我有一个AVCaptureVideoPreviewLayer实例添加到视图控制器视图层次结构.
- (void) loadView {
...
self.previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:nil];
self.previewLayer.frame = self.view.bounds;
self.previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
[self.view.layer addSublayer: _previewLayer];
// adding other UI elements
...
}
...
- (void) _setupPreviewLayerWithSession: (AVCaptureSession*) captureSession
{
self.previewLayer.session = self.captureManager.captureSession;
self.previewLayer.connection.videoOrientation = AVCaptureVideoOrientationLandscapeRight;
}
图层框架在-viewDidLayoutSubviews方法中更新.视图控制器方向锁定到UIInterfaceOrientationMaskLandscapeRight.
问题如下：
>设备以横向方向保持
>视图控制器以模态方式显示 – 视频层正确显示.
>然后锁定设备,当设备锁定时,设备将旋转为纵向.
>然后在仍然处于纵向方向时解锁设备,并且几秒钟后视频层显示为旋转90度.但是,视频层的帧是正确的.所有其他UI元素都正确显示.几秒钟后,图层会捕捉到正确的方向.
请在下面找到图层和UI元素的边界
我尝试将视频图层方向更新为以下(没有结果)：
>订阅AVCaptureSessionDidStartRunningNotification和UIApplicationDidBecomeActiveNotification通知
>调用-viewWillTransitionToSize：withTransitionCoordinator：方法时调用更新
> on -viewWillAppear：
该问题似乎与视频层方向本身无关,而是与查看层次结构布局有关.
更新：
正如所建议的那样,我也尝试更新设备方向更改的视频图层方向,但没有帮助.
我还注意到问题主要发生在应用程序启动后,屏幕首次出现.在同一会话期间的后续屏幕演示中,问题的重现率非常低(例如1/20).
解决方法
试试这段代码：
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(orientationChanged:)
name:UIDeviceOrientationDidChangeNotification
object:nil];
-(void)orientationChanged:(NSNotification *)notif {
[_videoPreviewLayer setFrame:_viewPreview.layer.bounds];
if (_videoPreviewLayer.connection.supportsVideoOrientation) {
_videoPreviewLayer.connection.videoOrientation = [self interfaceOrientationToVideoOrientation:[UIApplication sharedApplication].statusBarOrientation];
}
}
- (AVCaptureVideoOrientation)interfaceOrientationToVideoOrientation:(UIInterfaceOrientation)orientation {
switch (orientation) {
case UIInterfaceOrientationPortrait:
return AVCaptureVideoOrientationPortrait;
case UIInterfaceOrientationPortraitUpsideDown:
return AVCaptureVideoOrientationPortraitUpsideDown;
case UIInterfaceOrientationLandscapeLeft:
return AVCaptureVideoOrientationLandscapeLeft;
case UIInterfaceOrientationLandscapeRight:
return AVCaptureVideoOrientationLandscapeRight;
default:
break;
}
// NSLog(@"Warning - Didn't recognise interface orientation (%d)",orientation);
return AVCaptureVideoOrientationPortrait;
}
