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flutterdartasynchronousio

In Flutter, is there a way in which I can draw different contents and dynamic lists from the stored file?


To solve the first problem, the method I'm currently using is to put a content variable in the body while loading the file async and when the loading is done, call setState() and set the value of content.

class _MyHomePageState extends State<MyHomePage>{
  dynamic content;
  void setContent(bool? hasRes){
    setState(() {
      if(hasRes!=null&&hasRes){
        content = const ContentWhenHasRes();
      }else{
        content = const ContentWhenNoRes();
      }
    });
  }
  @override
  Widget build(BuildContext context){
    //Load the $hasRes$ var and determine which interface to draw
    SharedPreferences.getInstance().then((pref) => {
      setContent(pref.getBool('hasRes'))
    });
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: content
    );
  }
}

But I don't know whether this works and is there a more elegant way to do this? Also, I'm finding it problematic to load a list from local storage to show in ListView. I know to use `ListView.builder' however, my problem is still with the i/o part.


Solution

  • another approach is setState() the hasRes variable:

    class _MyHomePageState extends State<MyHomePage>{
      bool _hasRes = false;
    
      @override
      void initState() {
        super.initState();
        //Do this in initState()
        SharedPreferences.getInstance().then((pref) => {
          _hasRes = pref.getBool('hasRes');
          setState((){});
        });
      }
    
      @override
      Widget build(BuildContext context){
        return Scaffold(
          appBar: AppBar(
            title: Text(widget.title),
          ),
          body: _hasRes ? ContentWhenHasRes() : ContentWhenNoRes(),
        );
      }
    }