sadly i had to migrate from UIActionSheet to UIAlertController because IOS8 removed the first's functionality.
before using that, every time i went to and from home screen, the parent's view "viewDidDisappear" was called so i could dismiss the menu i've created.
now it's not called anymore.
the code looks like:
UIAlertController *alert = [UIAlertController .... preferredStyle:UIAlertControllerSTyleActionSheet]
UIAlertAction* a = [....]
[alert addAction: a];
alert.popoverPresentationController.barButtonItem = self.myButton // the bar button from my view
[self presentViewController:alert animated:YES completion:nil] // maybe im not showing the view well?
i have no idea how to continue from here.. would love some help
Thanks.
== EDIT ==
i saw that it happens also with the deprecated UIActionSheet and also with UIDcoumentInteractionController - ONLY in IOS8, not in IO7
Maybe I'm thinking too simple here, but wouldn't it be the easiest to put whatever code you had in a separate method and call that method from viewDidDisappear and after that bit of code you use to present that alert controller?
- (void)viewDidDisappear {
[self hideMenu];
}
- (void)hideMenu {
// Do all stuff to hide the menu you previously did in viewDidDisappear
}
And alter that presenting code like this
// more code here
[self presentViewController:alert animated:YES completion:nil];
[self hideMenu];
In iOS 8 I am having problem capturing images from camera till now I am using this code for
UIImagePickerController *controller=[[UIImagePickerController alloc] init];
controller.videoQuality=UIImagePickerControllerQualityTypeMedium;
controller.delegate=(id)self;
controller.sourceType=UIImagePickerControllerSourceTypeCamera;
[self presentViewController:controller animated:YES completion:nil];
But in iOS 8 I am getting this:
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.
I have tried with the solution provided by This Post with
#property (strong,nonatomic)UIImagePickerController *controller;
_controller=[[UIImagePickerController alloc] init];
_controller.videoQuality=UIImagePickerControllerQualityTypeMedium;
_controller.delegate=(id)self;
_controller.sourceType=UIImagePickerControllerSourceTypeCamera;
_[self presentViewController:controller animated:YES completion:nil];
and this
...
controller.modalPresentationStyle=UIModalPresentationFullScreen;
or
controller.modalPresentationStyle=UIModalPresentationCurrentContext;
...
and this
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];
});
and this
[self presentViewController:controller animated:YES completion:NULL];
and this
[self presentViewController:controller animated:YES completion:^{
}];
any idea?
I'm pretty sure this is just a bug in iOS 8.0. It's reproducible with the simplest of POC apps that does nothing more than attempt to present a UIImagePickerController like you're doing above. Furthermore, there's no alternative pattern to displaying the image picker/camera, to my knowledge. You can even download Apple's Using UIImagePickerController sample app, run it, and it will generate the same error out of the box.
That said, the functionality still works for me. Other than the warning/error, do you have issues with the functioning of your app?
I was struggling with this issue for several hours, i have read every relevant topic and found out that the error was caused because under the privacy settings of my device, the camera access to my app was blocked!!! I have never denied access to camera and i don't know how it was blocked but that was the problem!
I don't have enough reputation points to comment on #greg's answer above, so will add my observations here. I have a Swift project for both iPad and iPhone. I have a method inside my main view controller (relevant bit below). When I test this on a phone, everything works properly and no warnings are generated. When I run it on an iPad, everything works properly but I see the warning about snapshotting the view. The interesting bit, however, is that when I run on an iPad without using the popover controller, everything works properly with no warning. Unfortunately, Apple mandates that the image picker must be used within a popover on iPad, if the camera is not being used.
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);
}
});
I ran into this after calling UIImagePickerController presentViewController: from the callback to a UIAlertView delegate. I solved the issue by pushing the presentViewController: call off the current execution trace using dispatch_async.
- (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];
});
}
I had this issue when animating some views and the app would go into background mode and come back. I handled it by setting a flag isActive. I set it to NO in
- (void)applicationWillResignActive:(UIApplication *)application
and YES in
- (void)applicationDidBecomeActive:(UIApplication *)application
and animate or not animate my views accordingly. Took care of the issue.
I had this with an UIAlertControllerStyleActionSheet giving the user the option to take a photo with the camera or use one from library.
I tried a symbolic breakpoint on the error message
That showed me the error is produced by the intern use of a UICollectionView during presentation
[self presentViewController:alert animated:YES completion:nil];
I fixed this by explixitly setting the frame before presenting
[alert setPreferredContentSize: alert.view.frame.size];
Here is the complete methode that is working without the error
-(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:^(){
}];}
You can silence the "Snapshotting a view" warning by referencing the view property before presenting the view controller. Doing so causes the view to load and allows iOS render it before taking the snapshot.
UIAlertController *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];
For anyone that is seeing an issue with a black preview after image capture, hiding the status bar after the UIPickerController is shown seems to fix the issue.
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];
}
}];
I found the same issue and tried everything. I have two different apps, one in objective-C and one in swift - both have the same problem. The error message comes in the debugger and the screen goes black after the first photo. This only happens in iOS >= 8.0, obviously it is a bug.
