iOS-设备屏幕方向

iOS设备有Portrait (正向)，Upside down (颠倒)，Landscape Left （向左侧翻转）和 Landscape Right (向右侧翻转)四个方向.可以在AppDelegate可以根据设备来设置不同的方向：
<pre><code>- (UIInterfaceOrientationMask)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window { return UIInterfaceOrientationMaskPortrait; }</code></pre>

设备方向可以通过UIInterfaceOrientationMask枚举来设置:
<pre><code>typedef NS_OPTIONS(NSUInteger, UIInterfaceOrientationMask) { UIInterfaceOrientationMaskPortrait = (1 << UIInterfaceOrientationPortrait), UIInterfaceOrientationMaskLandscapeLeft = (1 << UIInterfaceOrientationLandscapeLeft), UIInterfaceOrientationMaskLandscapeRight = (1 << UIInterfaceOrientationLandscapeRight), UIInterfaceOrientationMaskPortraitUpsideDown = (1 << UIInterfaceOrientationPortraitUpsideDown), UIInterfaceOrientationMaskLandscape = (UIInterfaceOrientationMaskLandscapeLeft | UIInterfaceOrientationMaskLandscapeRight), UIInterfaceOrientationMaskAll = (UIInterfaceOrientationMaskPortrait | UIInterfaceOrientationMaskLandscapeLeft | UIInterfaceOrientationMaskLandscapeRight | UIInterfaceOrientationMaskPortraitUpsideDown), UIInterfaceOrientationMaskAllButUpsideDown = (UIInterfaceOrientationMaskPortrait | UIInterfaceOrientationMaskLandscapeLeft | UIInterfaceOrientationMaskLandscapeRight), } __TVOS_PROHIBITED;</code></pre>

如果项目中有些页面要求特定的方向旋转，可以在ViewController中设置:
<pre><code>`- (BOOL)shouldAutorotate {
return YES;
}

• (UIInterfaceOrientationMask)supportedInterfaceOrientations {
  return UIInterfaceOrientationMaskLandscapeLeft | UIInterfaceOrientationLandscapeRight;
  }`</code></pre>

默认方向设置:
<pre><code>- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation { return UIInterfaceOrientationPortrait; }</code></pre>

旋转通知:
<pre><code>[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(deviceOrientationChange:) name:UIDeviceOrientationDidChangeNotification object:nil];</code></pre>
<pre><code>`- (void)deviceOrientationChange:(NSNotification *)notification {

UIDeviceOrientation  orient = [UIDevice currentDevice].orientation;

switch (orient) {
    case UIDeviceOrientationPortrait:
        
        break;
    case UIDeviceOrientationLandscapeLeft:
        
        break;
    case UIDeviceOrientationPortraitUpsideDown:
        
        break;
    case UIDeviceOrientationLandscapeRight:
        
        break;
        
    default:
        break;
}

}`</code></pre>

状态栏变更通知:
<pre><code>[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(deviceOrientationChange:) name:UIApplicationDidChangeStatusBarOrientationNotification object:nil];</code></pre>
<pre><code>`- (void)statusBarOrientationChange:(NSNotification *)notification{

UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];

if (orientation == UIInterfaceOrientationLandscapeRight) {
    
}

if (orientation ==UIInterfaceOrientationLandscapeLeft) {

}

 if (orientation == UIInterfaceOrientationPortrait){
     
 }

if (orientation == UIInterfaceOrientationPortraitUpsideDown){

}

}`</code></pre>