objective c - iOS 7 UIImagePicker preview black screen

Question

When i try to load camera from my code, camera preview is black. If I wait for 10-20 seconds it will show real camera preview. I found several questions and some of them suggest that running some other code in background should be the reason for this. However I don't have any code running in background. How should I fix this?

This is my code where I run camera

UIImagePickerController *photoPicker = [[UIImagePickerController alloc] init];

photoPicker.delegate = self;
photoPicker.sourceType = UIImagePickerControllerSourceTypeCamera;
[self presentViewController:photoPicker animated:YES completion:NULL];

Answer 1

About 5 months ago my team discovered a memory leak with UIImageViewController in iOS7. Each instantiation slowed down the app exponentially (i.e. first alloc-init had a 1 second delay, second had a 2 second delay, third had a 5 second delay). Eventually, we were having 30-60 delays (similar to what you're experiencing).

We resolved the issue by subclassing UIImagePickerController and making it a Singleton. That way it was only ever initialized once. Now our delay is minimal and we avoid the leak. If subclassing isn't an option, try a class property in your viewController and just lazy load it like so.

-(UIImagePickerController *)imagePicker{
    if(!_imagePicker){
        _imagePicker = [[UIImagePickerController alloc]init];
        _imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
    }
    return _imagePicker;
}

Then you can just call it later like:

[self presentViewController:self.imagePicker animated:YES completion:nil];