What is the equivalent code in flutter for “ mAdapter.notifyDataSetChanged();”;

问题

Befor HTTP response show loading and after https response create tab view. I successfully create tab view but my problem is after HTTP request unable to update the view in the android studio with java we use

`mAdapter.notifyDataSetChanged();
 mActivity.runOnUiThread(new Runnable() {
                                         @Override
                                         public void run() {


                                         }
                                     });`

code for doing this. what is the equivalent code in the flutter?

回答1:

If you want update any widget in flutter you should call setState((){})

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

class _MyAppState extends State<MyApp> {
  bool isLoading = false;

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

    isLoading = true;
    getData();
  }

  @override
  Widget build(BuildContext context) {
    return isLoading ? new CircularProgressIndicator() : // show list;
  }

  Future<ModelClass> getData() async {
    // get data from http
    ...
    // after processing response
    setState(() {
      isLoading = false;
    });
  }
}

回答2:

In Flutter, the UI is updated when the State is changed using setState method.

In your case, you will need some variables (E.x: isLoading, items (for your list)).

When the app loads data from backend, isLoading = true, items = [] (empty). When the request is done, isLoading = false and items = [item1, item2,...]. Here is where you have to use setState method to update your UI.

Under your build method, you have to use these 2 variables to render the corresponding UI.

来源：https://stackoverflow.com/questions/50619480/what-is-the-equivalent-code-in-flutter-for-madapter-notifydatasetchanged