Disable a whole activity from user action

If you need to disable event processing for a period of time (for instance, while you run an animation, show a waiting dialog), you can override the activity's dispatch functions.

To disable touch/clicks on any buttons, add these members/functions to your activity:

protected boolean enabled = true;

public void enable(boolean b) {
    enabled = b;
}

@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
    return enabled ? 
        super.dispatchTouchEvent(ev) : 
        true;        
}

Then just call enable(true/false) when you need to disable and enable the activity's normal event handling.

Use AsyncTask with ProgressDialog bundled.

1. AsyncTask

2. Progress Dialog

another useful example:

http://www.screaming-penguin.com/node/7746

In order to block user touch events, use:

getWindow().setFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE,
WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);

To get touch events back, use:

getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);

EDIT: If you want to add a feature of disable and greyed out display, you need to add in your xml layout file a linear layout that fills the parent. Set its background to #B0000000 and its visibilty to Gone. Than programicly set its visibility to Visible.