iOS SDK: How to cause view to flip when switching cameras

Question

Fairly new at iOS/Objective C. I'm making mods to Apple's AVCam (video capture) sample code and would like to imitate the native camera's flip animation when switching between front and back cameras. It seems as if this would be easy but I can't get a handle on how it's done. Advice would be welcome.

Thanks!

Mark

Answer 1

It is indeed a simple task. All you need to do is call the method transitionWithView from UIView right before changing the previewView input.

If you're targeting iOS 8.0 or later, you can also easily add a blur effect.

Swift 2

let blurView = UIVisualEffectView(frame: previewView.bounds)
blurView.effect = UIBlurEffect(style: .Light)
previewView.addSubview(blurView)

UIView.transitionWithView(previewView, duration: 0.4, options: .TransitionFlipFromLeft, animations: nil) { (finished) -> Void in
    blurView.removeFromSuperview()
}

Swift 3, 4, 5

let blurView = UIVisualEffectView(frame: previewView.bounds)
blurView.effect = UIBlurEffect(style: .light)
previewView.addSubview(blurView)

UIView.transition(with: previewView, duration: 0.4, options: .transitionFlipFromLeft, animations: nil) { (finished) -> Void in
    blurView.removeFromSuperview()
}

Objective-C

UIVisualEffectView *blurView = [[UIVisualEffectView alloc] initWithFrame:_previewView.bounds];
blurView.effect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];
[_previewView addSubview:blurView];

[UIView transitionWithView:_previewView duration:0.4 options:UIViewAnimationOptionTransitionFlipFromLeft animations:nil completion:^(BOOL finished) {
    [blurView removeFromSuperview];
}];