iOS屏幕旋转与锁屏

在做视频开发时遇到屏幕旋转问题,其中涉及到 StatusBar、 UINavigationController、UITabBarController 、UIViewcontroller。

在设备锁屏下的整体效果图

主要涉及以下4点：
- 横竖屏的旋转
- 屏幕旋转相应改变视图位置
- 旋转时状态栏的隐藏与显示
- 锁屏

1、横竖屏旋转

第1步：

 -(UIInterfaceOrientationMask)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window {//    NSLog(@"0000000---------%@",NSStringFromClass([[self topViewController] class]));
//    if ([NSStringFromClass([[self topViewController] class]) isEqualToString:@"FirstViewController"]) {//        //横屏
//        return UIInterfaceOrientationMaskLandscapeRight;
//    }
//    //竖屏
//    return UIInterfaceOrientationMaskPortrait;NSUInteger orientations = UIInterfaceOrientationMaskAllButUpsideDown;if(self.window.rootViewController){//取出当前显示的控制器UIViewController *presentedViewController = [self topViewControllerWithRootViewController:self.window.rootViewController];//按当前控制器支持的方向确定旋转方向(将旋转方向重新交给每个控制器自己控制)NSLog(@"%s, line = %d",__FUNCTION__,__LINE__);orientations = [presentedViewController supportedInterfaceOrientations];}return orientations;
}
//获取界面最上层的控制器
//- (UIViewController*)topViewController {//    NSLog(@"%s, line = %d",__FUNCTION__,__LINE__);
//    return [self topViewControllerWithRootViewController:[UIApplication sharedApplication].keyWindow.rootViewController];
//}
//一层一层的进行查找判断
- (UIViewController*)topViewControllerWithRootViewController:(UIViewController*)rootViewController {NSLog(@"%s, line = %d",__FUNCTION__,__LINE__);if ([rootViewController isKindOfClass:[UITabBarController class]]) {UITabBarController* tabBarController = (UITabBarController*)rootViewController;NSLog(@"Tabbar:%@",NSStringFromClass([tabBarController.selectedViewController class]));return [self topViewControllerWithRootViewController:tabBarController.selectedViewController];} else if ([rootViewController isKindOfClass:[UINavigationController class]]) {UINavigationController* nav = (UINavigationController*)rootViewController;NSLog(@"nav:%@",NSStringFromClass([nav.visibleViewController class]));return [self topViewControllerWithRootViewController:nav.visibleViewController];} else if (rootViewController.presentedViewController) {NSLog(@"present:%@",NSStringFromClass([rootViewController.presentationController class]));UIViewController* presentedViewController = rootViewController.presentedViewController;return [self topViewControllerWithRootViewController:presentedViewController];} else {NSLog(@"root:%@",rootViewController);return rootViewController;}
}

代码中通过 -(UIInterfaceOrientationMask)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window 方法将控制器交给自己控制，该方法默认值为Info.plist中配置的Supported interface orientations项的值。

第2步：在各控制器设置支持的方向

//是否允许旋转(默认允许)
- (BOOL)shouldAutorotate {return YES;
}- (UIInterfaceOrientationMask)supportedInterfaceOrientations{//允许旋转的方向return UIInterfaceOrientationMaskAll;
}

其中- supportedInterfaceOrientations 方法在 iPad 中默认取值为 UIInterfaceOrientationMaskAll，即默认支持所有屏幕方向；而 iPhone 跟 iPod Touch 的默认取值为 UIInterfaceOrientationMaskAllButUpsideDown，即支持除竖屏向下以外的三个方向。
在设备屏幕旋转时，系统会调用 - shouldAutorotate 方法检查当前界面是否支持旋转，只有 - shouldAutorotate返回 YES 的时候，- supportedInterfaceOrientations 方法才会被调用，以确定是否需要旋转界面。
这个是 TabbarController 中设置的,它会影响关联的 UIViewController 的支持方向，需要在 UIViewController 中进一步设置

//此方法来控制能否横竖屏 控制锁屏
- (UIInterfaceOrientationMask)supportedInterfaceOrientations {NSLog(@"%s, line = %d",__FUNCTION__,__LINE__);UIInterfaceOrientationMask inter;if (_lockScreen) {switch (_lockOrientation) {case 1:inter = UIInterfaceOrientationMaskPortrait;break;case 2:inter = UIInterfaceOrientationMaskPortraitUpsideDown;break;case 3:inter = UIInterfaceOrientationMaskLandscapeRight;break;case 4:inter = UIInterfaceOrientationMaskLandscapeLeft;break;default:inter = UIInterfaceOrientationMaskAll;break;}} else {inter = UIInterfaceOrientationMaskAll;}//支持全部方向return inter;
}

第3步：强制转换控制器方向

- (void)setInterOrientation:(UIInterfaceOrientation)orientation {if ([[UIDevice currentDevice] respondsToSelector:@selector(setOrientation:)]) {SEL selector             = NSSelectorFromString(@"setOrientation:");NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:[UIDevice instanceMethodSignatureForSelector:selector]];[invocation setSelector:selector];[invocation setTarget:[UIDevice currentDevice]];int val                  = orientation;// 从2开始是因为0 1 两个参数已经被selector和target占用[invocation setArgument:&val atIndex:2];[invocation invoke];}
}

