UIKit--UIViewController

UIViewController屏幕旋转

强制旋转为横屏代码：

//这句话是防止手动先把设备置为横屏,导致第二行代码失效.
[[UIDevice currentDevice] setValue:[NSNumber numberWithInteger:UIDeviceOrientationPortrait] forKey:@"orientation"];
[[UIDevice currentDevice] setValue:[NSNumber numberWithInteger:UIDeviceOrientationLandscapeLeft] forKey:@"orientation"];

强制旋转为竖屏代码：

//这句话是防止手动先把设备置为横屏,导致第二行代码失效.
[[UIDevice currentDevice] setValue:[NSNumber numberWithInteger:UIDeviceOrientationLandscapeLeft] forKey:@"orientation"];
[[UIDevice currentDevice] setValue:[NSNumber numberWithInteger:UIDeviceOrientationPortrait] forKey:@"orientation"];

UIViewController支持屏幕旋转需要重写以下两个方法：

// 支持设备自动旋转
- (BOOL)shouldAutorotate{
    return YES;
}
// 支持横竖屏显示
- (NSUInteger)supportedInterfaceOrientations{
    return UIInterfaceOrientationMaskAll;
}

注意:屏幕所支持的方向还要在TARGETS–General–Device Orientation中根据情况勾选(Portrait、UpsideDown、LandscapeLeft、LandscapeRight)。

Device Orientation与supportedInterfaceOrientations方法返回值的对应关系：

Device Orientation	supportedInterfaceOrientations方法返回值
LandscapeLeft	UIInterfaceOrientationMaskLandscapeRight
LandscapeRight	UIInterfaceOrientationMaskLandscapeLeft