Objective c iOS 8快照尚未渲染的视图将导致空快照
在iOS 8中，我在从相机捕获图像时遇到问题，直到现在我使用此代码Objective c iOS 8快照尚未渲染的视图将导致空快照,objective-c,ios8,uiimagepickercontroller,xcode,Objective C,Ios8,Uiimagepickercontroller,Xcode,在iOS 8中，我在从相机捕获图像时遇到问题，直到现在我使用此代码 UIImagePickerController *controller=[[UIImagePickerController alloc] init]; controller.videoQuality=UIImagePickerControllerQualityTypeMedium; controller.delegate=(id)self; controller.sourceType=UIImagePickerControlle
UIImagePickerController *controller=[[UIImagePickerController alloc] init];
controller.videoQuality=UIImagePickerControllerQualityTypeMedium;
controller.delegate=(id)self;
controller.sourceType=UIImagePickerControllerSourceTypeCamera;
[self presentViewController:controller animated:YES completion:nil];
Snapshotting a view that has not been rendered results in an empty snapshot. Ensure your view has been rendered at least once before snapshotting or snapshot after screen updates.
...
controller.modalPresentationStyle=UIModalPresentationFullScreen;
or
controller.modalPresentationStyle=UIModalPresentationCurrentContext;
...
double delayInSeconds = 0.1;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
[self presentViewController:controller animated:YES completion:nil];
});
[self presentViewController:controller animated:YES completion:NULL];
[self presentViewController:controller animated:YES completion:^{
}];
...
controller.modalPresentationStyle=UIModalPresentationFullScreen;
or
controller.modalPresentationStyle=UIModalPresentationCurrentContext;
...
double delayInSeconds = 0.1;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
[self presentViewController:controller animated:YES completion:nil];
});
[self presentViewController:controller animated:YES completion:NULL];
[self presentViewController:controller animated:YES completion:^{
}];
...
controller.modalPresentationStyle=UIModalPresentationFullScreen;
or
controller.modalPresentationStyle=UIModalPresentationCurrentContext;
...
double delayInSeconds = 0.1;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
[self presentViewController:controller animated:YES completion:nil];
});
[self presentViewController:controller animated:YES completion:NULL];
[self presentViewController:controller animated:YES completion:^{
}];
...
controller.modalPresentationStyle=UIModalPresentationFullScreen;
or
controller.modalPresentationStyle=UIModalPresentationCurrentContext;
...
double delayInSeconds = 0.1;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
[self presentViewController:controller animated:YES completion:nil];
});
[self presentViewController:controller animated:YES completion:NULL];
[self presentViewController:controller animated:YES completion:^{
}];
有什么想法吗？我很确定这只是iOS 8.0中的一个bug。它可以通过最简单的POC应用程序复制，这些应用程序只不过是像上面那样尝试呈现一个
UIImagePickerController也就是说，这个功能对我来说仍然有效。除了警告/错误之外，您的应用程序的功能是否存在问题？我一直在努力解决这个问题，几个小时以来，我阅读了所有相关主题，发现错误是因为在我设备的隐私设置下，摄像头对我的应用程序的访问被阻止！！！我从来没有拒绝过使用摄像头，我不知道它是如何被阻止的，但这就是问题所在 我也遇到了同样的问题，我通过检查摄像头是否可用来解决它：
BOOL cameraAvailableFlag = [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];
if (cameraAvailableFlag)
[self performSelector:@selector(showcamera) withObject:nil afterDelay:0.3];
我发现了同样的问题并尝试了一切。我有两个不同的应用程序，一个在objective-C中，一个在swift中，它们都有相同的问题。错误消息出现在调试器中，第一张照片后屏幕变黑。这只发生在iOS>=8.0中，显然这是一个bug 我找到了一个困难的解决办法。使用imagePicker.showsCameraControls=false关闭相机控件，并创建自己的覆盖视图，其中包含缺少的按钮。关于如何做到这一点，有各种各样的教程。
奇怪的错误消息仍然存在，但至少屏幕没有变黑，并且您有一个正常工作的应用程序。我在调用UIImagePickerController presentViewController:从回调到UIAlertView委托后遇到了这个问题。我通过推动presentViewController解决了这个问题：使用dispatch\u async取消当前执行跟踪
- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
{
dispatch_async(dispatch_get_main_queue(), ^{
UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
imagePickerController.delegate = self;
if (buttonIndex == 1)
imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
else
imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
[self presentViewController: imagePickerController
animated: YES
completion: nil];
});
}
我在设置一些视图的动画时遇到了这个问题，应用程序将进入背景模式并返回。我通过设置一个标志isActive来处理它。我把它设为“否”
- (void)applicationWillResignActive:(UIApplication *)application
- (void)applicationDidBecomeActive:(UIApplication *)application
并相应地设置或不设置视图的动画。已解决此问题。这可能是内置ImagePickerController的一个错误。我的代码正常工作，但在iPhone6Plus上偶尔会崩溃
UIImagePickerControllerSourceType source = [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera] ? UIImagePickerControllerSourceTypeCamera : UIImagePickerControllerSourceTypeSavedPhotosAlbum;
UIImagePickerController *cameraController = [[UIImagePickerController alloc] init];
cameraController.delegate = self;
cameraController.sourceType = source;
cameraController.allowsEditing = YES;
[self presentViewController:cameraController animated:YES completion:^{
