how to wait for Android runOnUiThread to be finished?

Question

I have a worker thread that creates a runnable object and calls runOnUiThread on it, because it deals with Views and controls. I\'d like to use the result of the work of the

Answer 1

A solution might be to leverage Java's FutureTask which has the benefit that someone else has already dealt with all the potential concurrency issues for you:

public void sample(Activity activity) throws ExecutionException, InterruptedException {
    Callable callable = new Callable() {
        @Override
        public Void call() throws Exception {
            // Your task here
            return null;
        }
    };

    FutureTask task = new FutureTask<>(callable);
    activity.runOnUiThread(task);
    task.get(); // Blocks
}

You can even return a result from the main thread by replacing Void with something else.