fetching data from file and to show on screen failing in flutter

July 23, 2023

I have a screen of restoring data from json file….here i want to show all data which are taken back up for restoring….

List<Note> restoreNotes=[];
  Future<void> fetchNotes() async {
    String path =
        '/storage/emulated/0/Android/data/com.example.noteapp/backup_data2.json';
    File? file = File(path);
    bool doesFileExists = await file.exists();
    if(doesFileExists==true) {
      if (await File(path).length() != 0) {
        //append data
        List<dynamic> list = jsonDecode(await file.readAsString());
        for (var i = 0; i < list.length; i++) {
          Note note = Note.fromJson(list[i] as Map<String, dynamic>);
          restoreNotes.add(note);
        }
      }
    }

  }

  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    fetchNotes();
  }

its working but i have to press refresh button for set state

later i will user ListView.builder to show this fetched data….

is it possible without using future.builder?

>Solution :

Yes, it is possible!! you can manually trigger a UI update by calling setState after the data is fetched

You need to use:

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

    WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
      fetchNotes().then((_) {
        setState(() {
            // Call setState after fetching data to trigger the UI update
         });
     });
   }

Then you need a ListView.builder to show that on Screen.

Here is an example code:

@override
  Widget build(BuildContext context) {
    // Your UI with ListView.builder using restoreNotes data
    return Scaffold(
      // Your Scaffold content here
      body: ListView.builder(
        itemCount: restoreNotes.length,
        itemBuilder: (context, index) {
          return ListTile(
            title: Text(restoreNotes[index].title),
            // Other ListTile content here
          );
        },
      ),
    );
  }