How to get Future callback in Flutter

Good day. I am a flutter beginner and now do some simple pratice.

I want: Press a button and call login api, if api response is success then go to main page.

but I don’t know how to get callback result.

viewModel

  Future<String> login(String account, String password) async {
    try {
      futureLogin = logon(account, password);
        await futureLogin.then((value) {

          print("key=${value.data.key}");//success print correct key

          return value.data.key;

        }).catchError((error) {
          print("error=$error");
        });
    } catch (error) {}

    return "";
  }

Button click event

onPressed: () async {
    var result = await viewModel.login(account, password);
    print("result=${result}");//print ""
}

I think that I can simply use await keyword to get my api result but not works.

How to solve it.

Any help will be appreciate.

>Solution :

Try using async await :

Future<String> login(String account, String password) async {
    try {
      futureLogin = logon(account, password);
      var value = await futureLogin;
      return value.data.key;
    } catch (error) {
        return "";
    }
  }

or using .then function add return key after calling futureLogin

return await futureLogin.then(......);