UIImagePickerController works in iOS 11.1 but not in iOS 11.4

Question

I have a fairly typical set of controls to take a picture or choose from a user's photo library. The latest OS version I have in Xcode is 11.1, and the image picker works with the code I have. (I don't know whether it's possible to run a newer version on the simulator yet.)

When I run the code on an actual iPhone (5s with iOS 11.4), I get a discovery error from the image picker:

Error Domain=PlugInKit Code=13 "query cancelled" UserInfo={NSLocalizedDescription=query cancelled}

Trying to use the camera simply results in returning to the view controller, apparently with no action taken on the new image data, and no error messages.

EDIT: I have camera and photo library permissions to the info.plist, but they don't seem to affect this issue.

Here's the relevant code (the VC does several other unrelated things):

UserProfileViewController.h

#import <UIKit/UIKit.h>

@interface UserProfileViewController : UIViewController <NSURLSessionDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate, UIScrollViewDelegate>
{
    __weak IBOutlet UIScrollView *scrolview;

}

@end

UserProfileViewController.m:

#import "UserProfileViewController.h"

. . . 

- (IBAction)takePhoto:(id)sender {

if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {

    UIAlertController *errAlertController = [UIAlertController alertControllerWithTitle:@"Whoa!" message:@"This phone doesn't have a camera." preferredStyle:UIAlertControllerStyleAlert];
    [errAlertController addAction:[UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:nil]];
    [self presentViewController:errAlertController animated:YES completion:nil];
}
else
{

UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.delegate = self;
picker.allowsEditing = YES;
picker.sourceType = UIImagePickerControllerSourceTypeCamera;

[self presentViewController:picker animated:YES completion:NULL];

    }
}

- (IBAction)ChooseFromGallery:(id)sender {

UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.delegate = self;
picker.allowsEditing = YES;
picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

[self presentViewController:picker animated:YES completion:NULL];

}

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {


[picker dismissViewControllerAnimated:YES completion:^{
    UIImage *chosenImage = [info objectForKey:UIImagePickerControllerEditedImage];

    if ((chosenImage.size.height > 600.0) || (chosenImage.size.width > 800.0)){  // Need to scale down?
        UIGraphicsBeginImageContextWithOptions(CGSizeMake(800.0f, 600.0f), NO, 0.0);
        [chosenImage drawInRect:CGRectMake(0, 0, 800, 600)];
        UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        [self uploadPhoto:scaledImage];
    }
    else {
        [self uploadPhoto:chosenImage];
    }
    // "uploadPhoto" takes the JPG representation of the image and uploads it to a specific server path using HTTP POST. As mentioned, it worked in the simulator for iOS 11.1.
    }];

}

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {

[picker dismissViewControllerAnimated:YES completion:NULL];

}

score 0 · Answer 1 · answered Jun 19 '18 at 18:46

It turns out that the image actually was being updated in the uploadPhoto function, but it wasn't displaying until after the app had been destroyed and relaunched.

Apparently this effect resulted from the image processing being done in the completion block of dismissViewController, and not within the main block of didFinishPickingMediaWithInfo. Setting the completion block to NULL and moving the scaling and upload code fixed that problem.

UIImagePickerController works in iOS 11.1 but not in iOS 11.4

1 Answers1