Install event filter for QLineEdit : QLineEdit « Qt « C++

1. C++
2. Qt
3. QLineEdit

Install event filter for QLineEdit

  


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.
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 *       this list of conditions and the following disclaimer in the documentation 
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 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
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 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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 */

#include <QApplication>
#include <QLineEdit>
#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();
}

   
    
  

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