Question

I’m currently working on an iPad app to run in iOS 6

I’ve implemented a subclass of UIImagePickerController in my app that forces the camera to be in landscape orientation by overriding the - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation and - (NSUInteger)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window functions.

There seems to be a random chance that upon launching the image picker via presentViewController it will get caught on the camera “loading” screen. The one that looks like a closed camera shutter. The app will freeze on this screen unless you exit out of it or lock/unlock the screen, after which it will function correctly.

I also have a custom UI for the camera view. However I was noticing this issue before I added that in, so I think it’s unrelated.

Here’s what I have to open the picker:

if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
    self.modalController = [[CameraLandscapeImagePicker alloc] init];
    self.modalController.delegate = self;
    self.modalController.sourceType = UIImagePickerControllerSourceTypeCamera;
    self.modalController.mediaTypes = [NSArray arrayWithObjects:(NSString *) kUTTypeImage, nil];
    self.modalController.allowsEditing = NO;
    [self.viewController presentViewController:modalController animated:YES completion:nil];

    //add the overlaying view ui
    [self.modalController buildCustomOverlay];

    self.newMedia = YES;
}

Any help is appreciated.

[EDIT] – Update:
I have managed to figure out how to intentionally replicate this issue. Bellow are steps:

• tap my apps “capture” button to load up the camera
• exit the camera interface
• press the home button on the ipad
• open the app again by tapping it’s icon on home screen
• tap my apps “capture” button again
• camera freezes on shutter screen

I also noticed that it occurs even when connected to xcode.

I have modified my code so that the UIImagePickerController object is provided via a singleton. Previously I was creating a new UIImagePickerController object each time. This has not had any effect and I am still getting the same issue.
I’ve left the app running on the shutter screen for about 5 minutes now and it is still stuck.

Answer 1

I’ve finally figured out what the problem was.

In the custom UI view that I added as the cameraOverlayView of the UIImagePicker I had a custom NavigationBar view.
This view had it’s delegate set to the UIImagePicker and the delegate property used retain.

In the end it was a single word change from “retain” to “assign” to fix it:

@property (nonatomic,assign) id  delegate;

If you’re having a similar issue to this I recommend commenting out parts of your custom ui code to see what exactly is causing the problem.