在iOS中实现透明外观

Question

查看以下屏幕截图。我想知道如何在用户界面中获得半透明的外观。我怎样才能开始让我的UI看起来相似？

Answer 1

这是iOS 8中引入的新API.Apple的文档lives here和this question包含一些示例代码。注意 - 我在最后两个测试版中一直遇到困难，所以要为一些视觉错误做好准备。

对于iOS 7，有一个简单（和容忍）的黑客攻击，让你可以操纵UIToolBar来实现类似的效果，尽管控制力较弱。有一个开源项目here可以抽象一点。

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编辑 - 如果你使用Swift，这里有一些示例代码：

    // change .ExtraLight to .Light or .Dark to change the color of the blurred view
    let blurEffect = UIBlurEffect(style: .ExtraLight)
    let backgroundView = UIVisualEffectView(effect: blurEffect)
    backgroundView.frame = self.bounds
    backgroundView.autoresizingMask = .FlexibleWidth | .FlexibleHeight
    self.addSubview(backgroundView)

    let vibrancyView = UIVisualEffectView(effect: UIVibrancyEffect(forBlurEffect: blurEffect))
    vibrancyView.frame = self.bounds
    vibrancyView.autoresizingMask = .FlexibleWidth | .FlexibleHeight
    backgroundView.contentView.addSubview(vibrancyView)

    // Now, add your subviews to the vibrancyView.contentView
    // The effects are a bit tricky to get right with the color of your subviews, but here's how it's supposed to work:
    // - UIColor.whiteColor() shows up as pure, solid, (non-translucent) white
    // - UIColor.grayColor() shows up as essentially no change in the brightness of the underlying view, just blurred and vibrant