iOS屏幕旋转

1. 总开关在工程设置，General-Deployment Info-Device Orientation下勾选工程需要的选项。如果程序中所有的页面不会用到横屏，则只需要勾选Portrait。如果工程中部分页面需要横屏，则需要勾选竖屏和横屏的选项。

2. 在AppDelegate中设置旋转页面：

在AppDelegate.h文件中添加一个Flag，用来设置App全局是否可以横屏。

@property (nonatomic, assign) BOOL isPotrait; //设置整个App是否可以旋转

在AppDelegate.m文件中设置App的旋转代理方法。

#pragma mark-屏幕旋转相关的方法
- (UIInterfaceOrientationMask)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window{
    
    if (self.isPotrait) {
        return UIInterfaceOrientationMaskPortrait;
    }else{
        return UIInterfaceOrientationMaskAllButUpsideDown;
    }
    
}

3. 单个的页面是否可以旋转，需要在代理方法中设置

#pragma mark-支持旋转的代理
- (BOOL)shouldAutorotate{
    return YES;
}

- (UIInterfaceOrientationMask)supportedInterfaceOrientations{
    return UIInterfaceOrientationMaskAllButUpsideDown;
}

4. ViewController嵌套在UINavigationController中，如果ViewController需要横屏展示，此时需要设置UINavigationController的选装代理方法。

 这里提供一个自定义的UINavigationController的实现类：

CustomNavViewController.h

#import <UIKit/UIKit.h>

@interface CustomNavViewController : UINavigationController

@end

CustomNavViewController.m

#import "CustomNavViewController.h"

@interface CustomNavViewController ()

@end

@implementation CustomNavViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.navigationBar.hidden = YES;
    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark-控制页面旋转的方法
- (BOOL)shouldAutorotate{
    return self.topViewController.shouldAutorotate;
}

- (UIInterfaceOrientationMask)supportedInterfaceOrientations{
    return self.topViewController.supportedInterfaceOrientations;
}

@end

5. ViewController嵌套在UITabBarController中，需要设置UITabBarController的旋转方向.

这里提供一个自定义的UITabBarController的类：

CustomTabBarController.h

#import <UIKit/UIKit.h>

@interface CustomTabBarController : UITabBarController

@end

CustomTabBarController.m

#import "CustomTabBarController.h"
#import "CustomNavViewController.h"

@interface CustomTabBarController ()

@end

@implementation CustomTabBarController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark-控制旋转的代理方法
- (BOOL)shouldAutorotate{
    CustomNavViewController *nav = (CustomNavViewController *)[self.viewControllers objectAtIndex:self.selectedIndex];
    return nav.topViewController.shouldAutorotate;
}

- (UIInterfaceOrientationMask)supportedInterfaceOrientations{
    CustomNavViewController *nav = (CustomNavViewController *)[self.viewControllers objectAtIndex:self.selectedIndex];
    return nav.topViewController.supportedInterfaceOrientations;
}

@end