UIBlurEffect 不影响它背后的 UIView

Question

我是这样定义的 UIVisualEffectView:

    UIApplication.sharedApplication().delegate?.window??.addSubview(self)

    let blurEffect = UIBlurEffect(style: .Light)
    let blurEffectView = UIVisualEffectView(effect: blurEffect)
    blurEffectView.frame = CGRectMake(20, 30, 300, 50)
    blurEffectView.backgroundColor = UIColor.yellowColor()
    addSubview(blurEffectView)

但这是一个结果：

但是正如你所看到的，navigationBar 的标题一点都不模糊。怎么了？

Answer 1

superview of blurEffectView 必须有：

alpha = 1
backgroundColor = UIColor.clearColor()

UIBlurEffect 不影响它背后的 UIView

UIBlurEffect doesn't affect on UIView behind it

ios

swift

uivisualeffectview