使用 Navigator 时，如何解决在 null 上调用了“ancestorStateOfType”方法？

Question

我正在使用 firebase_dynamic_links: ^0.5.0 在我的颤振应用程序中实现设置密码功能。当管理员创建用户时，用户会收到一封电子邮件。在这封电子邮件中有一个动态链接。单击它时，用户将被重定向到 1.App store/play store 如果他/她没有App。 2.如果应用程序已经安装，在应用程序中打开设置密码屏幕。 firebase_dynamic_links 提供了两种方法：- 1.getInitialLink a future 以检索打开应用程序的链接。 2.onLink 一个回调来监听应用程序处于活动状态或在后台打开的链接。

当应用程序处于终止状态并按下链接时一切正常，但当应用程序处于后台时导航不起作用。

void main() => runApp(MaterialApp(
    theme: new ThemeData(
      primaryColor: Colours.appThemeColour,
    ),
    onGenerateRoute: (RouteSettings settings) {
      switch (settings.name) {
        case '/': return new MyCustomRoute(
          builder: (_) => new SplashScreen(),
          settings: settings,
        );
        case '/setpassword': return new MyCustomRoute(
          builder: (_) => new SetPassword(settings.arguments),
          settings: settings,
        );
     ...


      }
    }
)
);

class SplashScreen extends StatefulWidget {

  @override
  _SplashScreenState createState() => new _SplashScreenState();
}
class _SplashScreenState extends State<SplashScreen> {
Uri deepLink;


  _handleDeepLink(Uri deepLink) async{
    if (deepLink != null) {
      print("querParam=${deepLink.queryParameters["token"]}");
      if(deepLink.queryParameters["otp"].toString()=="1"){
        if(deepLink.queryParameters["token"]!=null){
          String _status =await _networkUtil.verifyUser(deepLink.queryParameters["token"].toString());
            Navigator.of(context).pushReplacementNamed('/setpassword',arguments: _status );


        }else{
          Navigator.of(context).pushReplacementNamed('/setpassword',arguments: "unknownError" );
        }
      }
      else{
        if(deepLink.queryParameters["token"]!=null){
          String _status =await _networkUtil.verifyUser(deepLink.queryParameters["token"].toString());
          SchedulerBinding.instance.addPostFrameCallback((_) {
            Navigator.of(context).pushReplacementNamed('/resetpassword');
          });
        }else{
          Navigator.of(context).pushReplacementNamed('/resetpassword');
        }
      }

    }
  }
}
  initDynamicLinks() async {

    final PendingDynamicLinkData data = await FirebaseDynamicLinks.instance.getInitialLink();
    final Uri deepLink = data?.link;

    if (deepLink != null) {
      _handleDeepLink(deepLink);

    }

    FirebaseDynamicLinks.instance.onLink(
        onSuccess: (PendingDynamicLinkData dynamicLink) async {
          final Uri deepLink = dynamicLink?.link;
          _handleDeepLink(deepLink);

        },
        onError: (OnLinkErrorException e) async {
          print('onLinkError');
          print(e.message);
        }
    );
  }
@override
initState(){
initDynamicLinks().then((){
...

});
}

当应用程序处于后台并单击链接时，它应该导航到设置密码屏幕，但它（通过我在下面提到的一个例外）进入当应用程序移动到后台时打开的那个屏幕。

D/ViewRootImpl@5c26021MainActivity: MSG_WINDOW_FOCUS_CHANGED 0 D/SurfaceView(25703)：Relayout 返回：oldFrame=[0,0][1440,2560] newFrame=[0,0][1440,2560] result=0x5 surface={Surface(name=null)/@0x54b5e07 isValid =假0} D/ViewRootImpl@5c26021MainActivity: mHardwareRenderer.destroy()#1 D/ViewRootImpl@5c26021MainActivity：Relayout 返回：oldFrame=[0,0][1440,2560] newFrame=[0,0][1440,2560] result=0x5 surface={isValid=false 0}surfaceGenerationChanged=true D/InputTransport(25703)：输入通道被破坏：fd=92 D/ViewRootImpl@5c26021MainActivity: mHardwareRenderer.destroy()#1 D/ViewRootImpl@5c26021MainActivity：Relayout 返回：oldFrame=[0,0][1440,2560] newFrame=[0,0][1440,2560] result=0x1 surface={isValid=false 0} surfaceGenerationChanged=false D/ViewRootImpl@5c26021MainActivity: mHardwareRenderer.destroy()#1 D/ViewRootImpl@5c26021MainActivity：Relayout 返回：oldFrame=[0,0][1440,2560] newFrame=[0,0][1440,2560] result=0x1 surface={isValid=false 0} surfaceGenerationChanged=false D/SurfaceView(25703)：Relayout 返回：oldFrame=[0,0][1440,2560] newFrame=[0,0][1440,2560] result=0x7 surface={Surface(name=null)/@0x54b5e07 isValid =真543154356736} D/mali_winsys(25703): EGLint new_window_surface(egl_winsys_display*, void*, EGLSurface, EGLConfig, egl_winsys_surface**, egl_color_buffer_format*, EGLBoolean) 返回 0x3000, [1440x2560]-format:1 I/颤振（25703）：querParam=e144efdbd666e615a47ebe18e25a556d D/ViewRootImpl@5c26021MainActivity：Relayout 返回：oldFrame=[0,0][1440,2560] newFrame=[0,0][1440,2560] result=0x7 surface={isValid=true 542519654912}surfaceGenerationChanged=true D/ViewRootImpl@5c26021MainActivity: mHardwareRenderer.initialize() mSurface={isValid=true 542519654912} hwInitialized=true D/mali_winsys(25703): EGLint new_window_surface(egl_winsys_display*, void*, EGLSurface, EGLConfig, egl_winsys_surface**, egl_color_buffer_format*, EGLBoolean) 返回 0x3000, [1440x2560]-format:1 D/ViewRootImpl@5c26021MainActivity：MSG_WINDOW_FOCUS_CHANGED 1 D/ViewRootImpl@5c26021MainActivity: mHardwareRenderer.initializeIfNeeded()#2 mSurface={isValid=true 542519654912} V/InputMethodManager(25703)：开始输入：tba=android.view.inputmethod.EditorInfo@6fb193a nm：com.root.amployee ic=null I/InputMethodManager(25703): [IMM] startInputInner - mService.startInputOrWindowGainedFocus D/InputTransport(25703)：输入通道构造：fd=93

E/flutter (25703): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] 未处理的异常: NoSuchMethodError: 方法 'ancestorStateOfType' 在 null 上被调用。 E/颤振（25703）：接收器：空 E/flutter（25703）：尝试调用：ancestStateOfType（'TypeMatcher'的实例） E/flutter (25703): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:50:5)

Answer 1

这是库本身的问题。因为您访问的context 目前无法访问。所以我建议你在MaterialApp 或CupertinoApp 中创建全局导航器状态

class MyApp extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  final _navigatorKey = GlobalKey<NavigatorState>();

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      key: _navigatorKey,
      home: Container(),
    );
  }
}