What is the easiest way to open a keyboard in a listviewactivity?

Question

What is the easiest way to - for instance when the search button is pressed in a ListViewActivity" - to open a keyboard and pass the input to the ListViewActivitiy when setTextFilterEnabled(true); is set?

@Override public boolean onKeyDown(int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_SEARCH) { // HOW DO I OPEN A KEYBOARD HERE - IF POSSIBLE? return true; }

    return false;
};