UIImagePickerController: Detecting Camera button (shutter) pressed

Question

I would like to call a method that takes an NSNotification immediately after the user presses the camera shutter (i.e when the \"Preview\" tab bar has the buttons \"Retake\"

Answer 1

You CAN display it AFTER they choose the image.

- (void)imagePickerController:(UIImagePickerController *)picker 
        didFinishPickingImage:(UIImage *)image
                  editingInfo:(NSDictionary *)editingInfo
{
        //Display the UIAlertView
    [alertView show];
        //Just never use the image
}

If you don't want to use the image you really don't have to

Answer 2

To learn about camera button press event, you can fire a NSNotification for it.

// Add observer for when camera button is pressed
NSNotificationCenter.defaultCenter().addObserver(self, selector: @selector(yourFunctionToPerform), name: "_UIImagePickerControllerUserDidCaptureItem", object: nil)

Also add the following method to the ViewController where you are creating ImagePickerViewController:

-(void) yourFunctionToPerform{

    //Do what you want to do on Camera button tap event

}

I was searching for this problem too, the key/name for the event is really obscure.