, 1, 0);
   layout->addWidget(alignmentGroup, 2, 0);
   layout->addWidget(inputMaskGroup, 0, 1);
   layout->addWidget(accessGroup, 1, 1);
   setLayout(layout);
   setWindowTitle(tr("Line Edits"));

}

void Window::echoChanged(int index) { 

   switch (index) {
   case 0:
       echoLineEdit->setEchoMode(QLineEdit::Normal);
       break;
   case 1:
       echoLineEdit->setEchoMode(QLineEdit::Password);
       break;
   case 2:
     echoLineEdit->setEchoMode(QLineEdit::PasswordEchoOnEdit);
       break;
   case 3:
       echoLineEdit->setEchoMode(QLineEdit::NoEcho);
   }

}

void Window::validatorChanged(int index) { 

   switch (index) {
   case 0:
       validatorLineEdit->setValidator(0);
       break;
   case 1:
       validatorLineEdit->setValidator(new QIntValidator(
           validatorLineEdit));
       break;
   case 2:
       validatorLineEdit->setValidator(new QDoubleValidator(-999.0,
           999.0, 2, validatorLineEdit));
   }
   validatorLineEdit->clear();

}

void Window::alignmentChanged(int index) { 

   switch (index) {
   case 0:
       alignmentLineEdit->setAlignment(Qt::AlignLeft);
       break;
   case 1:
       alignmentLineEdit->setAlignment(Qt::AlignCenter);
       break;
   case 2:
     alignmentLineEdit->setAlignment(Qt::AlignRight);
   }

}

void Window::inputMaskChanged(int index) { 

   switch (index) {
   case 0:
       inputMaskLineEdit->setInputMask("");
       break;
   case 1:
       inputMaskLineEdit->setInputMask("+99 99 99 99 99;_");
       break;
   case 2:
       inputMaskLineEdit->setInputMask("0000-00-00");
       inputMaskLineEdit->setText("00000000");
       inputMaskLineEdit->setCursorPosition(0);
       break;
   case 3:
       inputMaskLineEdit->setInputMask(">AAAAA-AAAAA-AAAAA-AAAAA-AAAAA;#");
   }

}

void Window::accessChanged(int index) { 

   switch (index) {
   case 0:
       accessLineEdit->setReadOnly(false);
       break;
   case 1:
       accessLineEdit->setReadOnly(true);
   }

}


  1. include <QApplication>
  2. include "window.h"

int main(int argc, char *argv[]) { 

   QApplication app(argc, argv);
   Window window;
   window.show();
   return app.exec();

} 


 </source>


Link QLabel and QLineEdit

<source lang="cpp"> /****************************************************************************

    • Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
    • All rights reserved.
    • Contact: Nokia Corporation (qt-info@nokia.com)
    • This file is part of the documentation of the Qt Toolkit.
    • $QT_BEGIN_LICENSE:LGPL$
    • Commercial Usage
    • Licensees holding valid Qt Commercial licenses may use this file in
    • accordance with the Qt Commercial License Agreement provided with the
    • Software or, alternatively, in accordance with the terms contained in
    • a written agreement between you and Nokia.
    • GNU Lesser General Public License Usage
    • Alternatively, this file may be used under the terms of the GNU Lesser
    • General Public License version 2.1 as published by the Free Software
    • Foundation and appearing in the file LICENSE.LGPL included in the
    • packaging of this file. Please review the following information to
    • ensure the GNU Lesser General Public License version 2.1 requirements
    • will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
    • In addition, as a special exception, Nokia gives you certain additional
    • rights. These rights are described in the Nokia Qt LGPL Exception
    • version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
    • GNU General Public License Usage
    • Alternatively, this file may be used under the terms of the GNU
    • General Public License version 3.0 as published by the Free Software
    • Foundation and appearing in the file LICENSE.GPL included in the
    • packaging of this file. Please review the following information to
    • ensure the GNU General Public License version 3.0 requirements will be
    • met: http://www.gnu.org/copyleft/gpl.html.
    • If you have questions regarding the use of this file, please contact
    • Nokia at qt-info@nokia.com.
    • $QT_END_LICENSE$
                                                                                                                                                        • /
  1. include <QtGui>

class Updater : public QObject { 

   Q_OBJECT

public: 

   Updater(QWidget *widget);

public slots: 

   void adjustSize();

private: 

   QWidget *widget;

}; Updater::Updater(QWidget *widget) 

   : widget(widget)

{ } void Updater::adjustSize() { 

   widget->adjustSize();

} int main(int argc, char *argv[]) { 

   QApplication app(argc, argv);
   QLabel *label = new QLabel("My label");
   QLineEdit *editor = new QLineEdit("New text");
   QWidget window;
   //Updater updater(&label);
   QObject::connect(editor, SIGNAL(textChanged(const QString &)),
                    label, SLOT(setText(const QString &)));
   //QObject::connect(editor, SIGNAL(textChanged(const QString &)),
   //                 &updater, SLOT(adjustSize()));
   //editor.show();
   //label.show();
   QVBoxLayout *layout = new QVBoxLayout;
   layout->addWidget(label);
   layout->addWidget(editor);
   window.setLayout(layout);
   window.show();
   return app.exec();

}

  1. include "main.moc"


 </source>


Using QLineEdit

<source lang="cpp"> /* 

* Copyright (c) 2006-2007, Johan Thelin
* 
* All rights reserved.
* 
* Redistribution and use in source and binary forms, with or without modification, 
* are permitted provided that the following conditions are met:
* 
*     * Redistributions of source code must retain the above copyright notice, 
*       this list of conditions and the following disclaimer.
*     * Redistributions in binary form must reproduce the above copyright notice,  
*       this list of conditions and the following disclaimer in the documentation 
*       and/or other materials provided with the distribution.
*     * Neither the name of APress nor the names of its contributors 
*       may be used to endorse or promote products derived from this software 
*       without specific prior written permission.
* 
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
  1. include <QApplication>
  2. include <QDialog>
  3. include <QLineEdit>
  4. include <QLabel>
  5. include <QGridLayout>

int main( int argc, char **argv ) { 

 QApplication app( argc, argv );
 
 QDialog dlg;
 
 QLabel *fooLabel = new QLabel( "&Foo:" );
 QLabel *barLabel = new QLabel( "&Bar:" );
 QLineEdit *fooEdit = new QLineEdit();
 QLineEdit *barEdit = new QLineEdit();
 
 fooLabel->setBuddy( fooEdit );
 barLabel->setBuddy( barEdit );
 
 QGridLayout *layout = new QGridLayout( &dlg );
 layout->addWidget( fooLabel, 0, 0 );
 layout->addWidget( fooEdit, 0, 1 );
 layout->addWidget( barLabel, 1, 0 );
 layout->addWidget( barEdit, 1, 1 );
 dlg.show();
 
 return app.exec();

} 


 </source>
Источник — «http://cppe.ru/index.php?title=C%2B%2B/Qt/QLineEdit&oldid=1149»