Question

Folks,

Here is a simplified code for my background thread:

    public class MyThread extends Thread {
      private Handler _handler;

      public void run() {
         Looper.prepare();
         this._handler = new Handler();
         Looper.loop();
      }

      public void DoSomething() {
         if (!this.isAlive()) {
            this.start();
         }

         this._handler.post(blah);
      }
    }

The problem I have is that the background thread may not have yet created the handler object when post() call is made. Essentially, I need a wait loop for the handler object to be initialized. What is generated accepted method of doing this under Android?

Thank you in advance for your help.

Regards,
Peter

Answer 1

You can set a flag after you initialize the Handler and wait for this flag before calling post.

An easy way to wait for a flag in a concurrent system is with a CountDownLatch. It would start at 1 and decrement after the Handler is initialized. Check out the details here:
http://download.oracle.com/javase/1,5,0/docs/api/java/util/concurrent/CountDownLatch.html