ios,判斷目前使用的device為ipad or iphone

【環境：xCode4.3.2 , ios5.0 , USE ARC】

以下是library中所註明的資訊，可在xcode中對使用的關鍵字userInterfaceIdiom按下command+滑鼠左鍵去檢視

typedef enum {

#if __IPHONE_3_2 <= __IPHONE_OS_VERSION_MAX_ALLOWED

    UIUserInterfaceIdiomPhone,           // iPhone and iPod touch style UI

    UIUserInterfaceIdiomPad,             // iPad style UI

#endif

} UIUserInterfaceIdiom;

/* The UI_USER_INTERFACE_IDIOM() macro is provided for use when deploying to a version of the iOS less than 3.2. If the earliest version of iPhone/iOS that you will be deploying for is 3.2 or greater, you may use -[UIDevice userInterfaceIdiom] directly.

 */

#define UI_USER_INTERFACE_IDIOM() ([[UIDevice currentDevice] respondsToSelector:@selector(userInterfaceIdiom)] ? [[UIDevice currentDevice] userInterfaceIdiom] : UIUserInterfaceIdiomPhone)

<以下使用範例>

self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 
if ([[UIDevice currentDevice]userInterfaceIdiom]==UIUserInterfaceIdiomPhone) {
UIViewController*  IPhoneViewController1=[[UIViewController  alloc]init];
self.window.rootViewController=  IPhoneViewController1;
}
else if ([[UIDevice currentDevice]userInterfaceIdiom]==UIUserInterfaceIdiomPad) 
{
UIViewController*  IPadViewController1=[[UIViewController  alloc]init];
self.window.rootViewController=  IPadViewController1;
} 

or if you have nib file, you can type

[[ViewController alloc] initWithNibName:@"ViewController_iPhone" bundle:nil];

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