Android context leaks in AsyncTask

Question

If I interpret this article correctly, passing the activity context to AsyncTasks is a potential leak, as the activity might be destroyed while the task is still running.

How do you deal with this in AsyncTasks that are not inner clases and need access to resources or to update the UI?

Additionally, how can you avoid leaking the context if you need references to progress dialogs to dismiss them?

Answer 1

If I understand your question correctly: Java's WeakReference or SoftReference class is a good fit for this type of situation. It will allow you to pass the context to the AsyncTask without preventing the GC from freeing the context if necessary.

The GC is more eager when collecting WeakReferences than it is when collecting SoftReferences.

instead of:

FooTask myFooTask = new FooTask(myContext);

your code would look like:

WeakReference<MyContextClass> myWeakContext = new WeakReference<MyContextClass>(myContext);
FooTask myFooTask = new FooTask(myWeakContext);

and in the AsyncTask instead of:

myContext.someMethod();

your code would look like:

myWeakContext.get().someMethod();