最近刚开始做iPad版应用，但发现横版的时候宽高是反的，很别扭，所以在网上找了一段代码，能够很好的输出宽高
#define SCREEN_WIDTH ((([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationPortrait) || ([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationPortraitUpsideDown)) ? [[UIScreen mainScreen] bounds].size.width : [[UIScreen mainScreen] bounds].size.height) #define SCREEN_HEIGHT ((([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationPortrait) || ([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationPortraitUpsideDown)) ? [[UIScreen mainScreen] bounds].size.height : [[UIScreen mainScreen] bounds].size.width)
源自：http://stackoverflow.com/questions/7905432/how-to-get-orientation-dependent-height-and-width-of-the-screen