动态backgroundColor UIImageView不更新iOS

当我移动第一个UIImageView的视图光标时，使用UIPanGestureRecognizer获得点rgb的颜色输出。使用这种颜色，我必须在第二个uiview中创建一个渐变，该渐变从起始颜色的左侧开始，然后到达白色的右侧。我注意到，在计算第一个RGB后，第二个UIView的backgroundColor的颜色被校正，但是在移动第一个UIView的光标并获得RGB颜色变化后，第二个UI的backgroundColor保持不变。动态backgroundColor UIImageView不更新iOS

@objc func wasDragged(gestureRecognizer: UIPanGestureRecognizer) { 

    if gestureRecognizer.state == .began || gestureRecognizer.state == .changed { 

     let translation = gestureRecognizer.translation(in: self.view) 

     gestureRecognizer.view!.center = CGPoint(x: gestureRecognizer.view!.center.x + translation.x, y: gestureRecognizer.view!.center.y + translation.y) 
     gestureRecognizer.setTranslation(CGPoint.zero, in: self.view) 
     let color = self.imageView.getPixelColorAt(point: gestureRecognizer.view!.center) 
     // color is correct 

     UIView.animate(withDuration: 1, delay: 0.0, options:[.repeat, .autoreverse], animations: { 
      self.gradientview.backgroundColor = UIColor.clear 
      self.gradientview.gradientBackground(from: color, to: UIColor.white, direction: GradientDirection.leftToRight) 
     // color is correct only first time, after remains unchanged 
     }, completion:nil) 

    } 
}

在扩展

创建渐变从这个例子开始 Programmatically create a UIView with color gradient

enum GradientDirection { 
    case leftToRight 
    case rightToLeft 
    case topToBottom 
    case bottomToTop 
} 

extension UIView { 
    func gradientBackground(from color1: UIColor, to color2: UIColor, direction: GradientDirection) { 
    let gradient = CAGradientLayer() 
    gradient.frame = self.bounds 
    gradient.colors = [color1.cgColor, color2.cgColor] 

    switch direction { 
    case .leftToRight: 
     gradient.startPoint = CGPoint(x: 0.0, y: 0.5) 
     gradient.endPoint = CGPoint(x: 1.0, y: 0.5) 
    case .rightToLeft: 
     gradient.startPoint = CGPoint(x: 1.0, y: 0.5) 
     gradient.endPoint = CGPoint(x: 0.0, y: 0.5) 
    case .bottomToTop: 
     gradient.startPoint = CGPoint(x: 0.5, y: 1.0) 
     gradient.endPoint = CGPoint(x: 0.5, y: 0.0) 
    default: 
     break 
    } 

    self.layer.insertSublayer(gradient, at: 0) 
} 
}

来源

2017-07-18 Adriana Carelli

你必须设置为零的所有子

self.gradientview.backgroundColor = UIColor.clear 
self.gradientview.layer.sublayers = nil 

UIView.animate(withDuration: 1, delay: 0.0, options:[.repeat, .autoreverse], animations: { 

      self.gradientview.gradientBackground(from: color, to: UIColor.white, direction: GradientDirection.leftToRight) 


    }, completion:nil)

来源

2017-07-18 14:31:53

动态backgroundColor UIImageView不更新iOS

回答

相关问题