dart - 如何完成 future ？

Question

我正在搜索类似以下内容的内容，其中我从方法中返回一个对象，该对象可以等待，并从其原始函数完成:

Future<dynamic> customFunction() {
    // The following class does not exist, but I am searching for a class that would fill that gap.
    FutureWithCompletion future = FutureWithCompletion();
    () async { // A callback that represents the usecase.
      // some computation
      future.completeWith('something');
    }
    return future;
}

/// This function accesses [customFunction].
/// It should print out "something" once the computation is done.
anotherFunction() async => print(await customFunction());

Answer 1

您需要使用Completer:

Future<String> method() {
  final completer = Completer<String>();
  Timer(Duration(seconds: 5), () => completer.complete('result'));
  return completer.future;
}