问题
I am modifying the "MoveMe" example from the apple web site. When my controller gets the "touchesMoved" message it moves the object being moved to the centre of the touch, because (pseudocode) object.center = touch.center. How can I store the offset of the initial touch so that if I start the touch/drag to the side my finger will stay on that spot while I drag it around?
回答1:
You can store target_view.frame in an instance variable when touchBegan message arrives.
回答2:
Can't you store that in an instance variable of your class?
来源：https://stackoverflow.com/questions/2438504/iphone-touchesbegan-and-touchesmoved-message-do-not-move-to-centre-of-to