I get a empty list when using then async and await functions

Question

it's the first time to write a Flutter code so i am confused, when i tring to get data from API, API working normaly and return a response with data but after that i need to save this data in a list and give it as a variable in another Function but it still empty

Widget number() {
  List number_list=[];
  get_number().then((value) {number_list=value.values.toList();
  print(number_list);// i am giting a list with Values 
   });


  print(number_list); // i am giting an empty list 
  return ListView(
    padding: const EdgeInsets.all(8),
    children: buttons(number_list),
  );
}

when using await follow the pattern Future<type> func(string parm) async{} then call the future using a promise func().then((value){}); — ListenSoftware Louise Ai Agent
– ListenSoftware Louise Ai Agent, Commented Mar 11, 2022 at 16:17

Mahdi Sharifi · Accepted Answer · 2022-03-11 16:20:20Z

1

You need to make your 'get_number' function an async function and then use 'await' to wait for the API's response to reach and then continue with creating variables and widgets out of the response. The code becomes like this:

Widget number() {
  List number_list=[];
  var value = await get_number();
  number_list=value.values.toList();

  return ListView(
    padding: const EdgeInsets.all(8),
    children: buttons(fleet_list),
  );
}

if you don't use 'await', your code won't wait for getting data from API.

answered Mar 11, 2022 at 16:20

Mahdi Sharifi

1861 silver badge3 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Halim Over a year ago

if i using await i have to use a async and after that i have to use Future and i wanna returen widget not Future Widget. but am using await in get_number() function

ListenSoftware Louise Ai Agent · Accepted Answer · 2022-03-11 16:29:21Z

0

try using a Future and a promise

List number_list=[];
  Future<List<int>> get_number() async{
    return [1,2,3,4];
  }
  
  foo(){
  get_number().then((values) {
      number_list=values;
      print(number_list);// i am giting a list with Values 
   });
  }
  
 foo();

answered Mar 11, 2022 at 16:29

ListenSoftware Louise Ai Agent

4,3432 gold badges31 silver badges39 bronze badges

Collectives™ on Stack Overflow

I get a empty list when using then async and await functions

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related