How to use UIBlurEffect with modal View Controllers?

Question

I have a UIViewController that presents another UIViewController modally. I want the modal view controller to have the blur/transparency that iOS 7 int

Answer 1

When using UIVisualEffectView, you don't need to generate a snapshot. Try removing "- (UIImage *)viewImage" and in the model view controller add a UIVisualEffectView with size matching the view controller view, and add all "control" views into the UIVisualEffectView's contentView.

- (void)viewDidLoad {
    [super viewDidLoad];

    UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];
    UIVisualEffectView *blurEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
    [blurEffectView setFrame:self.view.bounds];
    [self.view addSubview:blurEffectView];

    [blurEffectView.contentView addSubview:self.cancelButton];
    [blurEffectView.contentView addSubview:self.titleLabel];
    [blurEffectView.contentView addSubview:self.tableView];
}

https://developer.apple.com/library/prerelease/ios/documentation/UIKit/Reference/UIVisualEffectView/index.html

I haven't tried it with storyboards, but here's a tested working snippet. Might be a good place to start. Translating to objc should be pretty straightfoward

Here's the presenting view controller

import UIKit

class BaseViewController: UIViewController {

init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: NSBundle?) {
    super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
}

override func viewDidLoad() {
    super.viewDidLoad()

    var backgroundImage = UIImageView(image: UIImage(named: "image"))
    self.view.addSubview(backgroundImage)

    var button = UIButton(frame: CGRectMake(0, 100, 320, 50))
    button.setTitle("Lorem Ipsum", forState: UIControlState.Normal)
    button.backgroundColor = UIColor.redColor()
    button.addTarget(self, action: "onButtonTapped:", forControlEvents: UIControlEvents.TouchUpInside)

    self.view.addSubview(button)
}

func onButtonTapped(sender: UIButton?) {
    var modal = ModalViewController(nibName: nil, bundle: nil)
    modal.modalPresentationStyle = UIModalPresentationStyle.OverCurrentContext
    self.presentViewController(modal, animated: true, completion: {})
}
}

Here's the modal

import UIKit

class ModalViewController: UIViewController {

init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: NSBundle?) {
    super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
}

override func viewDidLoad() {
    super.viewDidLoad()

    self.view.backgroundColor = UIColor.clearColor()

    let effect = UIBlurEffect(style: UIBlurEffectStyle.Light)
    let blurView = UIVisualEffectView(effect: effect)

    blurView.frame = self.view.bounds

    self.view.addSubview(blurView)
}
}