Question 75260 in Flutter Question posted in
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WillPopScope not working on one of my screens – Flutter

I am using the flutter package back_pressed (https://pub.dev/packages/back_pressed), I also tried implementing my own code similar to theirs which uses WillPopScope.

The back_pressed plugin is working fine all over my app, except for on 1 of my screens… this screen is not listening and is doing the default behavior for when the back button is pressed on Android.

@override
  Widget build(BuildContext context) {
    SetSizes();
    return WillPopScope(
      onWillPop: () { exit(0); },
      child: Content(),
    );
  }

I have also tried this:

@override
  Widget build(BuildContext context) {
    SetSizes();
    return OnBackPressed(child: Content(), perform: LeaveScreen);
  }

void LeaveScreen() {
    print("..........................Back pressed..........................");
    var navIndex = Provider.of<AppData>(context, listen: false).navIndex;
    navIndex.jumpToTab(1);
  }

The OnBackPressed code is working everywhere else in my app, except for this screen.

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    The problem was caused because I was using a plugin for my bottom navigation, the navigation was loaded in a controller file, then the controller loaded the screens content from another file...

    Issue was I needed to implement WillPopScope on the navigation controller file.

    @override
  Widget build(BuildContext context) {
    _controller = Provider.of<AppData>(context, listen: false).navIndex;
    return WillPopScope(
      onWillPop: () async {
        if (_controller.index == 0) {
          FlutterAppMinimizer.minimize();
          return false;
        }
        return true;
      },
      child: PersistentTabView(...

  2. 0

    the problem is the exit(0). here is my WillPopScope implementation which works in my whole app:

    ...
return WillPopScope(
      onWillPop: () async => false,
      child: Scaffold(
...

    you neet to use async => false, since onWillPop which is {required Future<bool> Function()? onWillPop} expects a Future Bool not an int or something.

    Further explanation on onWillPop:

    Called to veto attempts by the user to dismiss the enclosing [ModalRoute].
    If the callback returns a Future that resolves to false, the enclosing route will not be popped.

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