difference between `focusable` and `clickable`
Solution 1:
Clickable means that it can be clicked by a pointer device or be tapped by a touch device. Focusable means that it can gain the focus from an input device like a keyboard. Input devices like keyboards cannot decide which view to send its input events to based on the inputs itself, so they send them to the view that has focus.
Solution 2:
Focusable means ACTION_UP event will occur. It will gain it and it won't release it.
Clickable means ACTION_DOWN first and ACTION_UP at the end. It will gain and release it at the end.