抽取UIButton分类及UIBarButtonItem分类

• 提供接口快速实现对button和barButtonItem的创建

• 为了可扩展性和复用性,要有面向接口编程而不是面向实现编程

• .h文件:

  @interface UIButton (WYButton)
  
  - (instancetype)initWithImage:(UIImage *)image selectedImage:(UIImage *)selectedImage addTarget:(id)target action:(SEL)action;
  
  - (instancetype)initWithImage:(UIImage *)image highlightedImage:(UIImage *)highlightedImage addTarget:(id)target action:(SEL)action;
  
  + (instancetype)buttonWithImage:(UIImage *)image selectedImage:(UIImage *)selectedImage addTarget:(id)target action:(SEL)action;
  
  + (instancetype)buttonWithImage:(UIImage *)image highlightedImage:(UIImage *)highlightedImage addTarget:(id)target action:(SEL)action;
  
  @end
  

• .h文件:

  @interface UIBarButtonItem (WYItem)
  
  + (instancetype)itemWithWithImage:(UIImage *)image highlightedImage:(UIImage *)highlightedImage addTarget:(id)target action:(SEL)action;
  
  + (instancetype)itemWithWithImage:(UIImage *)image selectedImage:(UIImage *)selectedImage addTarget:(id)target action:(SEL)action;
  
  @end