Asynch thread stopping main UI thread

Question

Can anyone tell me why the following dialog box does not show until the asynchronous thread has finished. I cannot figure this one out. This is running in the main UI thread. Not sure why a new thread would affect the flow of the main UI thread

                dialog = new ProgressDialog(this);

                dialog.show();

                new Thread(new Runnable() {
                     public void run() {
                         while(imageLoader.isProcessing()) {}
                         doSomething();   
                     }
                 }).run();

Answer 1

You need to call the start() method of the anonymous Thread, not the run() method.

From the docs:

public void start(): Causes this thread to begin execution; the Java Virtual Machine calls the run method of this thread.