How to unresister Click and Drag Event manually

Question

Hi,​I'm trying to change screen with button on a screen and hardware button.But, I don't want to add another screen because some parameter is shared,So, I use pointers for some widgets and generate/delete the widgets at runtime.However, when I press the trigger key to change screen during pressing the button on the screen and release the button after the screen has changed, the program has crashed.I think that the program try to call "Button::handleClickEvent" of the button that has already deleted but failed, it has crashed.Here's a some sample code.class sampleScreen {
~~~~~~~~~~
 virtual void setupScreen();
~~~~~~~~~~
 void buttonPressed();
 void triggerKeyPressed();
 void switchScreen();
~~~~~~~~~~
 Button* button;
~~~~~~~~~~
}
 
sampleScreen::setupScreen() {
 button = new Button();
~~~~~~~~~~
 add(*button);
 getRootContainer().invalidate();
}
 
void sampleScreen::buttonPressed() {
 switchScreen();
}
 
void sampleScreen::triggerKeyPressed() {
 switchScreen();
}
 
void sampleScreen::switchScreen() {
 remove(*button);
 delete button;
 getRootContainer().invalidate();
}​If there is a way to unresister to listen click event manually when the program switches screen.Do you know how to do this ? Or should I change plan ?

Alexandre RENOUX · Accepted Answer

Hello,I'm sorry but I still don't understand exactly what is the application about.Anyway, if you really want to remove the clickEvent from a widget (like a button), you need to implement the ClickEvent in your Screen, without calling the ClikcEvent of your ScreenBase. This way, only the ClickEvent in your screen will be executed and not the one from the widget.In the ClickEvent function implemented in your Screen, you can have a flag that authorize the click from the widget in one case but not in other cases like something as follows :void ScreenView::handleClickEvent(const ClickEvent& evt){ if(buttonExist) // execute the button clickEvent function { ScreenViewBase::handleClickEvent(evt); } // Else do nothing}In the end, I still suggest to have different screens, because constantly removing and recreating widgets at runtime on the same screen can become quite a mess and not very stable in my opinion.But if it works this way then this is what matters most ;)/Alexandre

Alexandre RENOUX · Answer

Hello,You say you don't want to add another screen because some parameters are shared but you can actually share parameters between screens.For that you need to save the parameters/variables in the Model. There's only one model in your application that is shared with all the screens.So creating another screen would be a better and easier idea./Alexandre

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