[Solved ]Converting a Future variable to a normal String in the Flutter build Method

Question

I am trying to use http-requests to get Json data of a devicemanagement webserver. the webserver works wonderfully and is viewable publicly. the Database, Webserver and the Webapp are all in my cloud and working perfectly.

The Problem: i cant use "Future" as a String. i also cannot await the Future.

    class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title:'Json Text',
      home: Scaffold(
        appBar: AppBar(
          title:Text('JsonText') // yup, this appears.
        ),
        body: Center(
          child: Text((getText().toString())) // Returns "Instance of 'Future<String>'" should be "New"
        ),
    ));
  }

i cannot "await getText()" since it is the function that builds the Flutter App, it simply returns an error if i try.

i have tried quite alot: return await m // doesnt work, still returns a Future Object. tried changing the return type to String // doesnt work, async throws an error.

Future<Modell> getJson() async {
    // simple request for a single modell
    var simple_response = await http.get("http://35.207.119.142:443/api/commands/1010"); // my url here
    print("Station 3");

    // this should be checked after EVERY http.get
    if (simple_response.statusCode != 200) {
      print("something went wrong");
    } else {
      print("everything is correct"); // In my Case, this does work.
    }

    print("Station 4");

    Modell m = Modell.fromJson(jsonDecode(simple_response.body));
    print("Station 5");
    return m;
  }

  Future<String> getText() async {
    print("Station 2");
    Modell m = await getJson();
    print("Station 6");
    print(m.modell); // Properly returns: "New". thats what it should be.
    print("Endstation");
    return m.modell; // This is what i need Help With.
  }

TLDR: what i need is an Instance of "String" instead of "Future", and i cannot use "await" since the build function cant do that.

This code is in Flutter, and i am supposed to make an App for a Webserver reachable at: 35.207.119.142 (When i turn it on.)

in order to better use this code, im leaving the webserver on for about a day.

here is the entirety of my Code: Actual App: https://del.dog/tetengoqex.txt Provided API (bad): https://del.dog/liwecramyd.txt Actual Webserver API: https://del.dog/v/uwestol (this contains a link to github)

so once again: my question is: how do i get the content of: m.model (m is an Instance of a Modell):

class Modell {
  int geraeteID;
  String modell;
  int baujahr;
  String seriennummer;
  bool verfuegbar;
  String historie;
  String datumAusleihe;
  String ausgeliehenAn;
  String bemerkung;
  bool aktiv;

I Thank you for contemplating the solution of this problem, i wish you a good day.

• Cuboid404

Solution Code: https://del.dog/garfapovil.txt

Solution: Use the FutureBuilder Widget. while it wasnt that easy to use, it was better than using .this()

home: Scaffold(
        appBar: AppBar(
          title:Text('JsonText') // yup, this appears.
        ),
        body: Center(
          child: FutureBuilder(
              future: getText(),
            builder: (context, snapshot) {
              if (snapshot.hasData) {
              return Text(snapshot.data,style: Theme.of(context).textTheme.headline);
              } else if (snapshot.hasError) {
              return Text("${snapshot.error}",style: Theme.of(context).textTheme.headline);
              } else {
                return CircularProgressIndicator();
              }})

Answer 1

Use a FutureBuilder widget.

FutureBuilder<Modell>(
        future: getJson(), 
        builder: (BuildContext context, AsyncSnapshot<Modell> snapshot) {
          // make sure `snapshot.hasData`, then use `snapshot.data`, which is your instance of `Modell`
        },
      );