Flutter: FutureBuilder NoSuchMethodError isNotEmpty

Question

I've created a flutter project with FlutterBuilder with ListView.builder which get the data from JSON file (local). I successfully build the app, but just for a second the screen shown like this :

after that, my app work smoothly. Here is my code :

FutureBuilder(
                future: _isInit ? fetchDoa(context) : Future(null),
                builder: (context, _) {
                  if (doaList.isNotEmpty) {
                    return ListView.builder(
                      itemCount: doaList.length,
                      itemBuilder: (BuildContext context, int index) {
                        Doa doa = doaList[index];
                        return Card(
                            margin: EdgeInsets.all(8),
                            child: ListTile(
                                title: Text(doa.judul),
                                onTap: () {
                                  Navigator.of(context).push(MaterialPageRoute(
                                      builder: (BuildContext context) =>
                                          DoaPage(
                                            doa: doa,
                                          )));
                                },
                                trailing: IconButton(
                                  icon: Icon(
                                    doa.fav
                                        ? Icons.favorite
                                        : Icons.favorite_border,
                                    color: doa.fav ? Colors.red : null,
                                  ),
                                  onPressed: () => setState(() {
                                    doa.fav = !doa.fav;
                                  }),
                                )));
                      },
                    );
                  }
                  return CircularProgressIndicator();
                })

This is the complete preview of my app :

I need your help, Thank you very much :)

Answer 1

Make builder as

builder: (context, snapshot) {
 if(snapshot.hasData){
    if (doaList != null && doaList.isNotEmpty){
    // UI
    } else {
    // no data available
  }

 } else {
   // show loader or empty container
 }