The argument type 'Future<>' can't be assigned to the parameter type '' - flutter

Question

I am trying to build a GridView list. This all works when I create a simple list of 'players', but now I am trying to persist data using sqflite and I am getting an error:
Error: The argument type 'Future' can't be assigned to the parameter type 'int'
This is my list builder widget:
class PlayerList extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Consumer<PlayerData>(
builder: (context, playerData, child) {
return GridView.builder(
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: 2,
mainAxisSpacing: 20,
crossAxisSpacing: 20,
),
itemCount: playerData.playerCount,
itemBuilder: (BuildContext context, int index) {
final player = playerData.players[index];
return RawMaterialButton(
fillColor: Color(0x991c5597),
elevation: 20,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10),
),
child: Padding(
padding: const EdgeInsets.all(10.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
CircleAvatar(
backgroundColor: Colors.tealAccent,
radius: 30,
child: Icon(
Icons.star,
color: Color(0xFF16377a),
size: 30,
),
),
Text(player.name, style: smallTitleText),
],
),
),
onPressed: () {
playerData.makeActive(player.name);
playerData.printList();
Navigator.pushNamed(context, PlayScreen.id);
});
});
},
);
}
}
This is how I get the list count:
Future<int> get playerCount async {
final Database db = await getDBConnector();
final List<Map<String, dynamic>> maps = await db.query('players');
if (maps.length != null) {
return maps.length;
} else { return 0;}
}

Answer 1

Wrap your GridView with FutureBuilder
Something like this
return FutureBuilder(
future: playerData.playerCount,
builder : (context,snapshot){
if(!(snapshot.hasData)){
return Container();
}
else{
return GridView.builder(
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: 2,
mainAxisSpacing: 20,
crossAxisSpacing: 20,
),
itemCount: snapshot.data,
itemBuilder: (BuildContext context, int index) {
final player = playerData.players[index];
return RawMaterialButton(
fillColor: Color(0x991c5597),
elevation: 20,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10),
),
child: Padding(
padding: const EdgeInsets.all(10.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
CircleAvatar(
backgroundColor: Colors.tealAccent,
radius: 30,
child: Icon(
Icons.star,
color: Color(0xFF16377a),
size: 30,
),
),
Text(player.name, style: smallTitleText),
],
),
),
onPressed: () {
playerData.makeActive(player.name);
playerData.printList();
Navigator.pushNamed(context, PlayScreen.id);
});
});
},
);
}
}
);

Answer 2

The error is appearing because playerCount isn't returning int its returning a Future. First, you have to change your class to a stateful widget and load your data as shown below
class PlayerList extends StatefulWidget {
#override
_PlayerListState createState() => _PlayerListState();
}
class _PlayerListState extends State<PlayerList> {
int count;
#override
void initState() {
super.initState();
loadPlayerCount();
}
#override
Widget build(BuildContext context) {
return Consumer<PlayerData>(
builder: (context, playerData, child) {
return GridView.builder(
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: 2,
mainAxisSpacing: 20,
crossAxisSpacing: 20,
),
itemCount: count??0,
itemBuilder: (BuildContext context, int index) {
final player = playerData.players[index];
return RawMaterialButton(
fillColor: Color(0x991c5597),
elevation: 20,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10),
),
child: Padding(
padding: const EdgeInsets.all(10.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
CircleAvatar(
backgroundColor: Colors.tealAccent,
radius: 30,
child: Icon(
Icons.star,
color: Color(0xFF16377a),
size: 30,
),
),
Text(player.name, style: smallTitleText),
],
),
),
onPressed: () {
playerData.makeActive(player.name);
playerData.printList();
Navigator.pushNamed(context, PlayScreen.id);
});
});
},
);
}
void loadPlayerCount() async{
final Database db = await getDBConnector();
final List<Map<String, dynamic>> maps = await db.query('players');
if (maps.length != null) {
setState(() {
this.count = maps.length;
});
} else {
setState(() {
this.count = 0;
});
}
}
}