iOS 8 强制横屏

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation{
    return (interfaceOrientation == UIInterfaceOrientationLandscapeLeft || interfaceOrientation == UIInterfaceOrientationLandscapeRight );
}

- (BOOL)shouldAutorotate{
    return YES;
}

- (NSUInteger)supportedInterfaceOrientations{
    return UIInterfaceOrientationMaskAll;
}

//强制切换
- (void)switchToLandspance{
    [[UIDevice currentDevice] setValue:[NSNumber numberWithInteger:UIDeviceOrientationPortrait] forKey:@"orientation"];//这句话是防止手动先把设备置为横屏,导致下面的语句失效.
    [[UIDevice currentDevice] setValue:[NSNumber numberWithInteger:UIDeviceOrientationLandscapeLeft] forKey:@"orientation"];
}