Question

I am writing an app that interfaces with the iPhone address book.

Here is the relevant section of my code (from UIImagePickerControllerDelegate)

-(void)imagePickerController:(UIImagePickerController *)picker 
       didFinishPickingImage:(UIImage *)image 
                 editingInfo:(NSDictionary *)editingInfo
{
    ABPersonSetImageData(record, (__bridge CFDataRef)UIImagePNGRepresentation(image), &error);
}

My app lets you take a picture with the camera (using UIImagePictureController), and then stores it as the contact for someone in your address book.

I’m finding that the operation above hangs for 5-10 seconds. 1) Is there a better approach? 2) Why is this so slow?

Answer 1

Saving as a JPEG:

UIImageJPEGRepresentation (UIImage *image, CGFloat compressionQuality);

will be faster than UIImagePNGRepresentation, especially if compressionQuality is set to a low value. However, this is still a CPU intensive process, so there’s no way to avoid the wait.

The best you can do is show a message that work is being done, so the interface doesn’t feel unresponsive. Use something like SVProgressHUD to do that.