iPhone 4 width 320 height 480
iPhone 5/5s width 320 height 568
iPhone 6 width 375 height 667
iPhone 6 plus width 414 height 736
iOS 开发屏幕适配尺寸
iPhone 4 width 320 height 480
iPhone 5/5s width 320 height 568
iPhone 6 width 375 height 667
iPhone 6 plus width 414 height 736