iPhone应用程序自定义UIWindow错误框架在iPad横向方向

Question

我正在使用自定义UIWindow编写iPhone应用程序。（xCode6.1，iOS8.1）

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{
    // Override point for customization after application launch.
    application.statusBarOrientation = UIInterfaceOrientationLandscapeRight;
    CGRect bounds = [[UIScreen mainScreen] bounds];
    _window = [[UIWindow alloc] initWithFrame:CGRectMake(0, 0, bounds.size.height, bounds.size.width)];
    [_window setBackgroundColor:[UIColor greenColor]];
    [_window makeKeyAndVisible];
    return YES;
}

它仅针对iPhone，仅限景观。所有iPhone设备都可以正常工作，但是当它在iPad上运行时，UIWindow框架就会崩溃。

有什么建议吗？