async-tools

Tools to handle concurrent execution and asynchronous events

This is a collection of tools for Java in general and Android in particular to manage asynchronous events.

Requirements

• classes in org.dmfs.asynctools.android are Android specific and require the Android SDK

Example code

Join AsyncTasks in Android

AsyncTasks in Android can be used to execute short-running jobs in the background. Since the actual threads are hidden you can't join those AsyncTasks easily (to perfom another operation once all tasks have finished).

JoinAsyncTasks provides a convenient way to do this like so:

	private final OnJoinAsyncTasksCallback onJoinTasks = new OnJoinAsyncTasksCallback()
	{
		@Override
		public void onJoinAsyncTasks(int id)
		{
			// do whatever you want to do when all AsyncTasks have finished.
		}
	};

	...

	private void someMethod()
	{
		...
		JoinAsyncTask.join(onJoinTasks, asyncTask1, asyncTask2, asyncTask3);
		...
	}

This executes the calls the callback once asyncTask1, asyncTask2 and asyncTask3 have finished.

Note: You need to ensure that you keep a reference to the callback, otherwise it might get garbage collected and not executed. JoinAsyncTask only stores a WeakReference of the callback to avoid Context leaks. To be sure, just let your Activity or Fragment implement OnJoinAsyncTasksCallback and pass it as callback. See below for an example:

	public class SomeActivity extends Activity implements OnJoinAsyncTasksCallback
	{

		...

		@Override
		public void onJoinAsyncTasks(int id)
		{
			// do whatever you want to do when all AsyncTasks have finished.
		}

		...

		private void someMethod()
		{
			...
			JoinAsyncTask.join(this, 1, asyncTask1, asyncTask2, asyncTask3);
			...
		}
	};

License

Copyright (c) Marten Gajda 2014, licensed under Apache 2 (see LICENSE).