iOS 旋转屏的问题

首先设置旋转屏

基础设置

模态视图方法:

- (BOOL)shouldAutorotate;
- (UIInterfaceOrientationMask)supportedInterfaceOrientations;
- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation;

第一个方法决定是否支持多方向旋转屏，如果返回NO则后面的两个方法都不会再被调用，而且只会支持默认的UIInterfaceOrientationMaskPortrait方向；

第二个方法直接返回支持的旋转方向，该方法在iPad上的默认返回值是UIInterfaceOrientationMaskAll，iPhone上的默认返回值是UIInterfaceOrientationMaskAllButUpsideDown，官方文档有说明

第三个方法返回最优先显示的屏幕方向，比如同时支持Portrait和Landscape方向，但想优先显示Landscape方向，那软件启动的时候就会先显示Landscape，在手机切换旋转方向的时候仍然可以在Portrait和Landscape之间切换

在UINavigationController或者自定义的UINavigationController中重写上面三个方法,即可实现在特定的控制器实现屏幕旋转代码如下:

- (BOOL)shouldAutorotate{
 // 返回当前显示的viewController是否支持旋转
    return [self.visibleViewController shouldAutorotate];
}

- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation{
// 返回当前显示的viewController支持旋转的方向
    return [self.visibleViewController preferredInterfaceOrientationForPresentation];
}

- (UIInterfaceOrientationMask)supportedInterfaceOrientations {
// 返回当前显示的viewController是优先旋转的方向
    if (![self.visibleViewController isKindOfClass:[UIAlertController class]]) {//iOS9 UIWebRotatingAlertController
        return [self.visibleViewController supportedInterfaceOrientations];
    }else{
        return UIInterfaceOrientationMaskPortrait;
    }
}

然后在想要旋转屏幕的的控制器中重写上面三个方法:

- (BOOL)shouldAutorotate {
   return YES;
}

// 这里返回需要支持旋转的方向
- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation{
    return UIInterfaceOrientationLandscapeLeft;
}
// 优先显示的方向
- (UIInterfaceOrientationMask)supportedInterfaceOrientations {
    return UIInterfaceOrientationMaskAll;
}

push控制器方法

//强制转屏
- (void)interfaceOrientation:(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];
    }
}

或者也可以这么做
在AppDelegate中添加方法关闭横竖屏切换,方法如下

1.AppDelegate.h中外露一个属性

@property(nonatomic,assign)BOOL allowRotation;//是否允许转向

2.AppDelegate.m中添加方法(如果属性值为YES,仅允许屏幕向左旋转,否则仅允许竖屏)

- (UIInterfaceOrientationMask)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(nullable UIWindow *)window

{

    if (_allowRotation == YES) {

        return UIInterfaceOrientationMaskLandscapeLeft;

    }else{

        return (UIInterfaceOrientationMaskPortrait);

    }

}

1.在需要强制横屏的控制器.m中添加旋转为横屏方法

- (void)setNewOrientation:(BOOL)fullscreen

{

if (fullscreen) {

        NSNumber *resetOrientationTarget = [NSNumber numberWithInt:UIInterfaceOrientationUnknown];

        [[UIDevice currentDevice] setValue:resetOrientationTarget forKey:@"orientation"];

        

        NSNumber *orientationTarget = [NSNumber numberWithInt:UIInterfaceOrientationLandscapeLeft];

        [[UIDevice currentDevice] setValue:orientationTarget forKey:@"orientation"];

    }else{

        NSNumber *resetOrientationTarget = [NSNumber numberWithInt:UIInterfaceOrientationUnknown];

        [[UIDevice currentDevice] setValue:resetOrientationTarget forKey:@"orientation"];

 

        NSNumber *orientationTarget = [NSNumber numberWithInt:UIInterfaceOrientationPortrait];

        [[UIDevice currentDevice] setValue:orientationTarget forKey:@"orientation"];

    }

}

2.view DidLoad中添加以下代码

AppDelegate * appDelegate = (AppDelegate *)[UIApplication sharedApplication].delegate;

    appDelegate.allowRotation = YES;//(以上2行代码,可以理解为打开横屏开关)

[self setNewOrientation:YES];//调用转屏代码

3.重写导航栏返回箭头按钮,拿到返回按钮点击事件

- (void)back

{

    AppDelegate * appDelegate = (AppDelegate *)[UIApplication sharedApplication].delegate;

    appDelegate.allowRotation = NO;//关闭横屏仅允许竖屏

    [self setNewOrientation:NO];

    [self.navigationController popViewControllerAnimated:YES];

}