Question

我有这个UIView子类，我想用它来显示自定义视图。问题是我无法在我的视图中显示自定义CAGradientLayer ...我仍然将其视为红色条纹。

public class PSTLoadingBar : UIView {

private var loadingBarView: UIView!
private var gradientLayer: CAGradientLayer!

required public init(coder aDecoder: NSCoder) {
    fatalError("Not coder compliant")
}

public override var frame: CGRect {
    didSet {

        if frame == CGRect.zeroRect {
            return
        }

        loadingBarView.frame = frame
    }
}

// MARK: - Singleton
public class var sharedInstance: PSTLoadingBar {
    struct Singleton {
        static let instance = PSTLoadingBar(frame: CGRect.zeroRect)
    }
    return Singleton.instance
}

public override init(frame:CGRect) {

    super.init(frame:frame)

    loadingBarView = UIView()
    loadingBarView.backgroundColor = UIColor.redColor()

    gradientLayer = CAGradientLayer()
    gradientLayer.frame = loadingBarView.bounds
    gradientLayer.opacity = 1

    let color1 = UIColor(red: 67/255, green: 36/255, blue: 84/255, alpha: 1).CGColor
    let color2 = UIColor(red: 67/255, green: 36/255, blue: 84/255, alpha: 1).CGColor

    let colors = [color1, color2]

    gradientLayer.startPoint = CGPointMake(0,0.5)
    gradientLayer.endPoint = CGPointMake(1.0, 0.5)
    gradientLayer.colors = colors


    loadingBarView.layer.insertSublayer(gradientLayer, atIndex:0)

    addSubview(loadingBarView)

}

// MARK: - Public Methods
public class func show(parentView: UIView) {

    let loadingBar = PSTLoadingBar.sharedInstance

    let _view = UIApplication.sharedApplication().keyWindow?.rootViewController?.view

    if let _view = _view {

        loadingBar.frame = CGRectMake(0, 32, _view.bounds.width, 5)


        if loadingBar.superview == nil {
            _view.addSubview(loadingBar)
        }

    }
}

我已尝试在各种索引中添加子图层，我也尝试使用self.layer代替loadingBar.layer，但又没有成功。

我怀疑我需要覆盖UIView中的另一个方法，但我不确定是否是这种情况。

有什么想法吗？

Answer 1

创建loadingBarView时，其框架为CGRectZero - 一个零宽度和高度的矩形 - 这会导致渐变图层的宽度和高度同样为零，因此不会出现。无需在-layoutSubviews中添加图层 - 您只需将其框架更新为loadingBarView的边界。

无法添加CAGradientLayer以显示在UIView子类中

1 个答案: