How to disable ALT + F4

[wirasto]

If me press Escape button then dialog will close. How to prevent it ? I must installEventFilter to every widget ?

[kwisp]

you mast read abut QDialog first of all.

after that i can suggest you to reimplement void QDialog::reject() [protected]
like this

...
void reject()
{
//nothing :)
}
...

...
void reject()
{
//nothing :)
}
...

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[elizabeth.h1]

"If me press Escape button then dialog will close. How to prevent it ? I must installEventFilter to every widget ?"

You can make new class , say MyQtDialog then reimplement keyPressEvent there like
this :

class MyQtDialog:public QDialog
{
  Q_OBJECT;
.....
 
void keyPressEvent(QKeyEvent* e)
{
   if(e->key() ==  Qt::Key_Escape)
       return;
 
}
}

class MyQtDialog:public QDialog
{
  Q_OBJECT;
.....

void keyPressEvent(QKeyEvent* e)
{
   if(e->key() ==  Qt::Key_Escape)
       return;
      
}
}

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Then use this class as base class for all dialog classes.

[wirasto]

I'm not create new class for QDialog, but I reimplement keyPressEvent in protected. And works now


kwisp,
Without installEventFilter and reimplement reject(), all close function can't work anymore This is amazing

[kwisp]

wirasto,
i do not understand you

[squidge]

I think he means keyPressEvent is virtual protected, and he has overrode its function. It's a standard thing to do in Qt land.

[kwisp]

i use eventFilter and installEventFilter becouse at begining this topick had very special question -- how to disable ALT+F4(Close window by X-button in top right coner and do not close by ALT+F4) i dont know realy why author whant this... he asked - i answer.

How to disable Key_Escape in QDialog? -- It is another question. Key_Escape is special key for QDialog. It is meaning -- QDialog::reject(). And i intend that if we whant not close dialog by reject we must write subclass(class MDialog: public QDialog) and reimplement virtual slot: void reject().
But this disable button "Cancel" and X-button.

If we whant to close dialog by "Cancel"-button and X-button, and do not close by Escape(i realy do not know what for) -- It is necessary to brain scatter.

[netmat]

hi,

is this piece of code worked for any of you guys?

//

.....
case QEvent::KeyPress: {

if(((QKeyEvent*)event)->key() == Qt::Key_F4 || (((QKeyEvent*)event)->modifiers() == Qt::AltModifier)) {

...........

//



I think "||" should be "&&".
Any way thats not important, what important is is this key sequence creating the close event that can be caught?
What i feel, its not taking the control to the code put with in such condition and the widget is being closed directly?

Could any one give a clear picture of catching the event created by Alt + F4?

Edit: Its creates a closeEvent(). but can we catch the key press like above?

[squidge]

Alt+F4 is a special key sequence (like Ctrl-Alt-Del), I don't think you can trap it without writing a driver. You can however (as stated above) trap the resulting close event.

[franz]

It is a good idea in general to keep standard key combinations working in your program. It helps making your program easier to use by decreasing the learning curve.