屏幕适配相关

1.不同大小宏定义：

#define iPhone4inch ([UIScreen mainScreen].bounds.size.height == 568.0 && [UIScreen mainScreen].bounds.size.width == 320) ? YES : NO  
  
#define iPhone3p5inch ([UIScreen mainScreen].bounds.size.height == 480.0 && [UIScreen mainScreen].bounds.size.width == 320) ? YES : NO  
  
#define iPhone4p7inch ([UIScreen mainScreen].bounds.size.height == 667.0 && [UIScreen mainScreen].bounds.size.width == 375) ? YES : NO  
  
#define iPhone5p5inch ([UIScreen mainScreen].bounds.size.height == 736.0 && [UIScreen mainScreen].bounds.size.width == 414) ? YES : NO