_FutureBuilderState<dynamic>The getter 'length' was called on null. Receiver: null Tried calling: length - flutter

Question

My method getting the data from db and displaying on the console. I tried several hints given in the other posts as well with no luck.
_getUsers() async {
print("getting");
var data = await http.post("http://10.0.2.2/Flutter/getdata.php", body: {
"date": formattedDate,
});
var jsonData = json.decode(data.body);
print(jsonData);
}
However the future builder not able to display:
new FutureBuilder(
future: _getUsers(),
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.connectionState == ConnectionState.waiting) {
return Center(
child: CircularProgressIndicator(),
);
}
if (snapshot.hasError) {
return Center(
child: new Text('Error ${snapshot.error}'),
);
} else {
return Center(
child: Padding(
padding: const EdgeInsets.fromLTRB(56.0, 8.0, 56.0, 8.0),
//Here I guarded against the null as well:
child: ListView.builder(
itemCount: snapshot.data.length == null // showing error here
? 0
: snapshot.data.length,
itemBuilder: (BuildContext context, int index) {
return ListTile(
leading: new Text(
'${snapshot.data[index]["branch"]}',
style: TextStyle(
color: Colors.white,
fontSize: 25.0,
),
),
trailing: new Text(
'${snapshot.data[index]["count(`branch`)".toString()]}',
style: TextStyle(
color: Colors.white,
fontSize: 25.0,
),
),
);
}),
),
);
}
}),
How can I solve the issue?

Answer 1

you should return jsonData in _getUser().
getUsers() async {
print("getting");
var data = await http.post("http://10.0.2.2/Flutter/getdata.php", body: {
"date": formattedDate,
});
var jsonData = json.decode(data.body);
return jsonData;
}
, and change this
itemCount: snapshot.data.length == null // showing error here
? 0
: snapshot.data.length,
to this
itemCount: snapshot.data?.length ?? 0,
snapshot.data? checks whether the data is null or not. ?? executes its successor when the predecessor is null.

Answer 2

Your function doesn't return any Future, therefore the FutureBuilder is unable to get a Future to run on.
_getUsers() {
print("getting");
return http.post("http://10.0.2.2/Flutter/getdata.php", body: {
"date": formattedDate,
});
}
It needs to return a Future, you shouldn't be using await because the FutureBuilder depends on an actual Future, not data. You obtain the data inside the builder and then decode it.
new FutureBuilder(
future: _getUsers(),
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.connectionState == ConnectionState.waiting) {
return Center(
child: CircularProgressIndicator(),
);
}
if (snapshot.hasError) {
return Center(
child: new Text('Error ${snapshot.error}'),
);
} else if (snapshot.hasData) { // checking for data
return Center(
child: Padding(
padding: const EdgeInsets.symmetric(horizontal: 56, vertical: 8),
child: ListView.builder(
itemCount: snapshot.data.length,
itemBuilder: (BuildContext context, int index) {
return ListTile(
leading: new Text(
'${snapshot.data[index]["branch"]}',
style: TextStyle(
color: Colors.white,
fontSize: 25.0,
),
),
trailing: new Text(
'${snapshot.data[index]["count(`branch`)".toString()]}',
style: TextStyle(
color: Colors.white,
fontSize: 25.0,
),
),
);
}),
),
);
}
}),