OS 判断机型

开发中可能对不同的机型做出相应的适配

是否为iPhone6，6s,7

#ifndef iPhone6

#define iPhone6 ([UIScreen instancesRespondToSelector:@selector(currentMode)] ?  \\\\

CGSizeEqualToSize(CGSizeMake(750, 1334), [[UIScreen mainScreen] currentMode].size) : NO)

#endif

是否为iPhone6P，7P

#ifndef iPhone6P

#define iPhone6P ([UIScreen instancesRespondToSelector:@selector(currentMode)] ?  \\\\

CGSizeEqualToSize(CGSizeMake(1242, 2208), [[UIScreen mainScreen] currentMode].size) : NO)

#endif

```

是否为iPhone5系列机型

ifndef iPhone5

define iPhone5 ([UIScreen instancesRespondToSelector:@selector(currentMode)] ? \\

CGSizeEqualToSize(CGSizeMake(640, 1136), [[UIScreen mainScreen] currentMode].size) : NO)

endif

是否为iPhone4系列机型

ifndef iPhone4

define iPhone4 ([UIScreen instancesRespondToSelector:@selector(currentMode)] ? \\

CGSizeEqualToSize(CGSizeMake(640, 960), [[UIScreen mainScreen] currentMode].size) : NO)

endif

判断iOS系统版本

define iOS7Later ([UIDevice currentDevice].systemVersion.floatValue >= 7.0f)

define iOS8Later ([UIDevice currentDevice].systemVersion.floatValue >= 8.0f)

define iOS9Later ([UIDevice currentDevice].systemVersion.floatValue >= 9.0f)

define iOS9_1Later ([UIDevice currentDevice].systemVersion.floatValue >= 9.1f)