//iOS 8 bug. the status bar will sometimes not be hidden after the camera is displayed, which causes the preview after an image is captured to be black
if (source == UIImagePickerControllerSourceTypeCamera) {
[[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation:UIStatusBarAnimationNone];
}
}];
我尝试过其他答案所建议的所有解决方案，但都没有成功。切换到后问题终于解决。我遇到了这个问题。当我们调用相机并释放此问题产生的视图时。例如，在ViewDidDemouse方法中调用camera并设置view nil，由于camera事件没有回调，因此会出现此错误。对于此错误，也请确保此情况。对于在图像捕获后看到黑色预览问题的任何人，在显示UIPickerController后隐藏状态栏似乎可以解决此问题
UIImagePickerControllerSourceType source = [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera] ? UIImagePickerControllerSourceTypeCamera : UIImagePickerControllerSourceTypeSavedPhotosAlbum;
UIImagePickerController *cameraController = [[UIImagePickerController alloc] init];
cameraController.delegate = self;
cameraController.sourceType = source;
cameraController.allowsEditing = YES;
[self presentViewController:cameraController animated:YES completion:^{
//iOS 8 bug. the status bar will sometimes not be hidden after the camera is displayed, which causes the preview after an image is captured to be black
if (source == UIImagePickerControllerSourceTypeCamera) {
[[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation:UIStatusBarAnimationNone];
}
}];
我没有足够的声誉点数来评论@greg的上述回答，因此我将在这里添加我的观察结果。我有一个针对iPad和iPhone的Swift项目。我的主视图控制器中有一个方法（下面的相关部分）。当我在手机上测试时，一切正常，不会产生任何警告。当我在iPad上运行它时，一切正常，但我看到了关于快照视图的警告。然而，有趣的是，当我在没有使用popover控制器的情况下在iPad上运行时，一切正常，没有任何警告。不幸的是，苹果公司规定，如果不使用相机，图像采集器必须在iPad上的popover中使用
dispatch_async(dispatch_get_main_queue(), {
let imagePicker: UIImagePickerController = UIImagePickerController();
imagePicker.sourceType = UIImagePickerControllerSourceType.SavedPhotosAlbum;
imagePicker.mediaTypes = [kUTTypeImage];
imagePicker.allowsEditing = false;
imagePicker.delegate = self;
if(UIDevice.currentDevice().userInterfaceIdiom == .Pad){ // on a tablet, the image picker is supposed to be in a popover
let popRect: CGRect = buttonRect;
let popover: UIPopoverController = UIPopoverController(contentViewController: imagePicker);
popover.presentPopoverFromRect(popRect, inView: self.view, permittedArrowDirections: UIPopoverArrowDirection.Up, animated: true);
}else{
self.presentViewController(imagePicker, animated: true, completion: nil);
}
});
我什么都试过了，我的问题是相机和照片库的图像采集器在它们出现后立即消失了。我用下面这句话解决了它（swift）
我也有同样的错误，在打开相机的时候在控制台里收到了下面的信息 '对尚未渲染的视图进行快照将导致空快照。确保您的视图在快照之前或屏幕更新之后至少呈现一次。” 对我来说，问题在于Info.plist文件中的捆绑显示名称。它是空的。我如何将我的应用程序名称放在那里，现在它工作正常。由于捆绑显示名称为空，我没有收到任何相机权限警报。它阻止了视图的渲染
问题不在视图中，而是在未经许可的情况下显示。如果您的应用未列出，则可以在设置-->隐私-->摄像头上检查该问题。问题可能与此相同 我使用的是Phonegap，但在谷歌搜索错误消息时，此线程始终作为第一个线程出现 对我来说，通过将imagetype定义为PNG，解决了这个问题
encodingType : Camera.EncodingType.PNG
navigator.camera.getPicture(successFunction, failFunction, { encodingType : Camera.EncodingType.PNG, correctOrientation:true, sourceType : Camera.PictureSourceType .PHOTOLIBRARY, quality: 70, allowEdit : false , destinationType: Camera.DestinationType.DATA_URL});
您的里程数可能会有所不同，但这对我来说很有用。调用此方法对我很有效。在呈现您的视图后放置它
[yourViewBeingPresented.view layoutIfNeeded];
我有一个UIAlertControllerStyleActionSheet，让用户可以选择用相机拍照或使用图书馆的照片 我在错误消息上尝试了一个符号断点 这向我表明，错误是在演示过程中实习生使用UICollectionView产生的
[self presentViewController:alert animated:YES completion:nil];
[alert setPreferredContentSize: alert.view.frame.size];
-(void)showImageSourceAlertFromSender:(id)sender{
UIButton *senderButton = (UIButton*)sender;
UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
UIAlertAction *cameraAction = [UIAlertAction actionWithTitle:@"Camera" style:UIAlertActionStyleDefault
handler:^(UIAlertAction *action) {
[self takePhoto];
}];
UIAlertAction *libraryAction = [UIAlertAction actionWithTitle:@"Library" style:UIAlertActionStyleDefault
handler:^(UIAlertAction *action) {
[self selectPhotoFromLibraryFromSender:sender];
}];
[alert addAction:cameraAction];
[alert addAction:libraryAction];
alert.popoverPresentationController.delegate = self;
alert.popoverPresentationController.sourceRect = senderButton.frame;
alert.popoverPresentationController.sourceView = self.view;
[alert setPreferredContentSize: alert.view.frame.size];
[self presentViewController:alert animated:YES completion:^(){
}];}
viewUIAlertController *controller = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
controller.modalPresentationStyle = UIModalPresentationPopover;
controller.popoverPresentationController.barButtonItem = (UIBarButtonItem *)sender;
... setup the UIAlertController ...
[controller view]; // <--- Add to silence the warning.
[self presentViewController:controller animated:YES completion:nil];
UIAlertController*控制器=[UIAlertController alertControllerWithTitle:nil消息：nil首选样式：UIAlertControllerStyleActionSheet]；
controller.modalPresentationStyle=UIModalPresentati