在颤动中打开对话框时检测后退按钮按下

Question

我正在快速创建一个应用程序，我需要在其中显示一个警告对话框。这不是一个可忽略的对话框。但是当我按下 android 上的后退按钮时，它会被关闭。我尝试使用 WillPopScope 小部件来检测后按事件。我能够使用 WillPopScope 检测后退按钮按下，但是当对话框打开时这不起作用。任何建议和指南都会非常有帮助。谢谢

对话框创建片段：

void buildMaterialDialog(
  String dialogTitle,
  String dialogContent,
  String negativeBtnText,
  String positiveBtnText,
  String positiveTextUri) {

showDialog(
    context: context,
    barrierDismissible: false,
    builder: (BuildContext context) {
      return new AlertDialog(
        title: new Text(dialogTitle),
        content: new Text(dialogContent),
        actions: <Widget>[
          new FlatButton(
            onPressed: () {
              //Function called
              _updateDialogNegBtnClicked(isCancelable);
            },
            child: new Text(negativeBtnText),
          ),
          new FlatButton(
            onPressed: () => launch(positiveTextUri),
            child: new Text(positiveBtnText),
          ),
        ],
      );
    });}

Answer 1

后退按钮不会关闭对话框。

showDialog(
  context: context,
  barrierDismissible: false,
  builder: (BuildContext context) {
    return WillPopScope(
      onWillPop: () async => false,
      child: AlertDialog(
        title: Text('Title'),
        content: Text('This is Demo'),
        actions: <Widget>[
          FlatButton(
            onPressed: () => Navigator.pop(context),
            child: Text('Go Back'),
          ),
        ],
      ),
    );
  },
);

Answer 2

停止通过 Android 后退按钮关闭对话框的三种方法

选项一：

           onWillPop: () {
                          return Future.value(false);
                        },

选项二：

    onWillPop: () async {
                          return false;
                        },

选项三：

 onWillPop: () {}, // This will give surpress warning, try to avoid this one.

Answer 3

因为我的声誉不足以评论已接受的答案，我想为 onPressed: () {} 提供其他选择。您可以使用 onPressed: () => null。不会弹出警告。

Answer 4

要实现此行为，您可以覆盖 MaterialPageRoute 中的 hasScopedWillPopCallback getter。

class CustomMaterialPageRoute extends MaterialPageRoute {
  @protected
  bool get hasScopedWillPopCallback {
    return false;
  }
  CustomMaterialPageRoute({
    @required WidgetBuilder builder,
    RouteSettings settings,
    bool maintainState = true,
    bool fullscreenDialog = false,
  }) : super(
          builder: builder,
          settings: settings,
          maintainState: maintainState,
          fullscreenDialog: fullscreenDialog,
        );
}

然后替换路由器中 CustomMaterialPageRoute 上的 MaterialPageRoute。然后在 iOS 上滑动即可工作，WillPopScope 小部件也将工作。

Answer 5

 @override
      Widget build(BuildContext context) {
        return WillPopScope(
          onWillPop: _onBackPressed,
          child: Scaffold(
            
          ),
        );
      }
    
      Future<bool> _onBackPressed() async {
        return await showDialog(
            context: context, builder: (context) => ExitAppDialogBox());
      }

在颤动中打开对话框时检测后退按钮按下

Detect back button press while dialog is open in flutter

user-interface

android

dialog

flutter

flutter-layout