如何在 Flutter 中显示 onclick 按钮动画布局？

Question

I want to show a transparent layout over the screen when a button is pressed.

I tried by using Stack and it works fine, but when I pressed the button inside of the function(eg. ExercisePage() ) the overlay doesn't show.

The overlay works when the value overlayShouldBeVisible==true . But changing the value of overlayShouldBeVisible from inside the ExercisePage() , button pressed event, the overlay doesn't appear.

Stack(
      fit: StackFit.passthrough,
      children: <Widget>[

        ExercisePage(),

       overlayShouldBeVisible==true?new CorrectWrongOverlay(isCorrect) : new Container() ,
      ],
    ); 

Answer 1

I don't know what you're doing inside ExercisePage() but I can give you some advice. Try to use value notifierin order to change the value of a variable https://api.flutter.dev/flutter/foundation/ValueNotifier-class.html

Based on the overlayShouldBeVisible value, you can use the if condition to show CorrectWrongOverlay or not without put another widget in the tree.