在Flutter上捕捉Android后退按钮事件

Question

有什么方法可以onBackPressed从Android后退按钮捕获事件吗？

我尝试了WillPopScope但是我的onWillPop功能仅在我点击材料后退箭头按钮时触发

我这样说:

class MyView extends StatelessWidget{

Widget build(BuildContext context) {

    return new WillPopScope(
      onWillPop: () async {
        debugPrint("Will pop");
        return true;
      },
      child: ScopedModel<AppModel>(
      model: new AppModel(),
      child: new Scaffold(......

我需要抓住它,因为不知何故我的屏幕在按下后退按钮时表现不正确,它弹出屏幕和它下面的屏幕,但不知何故,使用材料后退箭头按钮工作正常.

更新:

the code works, my problem was not in the pop of this screen, but on the previous screen, I use 2 MaterialApp widgets, and somehow it gave a weird behavior.

Answer 1

为了防止导航,WillPopScope是正确的方法,应该按如下方式使用:

class Page2Route extends MaterialPageRoute {
  Page2Route() : super(builder: (context) => new Page2());
}

class Page2 extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new WillPopScope(
      child: new Scaffold(
        appBar: new AppBar(
          title: new Text('Page 2'),
        ),
        body: new Center(
          child: new Text('PAGE 2'),
        ),
      ),
      onWillPop: () {
        return new Future(() => false);
      },
    );
  }
}

可以像这样调用页面:

Navigator.of(context).push(new Page2Route());

不要使用以下方法进行导航,因为它与最新的Flutter有一些问题:

Navigator.push(context, new Page2Route());

Answer 2

使用WillPopScope方法并返回false

@override
Widget build(BuildContext context) {
  return WillPopScope(
     onWillPop: () async {
        // Do something here
        print("After clicking the Android Back Button");
        return false;
     },
     child: Scaffold(
       appBar: AppBar(
          title: Text("Handling the back button"),
       ),
       body: Center(
          child: Text("Body"),
       ),
    ),
  );
}

Answer 3

这应该是有帮助的。

@override
Widget build(BuildContext context) {
  return WillPopScope(
    onWillPop: () {
      _moveToScreen2(context, );
    },
    child: Scaffold(
      key: _scaffoldKey,
      appBar: AppBar(
        leading: IconButton(
            icon: Icon(Icons.arrow_back),
            onPressed: () {
              _moveToScreen2(context);
            }),
        title: Text("Screen 1"),
      ),
    ),
  );
}

/**
* This is probably too thin to be in its own method - consider using
* `Navigator.pushReplacementNamed(context, "screen2")` directly
*/
void _moveToScreen2(BuildContext context) =>
    Navigator.pushReplacementNamed(context, "screen2");

Answer 4

您可以使用back_button_interceptor

它检测硬件后退按钮，并且在使用 persist_bottom_nav_bar 的情况下特别有用

@override
void initState() {
    super.initState();
    BackButtonInterceptor.add(myInterceptor);
  }

  @override
  void dispose() {
    BackButtonInterceptor.remove(myInterceptor);
    super.dispose();
  }

  bool myInterceptor(bool stopDefaultButtonEvent, RouteInfo info) {
    print("BACK BUTTON!"); // Do some stuff.
    return false;// return true if u want to stop back
  }

Answer 5

只是在这里添加一个重要的观点。请注意，通过使用WillPopScope，我们将失去 iOS 上的向后滑动手势。

参考： https: //github.com/flutter/flutter/issues/14203