小编sha*_*l.k的帖子

我正在使用kotlin coroutines进行网络请求,使用扩展方法在这样的改造中调用类

public suspend fun <T : Any> Call<T>.await(): T {

  return suspendCancellableCoroutine { continuation -> 

    enqueue(object : Callback<T> {

        override fun onResponse(call: Call<T>?, response: Response<T?>) {
            if (response.isSuccessful) {
                val body = response.body()
                if (body == null) {
                    continuation.resumeWithException(
                            NullPointerException("Response body is null")
                    )
                } else {
                    continuation.resume(body)
                }
            } else {
                continuation.resumeWithException(HttpException(response))
            }
        }

        override fun onFailure(call: Call<T>, t: Throwable) {
            // Don't bother with resuming the continuation if it is already cancelled.
            if (continuation.isCancelled) return
            continuation.resumeWithException(t)
        } …

我试图在颤动中实现这样的事情

我有一个现有的android应用程序，并且在我的项目中集成了flutter，我想调用在我的主要方法中定义的flutter特定路线

class FlutterView extends StatelessWidget {
 @override
  Widget build(BuildContext context) {
  return new MaterialApp(
  title: 'Platform View',
  initialRoute: '/',
  routes: {
    '/': (context) => HomeScreen(),
    '/secound': (context) => MyCustomForm(),
    '/dashboard': (context) => DashBoardScreen(),
    '/login': (context) => LoginScreen(),
  },
  theme: new ThemeData(
    primarySwatch: Colors.red,
    textSelectionColor: Colors.red,
    textSelectionHandleColor: Colors.red,
    ),
   );
  }
}

从我的android活动中，我正在这样叫颤动

startActivity（new Intent（this，FlutterActivity.class））;

它的确打开了flutter活动，但是使用了initialRoute：'/'很好，但是有一段时间我想在打开flutter活动时针对eg（'/ dashboard'）路线打开它，我该怎么做？

我想实现下拉菜单的这种设计，但是不确定如何获得这种下拉菜单

 Container(
             padding: EdgeInsets.all(10.0),
             child: DropdownButtonHideUnderline(
               child: DropdownButton<String>(
                  items:_locations.map((String val){
                    return DropdownMenuItem<String>(
                      value: val,
                      child: Container(
                          margin: EdgeInsets.only(left: 10.0,right: 10.0),
                          child: new Text(val)
                      ),
                    );
                  }).toList(),
                  hint:Text(_SelectdType),
                  onChanged:(String val){
                    _SelectdType = val;
                    setState(() {});
                  }
           ),
             ),
           )

我正在像这样的流媒体列表进行屏幕更改，当它发出时，我更改屏幕

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

     appBloc.error.listen((data) {
     _scaffoldKey.currentState.showSnackBar(new SnackBar(content: new 
        Text(data)));
    });

     appBloc.success.listen((_) => goToDashBoardScreen(context));

}

和doToDashBoardScreen看起来像这样

Navigator.pushReplacement(context, new SlideRightRoute(widget: 
DashBoardScreen()));

但是我遇到这样的错误，但是我更改了页面。

22:05:02.446 3 info flutter.tools E/flutter (13216): NoSuchMethodError: 
The method 'ancestorStateOfType' was called on null.
22:05:02.446 4 info flutter.tools E/flutter (13216): Receiver: null
22:05:02.446 5 info flutter.tools E/flutter (13216): Tried calling: 
ancestorStateOfType(Instance of 'TypeMatcher<NavigatorState>')
22:05:02.446 6 info flutter.tools E/flutter (13216): #0      
Object.noSuchMethod (dart:core/runtime/libobject_patch.dart:48:5)
22:05:02.446 7 info flutter.tools E/flutter (13216): #1      
Navigator.of (package:flutter/src/widgets/navigator.dart:1270:19)
22:05:02.446 8 info flutter.tools E/flutter (13216): …

使用Material的芯片输入字段