iOS App大多数情况下都是只支持竖屏的，少部分页面才支持旋转，甚至有些页面需要强制横屏。本文将介绍应用如何支持旋转，以及旋转后我们页面需要如何处理的。
UIDeviceOrientation和UIInterfaceOrientation
iOS旋转包括设备旋转和界面旋转，设备方向我们控制不了，看用户怎么握住他的手机，界面方向一般跟着设备方向旋转而旋转（如果支持的话），通常我们说的APP支持旋转，就是界面旋转。
屏幕快照 2018-07-02 上午9.56.41.png
UIDeviceOrientation：设备方向
iOS设备方向是通过加速计来获取的，总共有七个方向：
typedef NS_ENUM(NSInteger, UIDeviceOrientation) {
UIDeviceOrientationUnknown,
UIDeviceOrientationPortrait, // Device oriented vertically, home button on the bottom
UIDeviceOrientationPortraitUpsideDown, // Device oriented vertically, home button on the top
UIDeviceOrientationLandscapeLeft, // Device oriented horizontally, home button on the right
UIDeviceOrientationLandscapeRight, // Device oriented horizontally, home button on the left
UIDeviceOrientationFaceUp, // Device oriented flat, face up
UIDeviceOrientationFaceDown // Device oriented flat, face down
} __TVOS_PROHIBITED;
当设备方向变化时候，会发出通知UIDeviceOrientationDidChangeNotification，注册监听该通知来处理页面。
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
//开启和监听 设备旋转的通知（不开启的话，设备方向一直是UIInterfaceOrientationUnknown）
if (![UIDevice currentDevice].generatesDeviceOrientationNotifications) {
[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
}
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleDeviceOrientationChange:) name: UIDeviceOrientationDidChangeNotification object:nil];
}
//设备方向改变的处理
- (void)handleDeviceOrientationChange:(NSNotification *)notification{
UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;
switch (ddeviceOrientation) {
case UIDeviceOrientationFaceUp:
NSLog(@"屏幕朝上平躺");
break;
case UIDeviceOrientationFaceDown:
NSLog(@"屏幕朝下平躺");
break;
case UIDeviceOrientationUnknown:
NSLog(@"未知方向");
break;
case UIDeviceOrientationLandscapeLeft:
NSLog(@"屏幕向左横置");
break;
case UIDeviceOrientationLandscapeRight:
NSLog(@"屏幕向右橫置");
break;
case UIDeviceOrientationPortrait:
NSLog(@"屏幕直立");
break;
case UIDeviceOrientationPortraitUpsideDown:
NSLog(@"屏幕直立，上下顛倒");
break;
default:
NSLog(@"无法辨识");
break;
}
}
//最后在dealloc中移除通知，并结束设备旋转的通知
- (void)dealloc {
[[NSNotificationCenter defaultCenter] removeObserver:self];
[[UIDevice currentDevice] endGeneratingDeviceOrientationNotifications];
}
UIInterfaceOrientation：界面方向
iOS界面方向和Home的按钮方向是一致的，总共有五个方向：
typedef NS_ENUM(NSInteger, UIInterfaceOrientation) {
UIInterfaceOrientationUnknown = UIDeviceOrientationUnknown,
UIInterfaceOrientationPortrait = UIDeviceOrientationPortrait,
UIInterfaceOrientationPortraitUpsideDown = UIDeviceOrientationPortraitUpsideDown,
UIInterfaceOrientationLandscapeLeft = UIDeviceOrientationLandscapeRight,
UIInterfaceOrientationLandscapeRight = UIDeviceOrientationLandscapeLeft
} __TVOS_PROHIBITED;
当界面方向变化时候，会发出通知UIApplicationWillChangeStatusBarOrientationNotification、UIApplicationDidChangeStatusBarOrientationNotification，注册监听该通知来处理页面。
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleStatusBarOrientationChange:) name: UIApplicationDidChangeStatusBarOrientationNotification object:nil];
}
//界面方向改变的处理