这样就可以完成横竖屏的切换。

2、屏幕旋转相应改变视图位置

这里先扩展UIDeviceOrientation & UIInterfaceOrientation的知识

UIDeviceOrientation 设备的物理方向
UIDeviceOrientation即我们手持的移动设备的Orientation，是一个三围空间,有六个方向,通过[UIDevice currentDevice].orientation获取当前设备的方向。

typedef NS_ENUM(NSInteger, UIDeviceOrientation) {UIDeviceOrientationUnknown,UIDeviceOrientationPortrait,            UIDeviceOrientationPortraitUpsideDown,  // Device oriented vertically, home button on the top 竖屏向下，即头在下，Home 键在上UIDeviceOrientationLandscapeLeft,       // Device oriented horizontally, home button on the right 横屏头在左，Home键在右UIDeviceOrientationLandscapeRight,      // Device oriented horizontally, home button on the left  横屏头在右，Home键在左UIDeviceOrientationFaceUp,              // Device oriented flat, face upUIDeviceOrientationFaceDown             // Device oriented flat, face down
} ;

UIInterfaceOrientation界面的显示方向

UIInterfaceOrientation即我们看到的视图的Orientation，可以理解为statusBar所在的方向，是一个二维空间，有四个方向, 通过[UIApplication sharedApplication].statusBarOrientation即状态栏的方向获取当前界面方向。

// Note that UIInterfaceOrientationLandscapeLeft is equal to   UIDeviceOrientationLandscapeRight (and vice versa).
// This is because rotating the device to the left requires rotating the content to the right.
typedef NS_ENUM(NSInteger, UIInterfaceOrientation) {UIInterfaceOrientationUnknown            = UIDeviceOrientationUnknown,UIInterfaceOrientationPortrait           = UIDeviceOrientationPortrait,UIInterfaceOrientationPortraitUpsideDown = UIDeviceOrientationPortraitUpsideDown,UIInterfaceOrientationLandscapeLeft      = UIDeviceOrientationLandscapeRight,UIInterfaceOrientationLandscapeRight     = UIDeviceOrientationLandscapeLeft
}

UIInterfaceOrientationMask支持的方向

// iOS 6 之后用于控制界面的枚举值
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),
}

由上可以发现：

iOS 6 及之后版本使用的UIInterfaceOrientationMask类型来控制屏幕屏幕方向，该类型也新增加了几个枚举取值，可用一个枚举取值来代表多个屏幕方向，使用起来更方便。
注意在UIInterfaceOrientation中有注释 Note that UIInterfaceOrientationLandscapeLeft is equal to UIDeviceOrientationLandscapeRight (and vice versa).
This is because rotating the device to the left requires rotating the content to the right ，大意是界面的左转相当于设备的右转，如果设备向左转时就需要内容（即界面）向右转。即：
UIInterfaceOrientationLandscapeLeft = UIDeviceOrientationLandscapeRight
UIInterfaceOrientationLandscapeRight = UIDeviceOrientationLandscapeLeft
下面还会举例说明。

其实UIDeviceOrientation与UIInterfaceOrientation是两个互不相干的属性，通常情况下会一起出现，在这里正好利用此特性在屏幕旋转后进行重新布局。

4、锁屏

锁屏时，不管系统锁屏是否关闭、Push 或 Present 返回后，界面依然保持不变。

第1步：监听 UIDeviceOrientationDidChangeNotification状态

//监听设备旋转 改变 视图 对应位置
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(deviceOrientationDidChange) name:UIDeviceOrientationDidChangeNotification object:nil];//用来控制横竖屏时调整视图位置
- (void)deviceOrientationDidChange
{[self isPortrait];
}

第2步：重新布局

if (_interOrientation == UIInterfaceOrientationPortrait || _interOrientation == UIInterfaceOrientationPortraitUpsideDown) {self.top.constant = 145;self.bottom.constant = 210;} else if (_interOrientation == UIInterfaceOrientationLandscapeRight || _interOrientation == UIInterfaceOrientationLandscapeLeft) {self.top.constant = 40;self.bottom.constant = 50;}

例如：竖屏转横屏
界面竖屏UIInterfaceOrientationPortrait ->横屏UIInterfaceOrientationLandscapeRight，设备方向UIDeviceOrientationPortrait->UIDeviceOrientationLandscapeLeft,在设备发生变化这个过程触发UIDeviceOrientationDidChangeNotification监听，然后进行重新布局。

3、旋转时状态栏的隐藏与显示

这里只记述旋转时状态栏的变化，由竖屏想横屏变化时状态栏会消失。

//在需要的`UIViewController`设置是否隐藏
- (BOOL)prefersStatusBarHidden {
NSLog(@"%s, line = %d",__FUNCTION__,__LINE__);
return NO;
}

4、锁屏

锁屏时，不管系统锁屏是否关闭、Push 或 Present 返回后，界面依然保持不变。

第1步：设置锁屏

- (IBAction)lockAction:(UIButton *)sender {if (_lockScreen) {_lockScreen = NO;[sender setTitle:@"锁定屏幕" forState:UIControlStateNormal];} else {_lockScreen = YES;[sender setTitle:@"解开屏幕" forState:UIControlStateNormal];}_lockOrientation = _interOrientation;
}

第2步：绕过强转

- (void)interfaceOrientation:(UIInterfaceOrientation)orientation
{[self isPortrait];//锁屏情况下 不旋转if (!_lockScreen) {[self setInterOrientation:orientation];}

第3步：针对 Push 或 Present 返回后

- (void)viewWillAppear:(BOOL)animated {if (_lockScreen) {//记录返回时的界面状态[self setInterOrientation:_lockOrientation];} else {[self isPortrait];}
}

5、针对特定`UIViewController`方向的支持

-(UIInterfaceOrientationMask)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window {if ([NSStringFromClass([[self topViewController] class]) isEqualToString:@"FirstViewController"]) {//横屏return UIInterfaceOrientationMaskLandscapeRight;}//竖屏return UIInterfaceOrientationMaskPortrait;}

最后的献上GitHub代码，还有2个小的 bug ，有兴趣的朋友欢迎来探讨。

- 参考文章：

iOS 屏幕旋转问题总结
iOS 屏幕方向那点事儿