UIPanGestureRecognizer and Simultaneous Recognizers

Once a line is selected during a long press, you want the user to be able to move that line around the screen by dragging it with a finger. So you need a gesture recognizer for a finger moving around the screen. This gesture is called panning, and its gesture recognizer subclass is UIPanGestureRecognizer.

Normally, a gesture recognizer does not share the touches it intercepts. Once it has recognized its gesture, it eats that touch, and no other recognizer gets a chance to handle it. In your case, this is bad: the entire pan gesture you want to recognize happens within a long press gesture. You need the long press recognizer and the pan recognizer to be able to recognize their ...

Get iOS Programming: The Big Nerd Ranch Guide now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.