模仿iPhone滑動開機動畫

時間 2019-11-11

原文原文鏈接

思路是:在view的layer層添加一個CAGradientLayer,同時添加一個mask,爲CAgradientLayer添加CABasicAnimation,就是白色滑動的動畫swift

1.建立繼承UIView子類: AnimatedMaskLabelide

添加屬性動畫

var gradientLayer = CAGradientLayer()
    let text: String = "Slide to see"
    let textAttributes: [String:AnyObject] = {
            let style = NSMutableParagraphStyle()
        style.alignment = .Center
        
        return [
            NSFontAttributeName: UIFont(name:"HelveticaNeue-Thin",size:25)!,
            NSParagraphStyleAttributeName:style
        ]
        }()

　　2.設置gradientLayer屬性:顏色,及相應的位置spa

func configureGradientLayer(){
        gradientLayer.startPoint = CGPointMake(0.0, 0.5)
        gradientLayer.endPoint = CGPointMake(1.0, 0.5)
        let colors = [
                    UIColor.blackColor().CGColor,
                    UIColor.whiteColor().CGColor,
                    UIColor.blackColor().CGColor
                ]
        gradientLayer.colors = colors
        
        let locations = [
                    0.25,0.5,0.75
                    ]
        gradientLayer.locations = locations
        
        
       
        
        
    }

　　設置frame:blog

override func layoutSubviews() {
        gradientLayer.frame = CGRectMake(-bounds.size.width, bounds.origin.y, 3 * bounds.size.width, bounds.size.height)
    }

　　3.添加Slide to see文字繼承

func addText(){
        UIGraphicsBeginImageContextWithOptions(frame.size, false, 0)
        text.drawInRect(bounds,withAttributes:textAttributes)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        
        let maskLayer = CALayer()
        maskLayer.backgroundColor = UIColor.clearColor().CGColor
        maskLayer.frame = CGRectOffset(bounds, bounds.size.width, 0)
        maskLayer.contents = image.CGImage
        gradientLayer.mask = maskLayer
    
    }

　　init的時候調用it

override init(frame:CGRect){
        super.init(frame: frame)
        self.configureGradientLayer()
        self.addText()
    }

　　4.最主要的動畫效果:basicAnimationio

override func didMoveToWindow() {
        
         layer.addSublayer(gradientLayer)
        let gradientAnimation = CABasicAnimation(keyPath: "locations")
        gradientAnimation.fromValue = [0.0,0.0,0.25]
        gradientAnimation.toValue = [0.75,1.0,1.0]
        gradientAnimation.duration = 3.0
        gradientAnimation.repeatCount = Float.infinity
        gradientLayer.addAnimation(gradientAnimation, forKey: nil)
    }

5.添加到UIViewController的view上table

override func viewDidLoad() {
        super.viewDidLoad()
        let animatedLabel = AnimatedMaskLabel(frame: CGRectMake(0, 100, view.frame.size.width, 30));
        animatedLabel.backgroundColor = UIColor.grayColor()
        view.addSubview(animatedLabel)
    }