ViewController respondsToSelector error solution, mvcviewcontroller

ViewController respondsToSelector error solution, mvcviewcontroller

Cause analysis: (analyze from others' blogs)
A public class or a control provided by the system has a delegate method. When the container class that creates this public control has been destroyed,
The service corresponding to this control is carried out in other run loop. when the control is destroyed or status notification is required
This problem occurs when the delegate pointer goes to the notification.

Problems encountered in the project:

Textview is in the focus state (the keyboard pops up), and then click the cancel button to pop the current uiviewcontroller. At this time, the keyboard recycling operation of textview is triggered first, in the keyboard reclaim method, the contentOffset of the scrollview is reset. When the contentOffset of the scrollview is set, the delegate (VC) call is triggered continuously, and the VC has been released, so there was a crash. Set the delegate to null in dealloc (the delegate of iOS6 tableview should also be empty)