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Keep getting “Instance of 'Future'” as output from json

Flutter: Fetch certain elements of a HTML pageIs there a way to get the Future from setMethodCallHandler?Loading a file using rootBundlefuture functions keep repeatingFlutter pushReplacementNamed().then() does not triggerHow to get primitive value from Future object (Future<int>) in flutter?How to use searchDelegate with future list from jsonCould not launch Instance of 'Future<String>'type 'Future<dynamic>' is not a subtype of type 'String'

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-1

I want to call a json api from https://jsonplaceholder.typicode.com/posts, but my output is "Instance of Future".

I obviously want the correct output to be 1. Check the link as to why it should be 1

getJson() is in a different .dart file(but same project) as the output.
I believe it is working correctly(since there is an output)

import 'package:http/http.dart' as http;
import 'dart:convert';

Future<List> getJson() async 
 String apiURL = "https://jsonplaceholder.typicode.com/posts";

 http.Response response = await http.get(apiURL);
 return json.decode(response.body);


Future getData(int i, String place) async 
 List _data = await getJson();

 return _data[i][place];

Then the output is

Text("This is the output $getData(0, "id")"

which results in
"Instance of 'Future<dynamic>'"

flutter

share|improve this question

asked Mar 27 at 10:52

RandyRandy

822 bronze badges

add a comment | 

-1

I want to call a json api from https://jsonplaceholder.typicode.com/posts, but my output is "Instance of Future".

I obviously want the correct output to be 1. Check the link as to why it should be 1

getJson() is in a different .dart file(but same project) as the output.
I believe it is working correctly(since there is an output)

import 'package:http/http.dart' as http;
import 'dart:convert';

Future<List> getJson() async 
 String apiURL = "https://jsonplaceholder.typicode.com/posts";

 http.Response response = await http.get(apiURL);
 return json.decode(response.body);


Future getData(int i, String place) async 
 List _data = await getJson();

 return _data[i][place];

Then the output is

Text("This is the output $getData(0, "id")"

which results in
"Instance of 'Future<dynamic>'"

flutter

share|improve this question

asked Mar 27 at 10:52

RandyRandy

822 bronze badges

add a comment | 

I want to call a json api from https://jsonplaceholder.typicode.com/posts, but my output is "Instance of Future".

I obviously want the correct output to be 1. Check the link as to why it should be 1

getJson() is in a different .dart file(but same project) as the output.
I believe it is working correctly(since there is an output)

import 'package:http/http.dart' as http;
import 'dart:convert';

Future<List> getJson() async 
 String apiURL = "https://jsonplaceholder.typicode.com/posts";

 http.Response response = await http.get(apiURL);
 return json.decode(response.body);


Future getData(int i, String place) async 
 List _data = await getJson();

 return _data[i][place];

Then the output is

Text("This is the output $getData(0, "id")"

which results in
"Instance of 'Future<dynamic>'"

flutter

share|improve this question

asked Mar 27 at 10:52

RandyRandy

822 bronze badges

import 'package:http/http.dart' as http;
import 'dart:convert';

Future<List> getJson() async 
 String apiURL = "https://jsonplaceholder.typicode.com/posts";

 http.Response response = await http.get(apiURL);
 return json.decode(response.body);


Future getData(int i, String place) async 
 List _data = await getJson();

 return _data[i][place];

Text("This is the output $getData(0, "id")"

flutter

flutter

share|improve this question

asked Mar 27 at 10:52

RandyRandy

822 bronze badges

share|improve this question

asked Mar 27 at 10:52

RandyRandy

822 bronze badges

asked Mar 27 at 10:52

RandyRandy

822 bronze badges

asked Mar 27 at 10:52

RandyRandy

822 bronze badges

2 Answers
2

active

oldest

votes

1

You can wrap your Text inside FutureBuilder - something like that:

FutureBuilder(builder: (BuildContext context, AsyncSnapshot<String> snapshot) 
 if (snapshot.hasData) return Text("This is the output $snapshot.data");
 else return Text("There is no output yet");
, future: getData(0, 'id'),);

share|improve this answer

answered Mar 27 at 11:00

Andrey TurkovskyAndrey Turkovsky

6,52944 gold badges2222 silver badges4747 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  The output text is in a Column(children: <Widgets>[Text(""), Text("")] Can you explain how to do it there?
  
  – Randy
  Mar 27 at 11:13
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  You can wrap the whole Column in FutureBuilder if you need this data for both Texts. If snapshot.hasData you return filled texts. In other case you can return what you want - some placeholder or just empty Container
  
  – Andrey Turkovsky
  Mar 27 at 11:29
  

  
  
  
  

add a comment | 

0

You need to await for the response
So instead of:

Text("This is the output $getData(0, "id")"

You need to do:

String _data = await getData(0, 'id');
Text('This is the output $_data');

share|improve this answer

answered Mar 27 at 10:55

knezzzknezzz

39622 silver badges77 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  My output is in a stateful widget like this class MyApp extends StatefulWidget @override _MyAppState createState() => _MyAppState(); class _MyAppState extends State<MyApp> Do I need to add something else? Because I'm writing String _data = await getData(0, 'id'); before the override in the _MyAppState class, but getting an error for await
  
  – Randy
  Mar 27 at 11:07
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Yeah that is fine, you could call this in initState(). But function that awaits has to be async so for example you could do this like: String _data; void showData() async getData(0, 'id').then((String s) if(mounted) setState(() => _data = s); ); Or you could just use FutureBuilder like different answer suggested
  
  – knezzz
  Mar 27 at 11:09
  
  

  
  
  
  

add a comment | 

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1

You can wrap your Text inside FutureBuilder - something like that:

FutureBuilder(builder: (BuildContext context, AsyncSnapshot<String> snapshot) 
 if (snapshot.hasData) return Text("This is the output $snapshot.data");
 else return Text("There is no output yet");
, future: getData(0, 'id'),);

share|improve this answer

answered Mar 27 at 11:00

Andrey TurkovskyAndrey Turkovsky

6,52944 gold badges2222 silver badges4747 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  The output text is in a Column(children: <Widgets>[Text(""), Text("")] Can you explain how to do it there?
  
