Provides the ability to create Task-based APIs.

Use a TaskCompletionSource to set a result or exception on a Task returned from an asynchronous API:

 public class MarcoPolo {
   public static Task<String> marco(int delay) {
     TaskCompletionSource<String> taskCompletionSource = new TaskCompletionSource<>();

     new Handler().postDelayed(() -> taskCompletionSource.setResult("polo"), delay);

     return taskCompletionSource.getTask();
   }
 }
 

And then your APIs can be used as any other Task-consuming APIs:

 public class MyActivity extends Activity {
   @Override
   public void onStart() {
     super.onStart();

     marco(1000).addOnCompleteListener(
         task -> Log.d(TAG, "got message after one second: " + task.getResult()));
   }
 }