把这个模糊视图放到imageView上。下面是Objective-C中的一个例子:

UIVisualEffect *blurEffect;
blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];

UIVisualEffectView *visualEffectView;
visualEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];

visualEffectView.frame = imageView.bounds;
[imageView addSubview:visualEffectView];

迅速:

var visualEffectView = UIVisualEffectView(effect: UIBlurEffect(style: .Light))    

visualEffectView.frame = imageView.bounds

imageView.addSubview(visualEffectView)

这里是如何使用UIVibrancyEffect和UIBlurEffect与UIVisualEffectView

objective - c:

// Blur effect
UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];
UIVisualEffectView *blurEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
[blurEffectView setFrame:self.view.bounds];
[self.view addSubview:blurEffectView];

// Vibrancy effect
UIVibrancyEffect *vibrancyEffect = [UIVibrancyEffect effectForBlurEffect:blurEffect];
UIVisualEffectView *vibrancyEffectView = [[UIVisualEffectView alloc] initWithEffect:vibrancyEffect];
[vibrancyEffectView setFrame:self.view.bounds];

// Label for vibrant text
UILabel *vibrantLabel = [[UILabel alloc] init];
[vibrantLabel setText:@"Vibrant"];
[vibrantLabel setFont:[UIFont systemFontOfSize:72.0f]];
[vibrantLabel sizeToFit];
[vibrantLabel setCenter: self.view.center];

// Add label to the vibrancy view
[[vibrancyEffectView contentView] addSubview:vibrantLabel];

// Add the vibrancy view to the blur view
[[blurEffectView contentView] addSubview:vibrancyEffectView];

迅速:

// Blur Effect
let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.dark)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
blurEffectView.frame = view.bounds
view.addSubview(blurEffectView)

// Vibrancy Effect
let vibrancyEffect = UIVibrancyEffect(blurEffect: blurEffect)
let vibrancyEffectView = UIVisualEffectView(effect: vibrancyEffect)
vibrancyEffectView.frame = view.bounds

// Label for vibrant text
let vibrantLabel = UILabel()
vibrantLabel.text = "Vibrant"
vibrantLabel.font = UIFont.systemFont(ofSize: 72.0)
vibrantLabel.sizeToFit()
vibrantLabel.center = view.center

// Add label to the vibrancy view
vibrancyEffectView.contentView.addSubview(vibrantLabel)

// Add the vibrancy view to the blur view
blurEffectView.contentView.addSubview(vibrancyEffectView)

您还可以使用界面构建器为简单的情况轻松地创建这些效果。因为视图的z值将取决于它们在文档大纲中列出的顺序，你可以在你想要模糊的视图之前将UIVisualEffectView拖到文档大纲上。这会自动创建一个嵌套的UIView，它是给定UIVisualEffectView的contentView属性。在这个视图中嵌套你想要出现在模糊顶部的东西。

你也可以很容易地利用振动UIVisualEffect，它会自动在文档大纲中创建另一个嵌套的UIVisualEffectView，默认启用了振动。然后你可以添加一个标签或文本视图到嵌套的UIView(同样，UIVisualEffectView的contentView属性)，以达到与“> slide to unlock”UI元素相同的效果。

我更喜欢通过故事板来创建视觉效果——没有代码用于创建或维护UI元素。它还为我提供了完整的横向支持。我已经做了一个使用UIVisualEffects模糊和动态的小演示。

在Github上演示

如果有人想要Swift的答案:

var blurEffect = UIBlurEffect(style: UIBlurEffectStyle.Dark) // Change .Dark into .Light if you'd like.

var blurView = UIVisualEffectView(effect: blurEffect)

blurView.frame = theImage.bounds // 'theImage' is an image. I think you can apply this to the view too!

更新:

到目前为止，它是在IB下可用的，所以你不需要为它编写任何代码:)

-(void) addBlurEffectOverImageView:(UIImageView *) _imageView
{
    UIVisualEffect *blurEffect;
    blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];

    UIVisualEffectView *visualEffectView;
    visualEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];

    visualEffectView.frame = _imageView.bounds;
    [_imageView addSubview:visualEffectView];
}