Receiver type 'CALayer' for instance message is a forward declaration錯誤

Receiver type 'CALayer' for instance message is a forward declaration 錯誤解決辦法

編譯錯誤:

Receiver type 'CALayer' for instance message is a forward declaration

解決辦法:

在出錯的.m文件中引入

#import<QuartzCore/QuartzCore.h>