编写一个宏定义用判断当前设备是3.4寸还是4寸。#define iPhone5 ([UIScreeninstancesRespondToSelector:@selector(currentMode)] ?CGSizeEqualToSize(CGSizeMake(640, 1136), [[UIScreen mainScreen]currentMode].size) : NO)举个界面布局的例子：closeBtn.frame =CGRectMake(20, 0, 320, 460);if (iPhone5) {closeBtn.frame = CGRectMake(20, 0, 320,460+88);}