iOS 7 Translucent Modal View Controller

Ian picture Ian · Oct 4, 2013 · Viewed 35.6k times · Source

The App Store app on iOS 7 uses a frosted glass-type effect where it is possible to see the view behind. Is this using an API built into iOS 7 or is it custom code. I was hoping it would be the former but I can't see any obvious references in the documentation. Obvious things like (like setting the alpha property on the modal view) don't seem to have any effect.

To see an example, open the App Store app and press the button at the top-right.

App Store home page Modal view in the App Store

Answer

Sebastian Hojas picture Sebastian Hojas · Mar 4, 2014

With the release of iOS 8.0, there is no need for getting an image and blurring it anymore. As Andrew Plummer pointed out, you can use UIVisualEffectView with UIBlurEffect.

UIViewController * contributeViewController = [[UIViewController alloc] init];
UIBlurEffect * blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];
UIVisualEffectView *beView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
beView.frame = self.view.bounds;

contributeViewController.view.frame = self.view.bounds;
contributeViewController.view.backgroundColor = [UIColor clearColor];
[contributeViewController.view insertSubview:beView atIndex:0];
contributeViewController.modalPresentationStyle = UIModalPresentationOverCurrentContext;

[self presentViewController:contributeViewController animated:YES completion:nil];

Solution that works before iOS 8

I would like to extend on rckoenes' answer:

As emphasised, you can create this effect by:

  1. Convert the underlying UIView to an UIImage
  2. Blur the UIImage
  3. Set the UIImage as background of your view.

enter image description here


Sounds like a lot of work, but is actually done pretty straight-forward:

1. Create a category of UIView and add the following method:

-(UIImage *)convertViewToImage
{
    UIGraphicsBeginImageContext(self.bounds.size);
    [self drawViewHierarchyInRect:self.bounds afterScreenUpdates:YES];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return image;
}

2. Make an image of the current view and blur it by using Apple's Image Effect category (download)

UIImage* imageOfUnderlyingView = [self.view convertViewToImage];
imageOfUnderlyingView = [imageOfUnderlyingView applyBlurWithRadius:20
                             tintColor:[UIColor colorWithWhite:1.0 alpha:0.2]
                 saturationDeltaFactor:1.3
                             maskImage:nil];

3. Set it as background of your overlay.

-(void)viewDidLoad
{
   self.view.backgroundColor = [UIColor clearColor];
   UIImageView* backView = [[UIImageView alloc] initWithFrame:self.view.frame];
   backView.image = imageOfUnderlyingView;
   backView.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.6];
   [self.view addSubview:backView];
}