Qline edit focusIn event

[deepal_de]

hello
How can i catch a QlineEdit focusIn event from the main window..
without subclassing QlineEdit ...

[Santosh Reddy]

You can create and install an event filter, and emit a signal in there, something like this

class FocusInSignal: public QObject
{
     Q_OBJECT
     ...
signals:
     void focusIn(void);
 
protected:
     bool FocusInSignal::eventFilter(QObject *obj, QEvent *event)
     {
         if (event->type() == QEvent::FocusIn) {
             emit focusIn();
             return true;
         } else {
             // standard event processing
             return QObject::eventFilter(obj, event);
         }
     }
}
 
// in the main window
FocusInSignal* filter = new filter(this);
connect(filter, SIGNAL(focusIn()), this, SLOT(lineEditGotFucus()));
lineEdit->installFilter(filter);
 
void MainWindow::lineEditGotFucus(void)
{
    // processes
}

class FocusInSignal: public QObject
{
     Q_OBJECT
     ...
signals:
     void focusIn(void);

protected:
     bool FocusInSignal::eventFilter(QObject *obj, QEvent *event)
     {
         if (event->type() == QEvent::FocusIn) {
             emit focusIn();
             return true;
         } else {
             // standard event processing
             return QObject::eventFilter(obj, event);
         }
     }
}

// in the main window
FocusInSignal* filter = new filter(this);
connect(filter, SIGNAL(focusIn()), this, SLOT(lineEditGotFucus()));
lineEdit->installFilter(filter);

void MainWindow::lineEditGotFucus(void)
{
    // processes
}

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