FutureBuilder return passed to var Flutter - flutter

Question

I need to store some data inside a ".txt" file into a variable.
To do this I'm using a FutureBuilder.
The idea is to handle the reading action (async) with FutureBuilder and pass the FutureBuilder return to my global variable that will be updated when needed.
Future<String> _read() async {
try {
final file = await _localBio;
String body = await file.readAsString();
// Read the file.
return body;
} catch (e) {
// If encountering an error, return 0.
return "Can't read";
}
}
var bio ="";
String _ReadBio(){
FutureBuilder<String>(
future: _read(),
builder: (context, snapshot){
if (snapshot.hasData) {
bio=snapshot.data.toString(); //this isn't done
return Text("");
}
else {
return Text("Error occured");
}
}
);
return "";
}
Then in the TextField I want to show what is stored inside bio that should be the content of "bio.txt".
child: Text(
_ReadBio()== "" //always true if no error occured
? bio
: "Tell us something about you...",
),
But what is showed is the first bio value, I don't know why.

Answer 1

I strongly suggest you to read about FutureBuilder.
You are missing the point od FutureBuilder because its is a widget to place in a widget tree what you have done is placed on a function that returns a empty string.
Instead you can do it like this,
Future<Widget> _readAndBuildBioWidget(){
return FutureBuilder<String>(
future: _read(),
builder: (context, snapshot){
if (snapshot.hasData) {
bio=snapshot.data.toString(); //this isn't done
return Text(bio ?? "");
}
else {
return Text("Error occured");
}
}
);
return "";
}
#override
void build() {
return Scaffold(
child: _readAndBuildBioWidget(),
);
}
Or you can do as below,
class _HomeScreenState extends State<HomeScreen> {
var bio = "";
Future<String> _read() async {
try {
final file = await _localBio;
String body = await file.readAsString();
return body;
} catch (e) {
return "Can't read";
}
}
#override
void initState() {
_read().then((onValue) => bio = onValue);
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: Center(child: Text(bio ?? "")),
);
}
}
Note above code snippet I haven't tested. I just wanted to give a rough idea.