Use the layout xml attribute splitMotionEvents="true" or the ViewGroup
method setMotionEventSplittingEnabled(true) to enable motion event
splitting. Rules for splitting are as follows:
* Splitting is enabled per ViewGroup. When splitting is enabled any
MotionEvent dispatched to that ViewGroup can potentially be split
into several and dispatched to children independently.
* Each pointer is assigned a target child view when the ACTION_DOWN or
ACTION_POINTER_DOWN event is received. That will be the pointer's
target until it goes up, the target returns false from onTouchEvent,
or the MotionEvents are intercepted.
* Multiple pointers may be assigned to the same target. All pointer
data sent to a target are bundled into a single MotionEvent. Child
views do not need to be aware that splitting has occurred.
Change-Id: I993f838e2f6b455da9812f4742a016dfcd1c4cc9
2b342f0a76