iOS 强制横屏

在iOS5.1 和 之前的版本中， 我们通常利用 shouldAutorotateToInterfaceOrientation: 来单独控制某个UIViewController的旋屏方向支持，比如：
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation  
{  
   return (interfaceOrientation == UIInterfaceOrientationPortrait);  
}  

但是在iOS6中，这个方法被废弃了，使用无效。
shouldAutorotateToInterfaceOrientation:
Returns a Boolean value indicating whether the view controller supports the specified orientation. (Deprecated in iOS 6.0. Override the supportedInterfaceOrientations andpreferredInterfaceOrientationForPresentation methods instead.)

实践后会发现，通过supportedInterfaceOrientations的单独控制是无法锁定屏幕的。
-(NSUInteger)supportedInterfaceOrientations  
{  
   return UIInterfaceOrientationMaskPortrait;  
} 

多次实验后总结出控制屏幕旋转支持方向的方法如下：
子类化UINavigationController，增加方法
- (BOOL)shouldAutorotate  
{  
   return self.topViewController.shouldAutorotate;  
}
- (NSUInteger)supportedInterfaceOrientations  
{  
   return self.topViewController.supportedInterfaceOrientations;  
}  

并且设定其为程序入口，或指定为 self.window.rootViewController
随后添加自己的view controller，如果想禁止某个view controller的旋屏：（支持全部版本的控制）
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation  
{  
   return (interfaceOrientation == UIInterfaceOrientationPortrait);  
} 
-(BOOL)shouldAutorotate  
{  
   return NO;  
}  

-(NSUInteger)supportedInterfaceOrientations  
{  
   return UIInterfaceOrientationMaskPortrait;  
} 

如果想又开启某个view controller的全部方向旋屏支持：
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation  
{  
   return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);  
} 
-(NSUInteger)supportedInterfaceOrientations  
{  
   return UIInterfaceOrientationMaskAllButUpsideDown;  
} 
-(BOOL)shouldAutorotate  
{  
   return YES;  
} 

从而实现了对每个view controller的单独控制。
顺便提一下，如果整个应用所有view controller都不支持旋屏，那么干脆：
- (NSUInteger)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window  
{  
    return UIInterfaceOrientationMaskPortrait;  
}

此外 如果如果希望在进入某个ViewController时就是横屏 那么你可以在

 - (void)viewWillAppear:(BOOL)animated

{

   [superviewWillAppear:animated];

CGFloat duration = [UIApplicationsharedApplication].statusBarOrientationAnimationDuration;

   [UIViewbeginAnimations:nilcontext:nil];

   [UIViewsetAnimationDuration:duration];

self.navigationController.view.transform = CGAffineTransformIdentity;

self.navigationController.view.transform = CGAffineTransformMakeRotation(M_PI*(90)/180.0);

self.navigationController.view.bounds = CGRectMake(0, 0, 1024, 768);

   [UIViewcommitAnimations];

   [[UIApplicationsharedApplication] setStatusBarOrientation: UIInterfaceOrientationLandscapeRightanimated:YES];

}

转载：http://zqlswt1314.blog.51cto.com/3014999/1282672