Question 76042 in Flutter Question posted in
The official Flutter documentation can be found here.

Use getApplicationDocumentsDirectory() to get path before using it in FutureBuilder – Flutter

In this Flutter app, I want to build a list of items with thumbnails that are stored as file names in the database. The files are stored inside the application’s directory and only the name is saved in the database.

When I build the list, I want to get the application’s directory then join it with the file name. But I don’t know how to do it because getApplicationDocumentsDirectory() is asynchronous and it doesn’t return the value when I need it (before using ListView.builder)

My code, to make it clearer

class _ItemsWidgetState extends State<ItemsWidget> {
  String? appDir;

  @override
  void initState() {
    // this seems like the only place where I can get it
    getApplicationDocumentsDirectory().then((value) => appDir = value.path);
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
        future: widget.items,
        initialData: const [],
        builder: (context, snapshot) {
          return snapshot.hasData && snapshot.data!.isNotEmpty
              ? ListView.builder(
                  itemCount: snapshot.data?.length,
                  itemBuilder: (_, int index) {
                    final Item item = snapshot.data![index];
                    // $aappDir is NULL here
                    return ListTile(
                      leading: Image.file(File('$appDir/${item.thumbnailName}')),
                      title: Text(item.name,),
                    );
                  })
              : Center(child: Text('No items added'),),
          );
        });
  }
}

As you can see, appDir is null and initState() does not change that, even though it does get the directory. I need to understand better how this works and how can I make this work

Tags:

2

Answers


  1. 0

    Try as follows:

    void main() async {
  WidgetsFlutterBinding.ensureInitialized(); // <-- This can save your life
  final Directory documentDirectory = await getApplicationDocumentsDirectory();
  print (documentDirectory);

  runApp(_App());
}
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  2. 0

    getApplicationDocumentsDirectory().then((value) => setState(() => appDir = value.path));

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