I found a difficult workaround. Shut off the camera controls with imagePicker.showsCameraControls = false and create your own overlayView that has the missing buttons. There are various tutorials around how to do this.
The strange error message stays, but at least the screen doesn't go black and you have a working app.
This might be a bug of built-in ImagePickerController. My code is working, but occasionally crashes on iPhone 6 Plus.
I've tried all solutions suggested by other answers but there were no luck. Problem finally solved after switching to JPSImagePickerController.
I've tried everything, my problem was that the image picker for the camera and photo library disappeared right after they showed. I solved it with the following line (swift)
imagePicker.modalPresentationStyle = UIModalPresentationStyle.OverCurrentContext
I'm pretty sure this is just a bug in iOS 8.0. It's reproducible with the simplest of POC apps that does nothing more than attempt to present a UIImagePickerController like you're doing above. Furthermore, there's no alternative pattern to displaying the image picker/camera, to my knowledge. You can even download Apple's Using UIImagePickerController sample app, run it, and it will generate the same error out of the box.
That said, the functionality still works for me. Other than the warning/error, do you have issues with the functioning of your app?
If we are using the UIImagePickerController as a property, then this warning will disappear. xcode assume that we are not using the result from the UIImagePickerController , if we are instantiating the UIImagePickerController within a function.
Calling this method worked for me. Place it after presenting your view.
[yourViewBeingPresented.view layoutIfNeeded];
I also encounter the same problem and I resolved it by checking if the camera is available:
BOOL cameraAvailableFlag = [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];
if (cameraAvailableFlag)
[self performSelector:#selector(showcamera) withObject:nil afterDelay:0.3];
I have came across with this issue. When we call the camera and release the views produced this issue. For an example call an camera and set view nil in viewDidDisappear method this error will come since there is not callback for camera event. Make sure about this case too for this error.
I got the same bug,getting bellow message in console while opening camera.
'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.'
For me problem was with the Bundle display name in Info.plist file.it was empty some how,i put my app name there and now it working fine.i did't received any camera permission alert because of empty Bundle display name.it blocked the view from rendering.
the problem was't with view but by presenting it without a permission.you can check it on settings-->privacy-->Camera,if your app not listed there problem might be same.
I'm using Phonegap, but this thread keeps coming as the first one when Googling about the error message.
For me this issue went away by defining the imagetype to PNG.
encodingType : Camera.EncodingType.PNG
So the whole line being:
navigator.camera.getPicture(successFunction, failFunction, { encodingType : Camera.EncodingType.PNG, correctOrientation:true, sourceType : Camera.PictureSourceType .PHOTOLIBRARY, quality: 70, allowEdit : false , destinationType: Camera.DestinationType.DATA_URL});
Your mileage may vary, but that did the trick for me.
Alternatively, consider using drawViewHierarchyInRect:
Swift:
extension UIImage{
class func renderUIViewToImage(viewToBeRendered: UIView) -> UIImage
{
UIGraphicsBeginImageContextWithOptions(viewToBeRendered.bounds.size, true, 0.0)
viewToBeRendered.drawViewHierarchyInRect(viewToBeRendered.bounds, afterScreenUpdates: true)
viewToBeRendered.layer.renderInContext(UIGraphicsGetCurrentContext()!)
let finalImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return finalImage
}
}
Objective-C:
- (UIImage *)snapshot:(UIView *)view
{
UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, 0);
[view drawViewHierarchyInRect:view.bounds afterScreenUpdates:YES];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
Also see:
https://developer.apple.com/library/ios/qa/qa1817/_index.html
How to capture UIView to UIImage without loss of quality on retina display
In my case ( XCode 7 and iOS 9 ), I use UINavigationController "hidden", so Ihave to add UINavigationControllerDelegate to present camera or roll and it work like it is supposed to! And pickerControllerDelegate.self doesn't display error either!
I've got a login screen I want to hide like:
[self dismissModalViewControllerAnimated:true];
But the problem is that I need to display it like this:
-(void)viewDidAppear:(BOOL)animated {
[self presentModalViewController:loginScreen animated:false];
}
Which means I'll flash the current screen before I popup the login screen.
So what I'm looking for is a way to show the login screen instantly and transition to the main screen with the same animation as dissmissModalViewControllerAnimated:true.
You should be able to just disable the animation so its instant?
[self presentModalViewController:loginScreen animated:NO];
Do it in viewWillAppear if it still flashes briefly.
What I've done (maybe not the best solution):
- (void)viewDidLoad
{
// Initial set to hidden for avoiding a flickering UI
self.view.hidden=YES;
}
-(void)viewWillAppear:(BOOL)animated
{
[NSTimer scheduledTimerWithTimeInterval:0 block:^{
[self presentModalViewController:self.loginViewController animated:NO];
} repeats:false];
}
And just before you dispatch the ModalViewController you set self.view.hidden=NO.