  – Randy
  Mar 27 at 11:13
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  You can wrap the whole Column in FutureBuilder if you need this data for both Texts. If snapshot.hasData you return filled texts. In other case you can return what you want - some placeholder or just empty Container
  
  – Andrey Turkovsky
  Mar 27 at 11:29
  

  
  
  
  

add a comment | 

1

You can wrap your Text inside FutureBuilder - something like that:

FutureBuilder(builder: (BuildContext context, AsyncSnapshot<String> snapshot) 
 if (snapshot.hasData) return Text("This is the output $snapshot.data");
 else return Text("There is no output yet");
, future: getData(0, 'id'),);

share|improve this answer

answered Mar 27 at 11:00

Andrey TurkovskyAndrey Turkovsky

6,52944 gold badges2222 silver badges4747 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  The output text is in a Column(children: <Widgets>[Text(""), Text("")] Can you explain how to do it there?
  
  – Randy
  Mar 27 at 11:13
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  You can wrap the whole Column in FutureBuilder if you need this data for both Texts. If snapshot.hasData you return filled texts. In other case you can return what you want - some placeholder or just empty Container
  
  – Andrey Turkovsky
  Mar 27 at 11:29
  

  
  
  
  

add a comment | 

You can wrap your Text inside FutureBuilder - something like that:

FutureBuilder(builder: (BuildContext context, AsyncSnapshot<String> snapshot) 
 if (snapshot.hasData) return Text("This is the output $snapshot.data");
 else return Text("There is no output yet");
, future: getData(0, 'id'),);

share|improve this answer

answered Mar 27 at 11:00

Andrey TurkovskyAndrey Turkovsky

6,52944 gold badges2222 silver badges4747 bronze badges

FutureBuilder(builder: (BuildContext context, AsyncSnapshot<String> snapshot) 
 if (snapshot.hasData) return Text("This is the output $snapshot.data");
 else return Text("There is no output yet");
, future: getData(0, 'id'),);

share|improve this answer

answered Mar 27 at 11:00

Andrey TurkovskyAndrey Turkovsky

6,52944 gold badges2222 silver badges4747 bronze badges

answered Mar 27 at 11:00

Andrey TurkovskyAndrey Turkovsky

6,52944 gold badges2222 silver badges4747 bronze badges

answered Mar 27 at 11:00

Andrey TurkovskyAndrey Turkovsky

6,52944 gold badges2222 silver badges4747 bronze badges

0

You need to await for the response
So instead of:

Text("This is the output $getData(0, "id")"

You need to do:

String _data = await getData(0, 'id');
Text('This is the output $_data');

share|improve this answer

answered Mar 27 at 10:55

knezzzknezzz

39622 silver badges77 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  My output is in a stateful widget like this class MyApp extends StatefulWidget @override _MyAppState createState() => _MyAppState(); class _MyAppState extends State<MyApp> Do I need to add something else? Because I'm writing String _data = await getData(0, 'id'); before the override in the _MyAppState class, but getting an error for await
  
  – Randy
  Mar 27 at 11:07
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Yeah that is fine, you could call this in initState(). But function that awaits has to be async so for example you could do this like: String _data; void showData() async getData(0, 'id').then((String s) if(mounted) setState(() => _data = s); ); Or you could just use FutureBuilder like different answer suggested
  
  – knezzz
  Mar 27 at 11:09
  
  

  
  
  
  

add a comment | 

0

You need to await for the response
So instead of:

Text("This is the output $getData(0, "id")"

You need to do:

String _data = await getData(0, 'id');
Text('This is the output $_data');

share|improve this answer

answered Mar 27 at 10:55

knezzzknezzz

39622 silver badges77 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  My output is in a stateful widget like this class MyApp extends StatefulWidget @override _MyAppState createState() => _MyAppState(); class _MyAppState extends State<MyApp> Do I need to add something else? Because I'm writing String _data = await getData(0, 'id'); before the override in the _MyAppState class, but getting an error for await
  
  – Randy
  Mar 27 at 11:07
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Yeah that is fine, you could call this in initState(). But function that awaits has to be async so for example you could do this like: String _data; void showData() async getData(0, 'id').then((String s) if(mounted) setState(() => _data = s); ); Or you could just use FutureBuilder like different answer suggested
  
  – knezzz
  Mar 27 at 11:09
  
  

  
  
  
  

add a comment | 

You need to await for the response
So instead of:

Text("This is the output $getData(0, "id")"

You need to do:

String _data = await getData(0, 'id');
Text('This is the output $_data');

share|improve this answer

answered Mar 27 at 10:55

knezzzknezzz

39622 silver badges77 bronze badges

Text("This is the output $getData(0, "id")"

String _data = await getData(0, 'id');
Text('This is the output $_data');

share|improve this answer

answered Mar 27 at 10:55

knezzzknezzz

39622 silver badges77 bronze badges

answered Mar 27 at 10:55

knezzzknezzz

39622 silver badges77 bronze badges

answered Mar 27 at 10:55

knezzzknezzz

39622 silver badges77 bronze badges