iOS development expands the potential error of drag gestures in-xib

iOS development expands the potential error of drag gestures in-xib

First, error description

Customizing a class to encapsulate a toolbar

Build the Xib and add a drag gesture.

　　

Code for the host controller: loading toolbars

Encapsulating toolbars and gesture-dragging listening events

　　

At this time to run the program, the program directly crashes, error is as follows:

　

Note: Gestures do not have a Superview method, Superview is UIView method, indicating that we mistakenly put the gesture object as a uiview to use.

Debug to see why the problem occurred:

　　

Why the problem occurred:

　　

Description: The object that was taken out by Lastobject is a gesture, not a xib, so the above error occurs.

Change the Lastobject to Firstobject, and if necessary, print out all the objects in the array to view.　

iOS development expands the potential error of drag gestures in-xib