See https://github.com/jivadevoe/NSTimer-Blocks for the NSTimer using blocks
I am using a UIActivityIndicatorView as an IBOutlet. I am trying to control it using [activityView startAnimating] and [activityView stopAnimating].
I have enabled 'Hides when stopped' and 'Animating' behaviors in XIB file.
I want to start animate the spinner for several user actions inside the controller. But after the first [activityView stopAnimating] call it does not response to [activityView startAnimating] call again.
That is mean the spinner is disappeared after the first [activityView stopAnimating] call.
I tried activeView.hidden = NO; before the next [activityView startAnimating] call. But it does not work.
Any idea about this issue?
Edited
After my controller loaded I do follow thing,
do {
[self.activityIndicator startAnimating];
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
[webServiceCallOperation getResults];
[self.activityIndicator stopAnimating];
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
} while (![webServiceCallOperation isValideResponse] || [webServiceCallOperation isServerError]);
In the same controller I have a IBAction for a button click.
- (IBAction)tappedSearchButton:(id)sender
{
[self.activityIndicator startAnimating];
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
[self tappedSearchButtonAction];
[self.activityIndicator stopAnimating];
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
}
I noticed that the spinner not begin to animate just after the [self.activityIndicator startAnimating]; call. Using [self tappedSearchButtonAction]; I call to a web service and go to the search results view. The spinner begin to animate just before change the view. That's why I did not see it. But I suppose to animate it before web service call and should animate it while my web service call.
Same behavior of the network activity indicator.
As aadhira suggested check for release and if you are making the calls on the main thread.
[NSObject performSelectorOnMainThread:#selector(SEL) withObject:nil waitUntilDone:YES];
It starts animating because as you say you have enabled Animating behavior in the XIB file. But after you stop it for the first time, it is not animating anymore until you start it again programatically.
when i click on button which title is click here to enlarge then i want show activity indicator on the first view and remove when load this view.
but i go back then it show activity indicator which is shown in this view.
in first vie .m file i have use this code for action.
-(IBAction)btnSelected:(id)sender{
UIButton *button = (UIButton *)sender;
int whichButton = button.tag;
NSLog(#"Current TAG: %i", whichButton);
UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
[spinner setCenter:CGPointMake(160,124)];
[self.view addSubview:spinner];
[spinner startAnimating];
if(whichButton==1)
{
[spinner stopAnimating];
first=[[FirstImage alloc]init];
[self.navigationController pushViewController:first animated:YES];
[spinner hidesWhenStopped ];
}}
in above code i have button action in which i call next view. Now i want show/display activity indicator when view upload. In next view i have a image view in which a image i upload i have declare an activity indicator which also not working. How do that?
Toro's suggestion offers a great explanation and solution, but I just wanted to offer up another way of achieving this, as this is how I do it.
As Toro said,
- (void) someFunction
{
[activityIndicator startAnimation];
// do computations ....
[activityIndicator stopAnimation];
}
The above code will not work because you do not give the UI time to update when you include the activityIndicator in your currently running function. So what I and many others do is break it up into a separate thread like so:
- (void) yourMainFunction {
activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
[NSThread detachNewThreadSelector:#selector(threadStartAnimating) toTarget:self withObject:nil];
//Your computations
[activityIndicator stopAnimating];
}
- (void) threadStartAnimating {
[activityIndicator startAnimating];
}
Good luck!
-Karoly
[self.navigationController pushViewController:first animated:YES];
Generally, when you push a view controller into navigation controller, it will invoke the -(void)viewWillAppear: and -(void)viewDidAppear: methods. You can add activity indicator view inside the viewWillAppear: and call startAnimation of indicator view. You CANNOT invoke startAnimation and stopAnimation at the same time. For example,
- (void)viewWillAppear:(BOOL)animated
{
[aIndicatorView startAnimation];
// do somethings ....
[aIndicatorView stopAnimation];
}
Because the startAnimation and stopAnimation are under the same time, then no animation will show.
But if you invoke startAnimation in -(void)viewWillAppear: and invoke stopAnimation in another message, like followings.
- (void)viewWillAppear:(BOOL)animated
{
[aIndicatorView startAnimation];
// do somethings...
}
- (void)viewDidAppear:(BOOL)animated
{
[aIndicatorView stopAnimation];
}
Because viewWillAppear: and viewDidAppear: are invoked with different event time, the activity indicator view will work well.
Or, you can do something like followings:
- (void)viewWillAppear:(BOOL)animated
{
[aIndicatorView startAnimation];
// Let run loop has chances to animations, others events in run loop queue, and ... etc.
[[NSRunLoop currentRunLoop] runUntilDate:[NSDate date]];
// do somethings ....
[aIndicatorView stopAnimation];
}
The above example is a bad example, because it invokes two or more animations in the -runUntilDate:. But it will let the activity indicator view work.
Create a webview. Add a activity indicator to the webview. If you are loading a image via url into the webview then implement the webview delegate methods. Once the url is loaded then stopanimating the activity indicator.
Let me know which step you are not able to implement.