Question

我正在使用Firestore开发一个应用程序。在我的应用主屏幕上，我正在initState()中调用Firestore监听器。当我转到下一个屏幕（屏幕B）时，则前一个屏幕（主屏幕）initState()功能在屏幕B中执行和中断侦听器。我没有在屏幕B中调用主屏幕initState（）。为什么显示？下面显示为代码。

   class MainScreen extends StatelessWidget {
    MainScreen({Key key}): super(key: key);

    //The title want to AUGR SHop
    @override
    Widget build(BuildContext context) {
        return new MaterialApp(
            title: 'My App',
            home: MyMainPage(title: 'MyApp',));
    }
    }

    class MyMainPage extends StatefulWidget {
    MyMainPage({Key key, this.title}) : super(key: key);
    final String title;


    @override
    _MyMainPageState createState() => new _MyMainPageState();
    }


    class _MyMainPageState extends State<MyMainPage> with TickerProviderStateMixin {
    _MyMainPageState();

        @override
    void initState(){
        super.initState();

        loadData();

    }

    loadData(){

        widget.authentication.getFirestore().collection("xxx").document("xxx").collection("xxx")
        .snapshots().listen((data){
                debugPrint("Entered in _loadData firebase fn in MainScreen");
        });
    }

        @override
    Widget build(BuildContext context) {
        return new  new Scaffold(
        backgroundColor: Colors.white,
            appBar: new AppBar(
            iconTheme: IconThemeData(
                color: Colors.black, //change font color here
            ),
            ),
            body:new RaisedButton(child:new Text("click),onPressed: () {redirectToScreenB();})

    }

    redirectToScreenB(
            Navigator.push(context,MaterialPageRoute(builder: (context) => ScreenB()));
            //I have used no change found
            //  Navigator.pushAndRemoveUntil(context,MaterialPageRoute(builder: (context) => ScreenB()),ModalRoute.withName('/'));

    )


    }

ScreenB的代码

    class ScreenB extends StatefulWidget {
        ScreenBage({Key key, this.title}) : super(key: key);
        final String title;
        @override
        ScreenBPageState createState() => new ScreenBPageState();
    }


    class ScreenBPageState extends State<ScreenB> with TickerProviderStateMixin {
    ScreenBPageState();

        @override
    void initState(){
        super.initState();
        debugPrint("Screen B initState");

        loadSecondData();

    }

        loadSecondData(){

            debugPrint("loadSecondData started");

            widget.authentication.getFirestore().collection("xxx").document("uid")
.collection("data").where("name", isEqualTo:"xxxx")
        .snapshots().listen((data){
                debugPrint("Entered in loadSecondData firebase fn in ScreenB");
        });
    }

进入ScreenB时输出即将出现

屏幕B initState loadSecondData已启动在MainScreen的_loadData firebase fn中输入

loadSecondData()正在停止。为什么先前的页面侦听器正在新页面中加载。我尝试了StreamBuilder，但没有尝试loadSecondData()，没有中断。

Answer 1

似乎您正在从screenA在screenB中加载相同的数据。

loadData()和loadSecondData()的代码都相同。您应该更改其中之一。

loadData（）

{
widget.authentication.getFirestore().collection("xxx").document("xxx").collection("xxx").snapshots().listen((data) {
    debugPrint("Entered in _loadData firebase fn in MainScreen");
});}

loadSecondData（）

{
debugPrint("loadSecondData started");
widget.authentication.getFirestore().collection("xxx").document("xxx").collection("xxx").snapshots().listen((data){
debugPrint("Entered in _loadData firebase fn in MainScreen");
});

Flutter Firestore监听被上一页Firestore监听打断

1 个答案: