changed data type of Carrot's position from int to float
removed OnTouchEvent in the parent level
Revert "removed OnTouchEvent in the parent level"

This reverts commit 7bf96facd723073b8b5b75186930d2765d4a19af.
added isHit function
added selected function
changed to dp
added recordedTouchPtY for user's activity record
renamed variable
added state