QLineEdit & keyPressEvent(QKeyEvent *)

[munna]

Hi,

I have reimplemented the keyPressEvent of QLineEdit ( Qt4). Following is the code

void LineEdit::keyPressEvent(QKeyEvent *e)
{
	if(e->key() == Qt::Key_Backtab){
              //Do something
	}
	else if(e->key() == Qt::Key_Return || e->key() == Qt::Key_Tab || e->key() == Qt::Key_Enter){
		//Do something
	}
	else{
		QLineEdit::keyPressEvent(e);
	}
}

void LineEdit::keyPressEvent(QKeyEvent *e)
{
	if(e->key() == Qt::Key_Backtab){
              //Do something
	}
	else if(e->key() == Qt::Key_Return || e->key() == Qt::Key_Tab || e->key() == Qt::Key_Enter){
		//Do something
	}
	else{
		QLineEdit::keyPressEvent(e);
	}
}

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1. When I press the tab key this part of code is not executed. Another widget which is the part of my application gets the focus (Which should have happened if I wouldn't have reimplemented the keyPressEvent). How can i override this behaviour?

2. Is Qt::KeyBacktab same as Shift+Tab?

3. Can some please show me how to use modifiers. I am trying to use it in the following way :

if(e->key() == Qt::Key_Return && e->modifiers() == Qt::ShiftModifier){
 
}

if(e->key() == Qt::Key_Return && e->modifiers() == Qt::ShiftModifier){

}

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Is it the correct way of using modifiers?

Thanks a lot.

[wysota]

AFAIR tab keys are not handled by keyPressEvents. You have to implement event() to catch them.

It's explained in the docs.

[munna]

Thanks for replying

bool LineEdit::event(QEvent *e)
{
	if(e->type() == QEvent::KeyPress){
		QKeyEvent *ke = static_cast<QKeyEvent *>(e);
		if(ke->modifiers() & Qt::ShiftModifier){
			if (ke->key() == Qt::Key_Tab) {
				editMode->focusNextWidget();
				return true;
			}
		}
		else if (ke->key() == Qt::Key_Tab) {
			editMode->focusNextWidget();
			return true;
		}
	}
	return QLineEdit::event(e);
}

bool LineEdit::event(QEvent *e)
{
	if(e->type() == QEvent::KeyPress){
		QKeyEvent *ke = static_cast<QKeyEvent *>(e);
		if(ke->modifiers() & Qt::ShiftModifier){
			if (ke->key() == Qt::Key_Tab) {
				editMode->focusNextWidget();
				return true;
			}
		}
		else if (ke->key() == Qt::Key_Tab) {
			editMode->focusNextWidget();
			return true;
		}
	}
	return QLineEdit::event(e);
}

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In the above code I am trying to achieve the same functionality for both tab and shift+tab.
Tab works perfectly whereas shift+tab is not working.

Pls help
Thanks

[zlatko]

What ke->modifiers() return ?
Maiby try use QAccel?

[munna]

When i debug the program pointer gets into the first if condition but it is not getting into the second one

if(ke->modifiers() & Qt::ShiftModifier){
     if (ke->key() == Qt::Key_Tab) {
           editMode->focusNextWidget();
           return true;
     }
}

if(ke->modifiers() & Qt::ShiftModifier){
     if (ke->key() == Qt::Key_Tab) {
           editMode->focusNextWidget();
           return true;
     }
}

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[wysota]

Shift+Tab is BackTab. Try it instead of that modifier.

BTW. Why are you reimplementing Tab to do the same it does by its own?

[zlatko]

Oh yes...it becouse first pressing its Shift. So you must catch 2 events : frist for Shift and second for Tab

[munna]

BTW. Why are you reimplementing Tab to do the same it does by its own?

I am yet to write the code for backtab. I just wanted to see how modifiers work before implementing the functionality, that is why i am calling the same function in the same place.

Thanks a lot