For example, send a backspace key to the edit text control to remove a character or send a char code like 112 to append a character in the edittext control programmatically.
To send a simulated backspace key press to an EditText you have to send both key press and release events. Like this:
mEditText.dispatchKeyEvent(new KeyEvent(0, 0, KeyEvent.ACTION_DOWN,
KeyEvent.KEYCODE_DEL, 0));
mEditText.dispatchKeyEvent(new KeyEvent(0, 0, KeyEvent.ACTION_UP,
KeyEvent.KEYCODE_DEL, 0));
This can be used to send any other key code, not just delete.