CODEWITHSUNDEEP
flutterdartasynchronousasync-awaitfuture
Xkfkxkmkodm28299
Xkfkxkmkodm28299

Reputation: 11

Best way to get value from future in constructor in dart

what ways you suggest for getting value from future in object constructor ?

class F{
late SomeObj<t> _obj;
F(){
 () async{
    _obj = await someFuture();
  }.call();
}
 somefunc() => doing something with _obj

}

but this doesn't gave me right res in the right time, Other ways for this situation?

Upvotes: 1

Views: 720

Answers (1)

jamesdlin
jamesdlin

Reputation: 89955

Here are two possible approaches:

  • Make your class's constructor private and force callers to instantiate your class via an asynchronous static method. From the perspective of callers, there is little difference between calling a static method and a named constructor.

    class F {
  late SomeObj<T> _obj;

  F._();

  static Future<F> create() async {
    var f = F._();
    f._obj = await someFuture();
    return f;
  }

  Object? someFunc() => doSomethingWith(_obj);
}

  • Explicitly make everything that depends on the asynchronous value also asynchronous. If _obj is initialized asynchronously, then _obj should be a Future. If someFunc depends on _obj, then someFunc should return a Future.

    class F {
  Future<SomeObj<T>> _obj;

  F() : _obj = someFuture();

  Future<Object?> someFunc() async => doSomethingWith(await _obj);
}

Upvotes: 1

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