Question

I would like to know how could i block the dial, home , back and the end call button on an android device.

I know this is possible because there is an application : TheftAware which does block all the buttons so they have no effect at all.

And I also would like to know how to make a dialog window or any kind of window which would stay on top no matter what (this is also done in theftaware).

They are also able to block(hide) the call screen… does someone know how are they doing that ?

Note: Does all this means that android is not that secure after all ?

Answer 1

I just wanted to clear up a few bits of information here.

The code example from BeRecursive is incorrect in a few ways. As already noted, it won’t block the Home button, but it has other problems:

1. In order to consume the event so the
   rest of the Android framework won’t
   act upon it, you need to return
   true from the onKeyDown handler,
   not false. The contract is that
   true means the application handled
   the event and the framework should
   not perform the default key event
   handling. (Praveen’s code example also has the same issue).

2. Starting from Android 1.5 and later,
   the Android framework moved the
   action activation from onKeyDown
   to onKeyUp. So you’ll also need
   to implement the blocking in the
   onKeyUp handler, not just the
   onKeyDown handler.

3. It is possible to block the
   KeyEvent.KEYCODE_CALL button using
   this technique, but not the
   KeyEvent.KEYCODE_ENDCALL button.
   This appears to be for security
   reasons.

Finally, the trick of setting WindowManager.LayoutParams.TYPE_SYSTEM_ALERT didn’t have any effect for me in terms of actually blocking any of the hardware buttons. It might be useful for supressing popups from other applications, but I haven’t explored this fully.

There’s lots of good information from the Android team in this blog post.