- (void) handleStatusBarOrientationChange:(NSNotification *)notification{
UIInterfaceOrientation interfaceOrientation = [[UIApplication sharedApplication] statusBarOrientation];
switch (interfaceOrientation) {
case UIInterfaceOrientationUnknown:
NSLog(@"未知方向");
break;
case UIInterfaceOrientationPortrait:
NSLog(@"界面直立");
break;
case UIInterfaceOrientationPortraitUpsideDown:
NSLog(@"界面直立，上下颠倒");
break;
case UIInterfaceOrientationLandscapeLeft:
NSLog(@"界面朝左");
break;
case UIInterfaceOrientationLandscapeRight:
NSLog(@"界面朝右");
break;
default:
break;
}
}
//最后在dealloc中移除通知
- (void)dealloc {
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
视图控制器中旋转方向的设置
支持旋转（不建议）：
在项目的General-->Deployment Info-->Device Orientation中，勾选支持的方向，一般Upside Down不勾选，没几个APP会支持颠倒。
屏幕快照 2018-07-02 上午9.43.32.png
备注：为什么不建议呢？因为这样设置的话，如果你的启动页使用的是LaunchScreen.storyboard，那么当你横屏启动APP时，启动页也会横屏启动，而不是竖屏启动，这很怪异（一般app启动页面都是竖屏的）；然而，貌似使用LaunchImage设置启动页，有不受影响，当你横屏启动APP时，启动页依然是竖屏，有点没搞懂。
在AppDelegate中实现代理：（建议）
- (UIInterfaceOrientationMask)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window {
return UIInterfaceOrientationMaskPortrait | UIInterfaceOrientationMaskLandscape;
}
备注：注意，如果APP有多个window，判断下window回更合理些，这里返回的是keyWindow；当然，你所有window都支持该旋转方向，也不是不可以。
支持ViewController屏幕方向设置
我们需要通过重载ViewController方法，来控制界面是否支持旋转，以及旋转方向。
WDMainTabBarController
#pragma mark - Orientation
- (BOOL)shouldAutorotate {
return [self.selectedViewController shouldAutorotate];
}
- (UIInterfaceOrientationMask)supportedInterfaceOrientations{
return [self.selectedViewController supportedInterfaceOrientations];
}
WDBaseNavigationController
#pragma mark - Orientation
- (BOOL)shouldAutorotate {
return [[self.viewControllers lastObject] shouldAutorotate];
}
- (UIInterfaceOrientationMask)supportedInterfaceOrientations {
return [[self.viewControllers lastObject] supportedInterfaceOrientations];
}
WDBaseViewController
由于APP默认仅支持竖屏，所有我写了个基类BaseViewController，在基类中实现如下方法：
#pragma mark - Orientation
- (BOOL)shouldAutorotate {
return NO;
}
- (UIInterfaceOrientationMask)supportedInterfaceOrientations {
return UIInterfaceOrientationMaskPortrait;
}
WDWebViewController
WDWebViewController支持制动旋转
#pragma mark - Orientation
- (BOOL)shouldAutorotate {
return YES;
}
- (UIInterfaceOrientationMask)supportedInterfaceOrientations {
return UIInterfaceOrientationMaskAll;
}
WDThirdViewController
WDThirdViewController强制横屏
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
self.navigationItem.title = @"Third";
self.oldOrientation = [UIDevice currentDevice].orientation;
if (self.oldOrientation == UIDeviceOrientationLandscapeLeft) {
// 如果设备本身是横屏的，但界面不是横屏，这时候直接设置LandscapeLeft不生效，需要设置Unknown欺骗系统后，再设置横屏
[[UIDevice currentDevice] setValue:[NSNumber numberWithInteger:UIDeviceOrientationUnknown] forKey:@"orientation"];
}
}
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
UIInterfaceOrientation interfaceOrientation = [[UIApplication sharedApplication] statusBarOrientation];
