Changed background of the application to custom image. Added a button
with custom icon (power button). Now trying to make the image button
highlighted
when clicked.
Finally, I managed to make the imageButton highlight when clicked.
The problem is that the method AddListenerOnGivenButton works
only with class Button not ImageButton (ImageButton cannot be cast into
Button). That's why I will try to make an ordinary button with a
background
image.
Now the Power button with custom icon works (both animation and
listener).
Power button is an ImageButton and there are two "AddListener" methods.
I have custom images also for volume up and down.
All the buttons (except Power) are from the same style (black, rounded
square).
All the buttons highlight when clicked. I'm going to find a power button
which better fits into the current app style.