Propagate click behind a widget

Question

I have a Stack with two widgets inside. I'm trying to detect the click on the bottom widget of the Stack, which is behind the top one.

I am using HitTestBehavior.translucent, but it only work if the GestureDetector doesn't have any child.

This is a simplified version of what i need in my app. I have a Stack which contains many tiny Cards on the screen, and there's one canvas on top of them all. Despite the canvas, I need to be able to tap on the Cards to change its content. I thought using a translucent behavior would solve my problem but it does not.

EDIT : Also, the first GestureDetector will always be in a Positioned widget.

class TestPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: SizedBox(
          height: 800,
          width: 400,
          child: Stack(
            children: [
              /// 2. ... and trigger the onTap function of this widget
              GestureDetector(
                behavior: HitTestBehavior.opaque,
                onTap: () {
                  print('TAP BOTTOM');
                },
                child: Container(
                  height: 500,
                  width: 400,
                  color: Colors.deepOrange,
                ),
              ),
              /// 1. I'm Trying to clic here...
              GestureDetector(
                behavior: HitTestBehavior.translucent,
                onTap: null,
                child: Container(
                  height: 300,
                  width: 400,
                  color: Colors.deepPurple,
                ),
              ),
            ],
          ),
        ),
        // ),
      ),
    );
  }
}

Answer 1

Wrap the widget(s) you want the click to propagate through in IgnorePointer:

IgnorePointer(
  ignoring: true,
  child: widgetThatIgnoresClicks()
)

Full sample code with which you can achieve this:

​class TestPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: SizedBox(
          height: 800,
          width: 400,
          child: Stack(
            children: [
              /// 2. ... and trigger the onTap function of this widget (WIDGET_2)
              GestureDetector(
                behavior: HitTestBehavior.opaque,
                onTap: () {
                  print('TAP BOTTOM');
                },
                child: Container(
                  height: 500,
                  width: 400,
                  color: Colors.deepOrange,
                ),
              ),
              /// Able to tap bottom
              IgnorePointer(
                ignoring: true,
                child: Container(
                  height: 300,
                  width: 400,
                  color: Colors.deepPurple,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

Also sorry for posting late here.