switch (interfaceOrientation) {
case UIInterfaceOrientationLandscapeLeft:
case UIInterfaceOrientationLandscapeRight: {
// 本身是横屏，直接break
break;
}
default: {
// 强制横屏
[[UIDevice currentDevice] setValue:[NSNumber numberWithInteger:UIDeviceOrientationLandscapeLeft] forKey:@"orientation"];
break;
}
}
}
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
// 还原设备方向
[[UIDevice currentDevice] setValue:[NSNumber numberWithInteger:self.oldOrientation] forKey:@"orientation"];
}
#pragma mark - Orientation
- (BOOL)shouldAutorotate {
return YES;
}
- (UIInterfaceOrientationMask)supportedInterfaceOrientations {
return UIInterfaceOrientationMaskLandscape;
}
至于旋转页面的处理，我在WDBaseViewController中添加了通知和方法：
//监听UIApplicationDidChangeStatusBarOrientationNotification的处理
- (void)handleStatusBarOrientationChange: (NSNotification *)notification {
UIInterfaceOrientation interfaceOrientation = [[UIApplication sharedApplication] statusBarOrientation];
BOOL isLandscape = NO;
switch (interfaceOrientation) {
case UIInterfaceOrientationUnknown: {
//NSLog(@"未知方向");
break;
}
case UIInterfaceOrientationPortrait:
case UIInterfaceOrientationPortraitUpsideDown: {
isLandscape = NO;
break;
}
case UIInterfaceOrientationLandscapeLeft:
case UIInterfaceOrientationLandscapeRight: {
isLandscape = YES;
break;
}
default:
break;
}
CGFloat navBarHeight = WD_NAV_BAR_HEIGHT;
if (isLandscape) {
navBarHeight = WD_NAV_BAR_HEIGHT_LANDSCAPE;
}
[self updateLayoutNavBarWhenAutorotate:navBarHeight isLandscape:isLandscape];
}
- (void)updateLayoutNavBarWhenAutorotate:(CGFloat)navBarHeight isLandscape:(BOOL)isLandscape {
self.navigationBarBackImageView.frame = CGRectMake(0, 0, WD_SCREEN_WIDTH, navBarHeight);
self.navigationBarLineView.frame = CGRectMake(0, navBarHeight - 0.5, WD_SCREEN_WIDTH, 0.5);
}
子类WDBaseWebViewController重载
- (void)updateLayoutNavBarWhenAutorotate:(CGFloat)navBarHeight isLandscape:(BOOL)isLandscape {
[super updateLayoutNavBarWhenAutorotate:navBarHeight isLandscape:isLandscape];
CGRect frame =CGRectMake(0, navBarHeight, WD_SCREEN_WIDTH, WD_SCREEN_HEIGHT - navBarHeight);
self.webView.frame = frame;
}
最后
这里有几个地方需要注意的，竖屏和横屏之后的navigationBar和tabBar的宽高都发生了变化，而且不同设备之间大小有差异，比如：
- iphone 7竖屏时，navigationBar的宽高是(375, 44)，statusBar的宽高是(375, 20)，横屏时，navigationBar宽高是(667, 32)，statusBar的宽高是(667, 0)
- iphone x竖屏时，navigationBar的宽高是(375, 44)，statusBar的宽高是(375, 44)，横屏时，navigationBar宽高是(812, 32)，statusBar的宽高是(812, 0)
还有一个有意思的是：当你横屏的时候，状态栏会被隐藏不见了（可能是横屏为了更多的展示内容），如果我们需要将状态栏显示出来，ViewController需要重载prefersStatusBarHidden方法，因此我在WDBaseViewController中添加如下方法：
#pragma mark - Status Bar
- (BOOL)prefersStatusBarHidden {
return NO;
}
在WDBaseNavigationController中添加如下方法：
#pragma mark - Status Bar
- (UIViewController *)childViewControllerForStatusBarHidden {
return self.topViewController;
}
- (UIStatusBarStyle)preferredStatusBarStyle {
return UIStatusBarStyleLightContent;
}
but 在iphone x中，无论我如何尝试，状态栏都不会出现，始终隐藏，不得其解。
备注：通过
CGRectGetWidth([UIScreen mainScreen].bounds)，获取的宽高都是旋转后的值。
Demo地址