presentModalViewController推出方向问题

UIViewController *modalViewController = [[UIViewController alloc] init];

[modalViewControllersetModalTransitionStyle:UIModalTransitionStyleFlipHorizontal];

// typedef enum {

// UIModalTransitionStyleCoverVertical = 0,

// UIModalTransitionStyleFlipHorizontal,

// UIModalTransitionStyleCrossDissolve,

//#if __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_3_2

// UIModalTransitionStylePartialCurl,

//#endif

// } UIModalTransitionStyle;

[selfpresentModalViewController:modalViewControlleranimated:YES];