android preference activity

Question

I have a preference activity and want that if one of its items is clicked it will start a background work and show a nice progress bar in foreground until the background task finishes. how to do it???

Code writtenis:

 public boolean onPreferenceClick(Preference preference) {
  showProgressDialog();
  new Thread(new Runnable() {
   public void run() {
    doSomething();
    hideProgressDialog();
   }       //Runnable.run()
  }).start();
  return false;
 }
});

But the above code is not showing progress dialog. and ANR error occurs.

Thanks.

Answer 1

Add following code in your activity class:

// Need handler for callbacks to UI Threads
    // For background operations
    final Handler mHandler = new Handler();

    // Create Runnable for posting results
    final Runnable mUpdateDone = new Runnable() {
        public void run() {
            progDialog.hide();      
            // Do your task here what you want after the background task is finished.           
        }
    };

Write following code in onPreferenceClick:

progDialog = ProgressDialog.show(AddPhoto.this, "", "Uploading Photo...");
            new Thread() {
                public void run() {
                    // Start your task here.....                                                        
                    mHandler.post(mUpdateDone);
                }
                }.start();

Let me know if doesn't work for you!

Answer 2

I have not implemented a progress dialog yet (plan to later today), but this example looks like a good one. I plan to use it myself. I note that it does a number of things that your code does not.