//0-255的随机数
#define randint arc4random() % 256
//随机色
#define randColor [UIColor colorWithRed:randint/255.0 green:randint/255.0 blue:randint/255.0 alpha:1.0]
PCH文件常用宏定义
原文：http://www.cnblogs.com/xj76149095/p/5049503.html
