核心动画（Core Animation）

CAAnimation继承结构

核心动画

• 注意：上图中的黑色虚线代表”继承”某个类，红色虚线代表“遵守”某个协议

• 四大类
  1.CABasicAnimation：基础动画

2.CAAnimationGroup：组动画

3.CAKeyframeAnimation：关键帧动画

4.CATransition：转场动画

注：Core Animation是直接作用在CALayer上的，并非UIView

CAAnimation属性介绍

• duration：动画的持续时间
• repeatCount：动画的重复次数
• repeatDuration：动画的重复时间
• removedOnCompletion：默认为YES，代表动画执行完毕后就从图层上移除，图形会恢复到动画执行前的状态。如果想让图层保持显示动画执行后的状态，那就设置为NO，不过还要设置fillMode为kCAFillModeForwards
• fillMode：决定当前对象在非active时间段的行为.比如动画开始之前,动画结束之后
• beginTime：可以用来设置动画延迟执行时间，若想延迟2s，就设置为CACurrentMediaTime()+2，CACurrentMediaTime()为图层的当前时间
• timingFunction：速度控制函数，控制动画运行的节奏

  • kCAMediaTimingFunctionLinear（线性）：匀速，给你一个相对静态的感觉

  • kCAMediaTimingFunctionEaseIn（渐进）：动画缓慢进入，然后加速离开

  • kCAMediaTimingFunctionEaseOut（渐出）：动画全速进入，然后减速的到达目的地

  • kCAMediaTimingFunctionEaseInEaseOut（渐进渐出）：动画缓慢的进入，中间加速，然后减速的到达目的地。这个是默认的动画行为。

CABasicAnimation

• 效果图

  
  CABasicAnimation.gif

• 代码

import UIKit

 class ViewController: UIViewController {

    var layer :CALayer?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.addSubview(redView)
        layer = redView.layer
    }
    
    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
        
        let basicAni = CABasicAnimation()
        basicAni.keyPath = "position.x"
        //      basicAni.fromValue = (10) // 从哪
        //            basicAni.toValue = (300) // 到哪
        //        basicAni.duration = 4 //动画执行的时间，默认0.25
        basicAni.byValue = (10); // 在自身的基础上累加
        // 不希望核心动画回到原来的位置
        basicAni.fillMode = kCAFillModeForwards;
        basicAni.removedOnCompletion = false;
        
        self.layer?.addAnimation(basicAni, forKey: nil)
        print(self.redView.frame.origin.x)
    }
    //懒加载redView
    lazy var redView : UIView = {
    
        let redView = UIView(frame:CGRectMake(100, 100, 100, 100))
        redView.backgroundColor = UIColor.redColor()
        
        return redView
    }()
}

由打印结果可看出虽然redView的layer的frame在变化，但redView的没变

CAKeyframeAnimation

• 效果

keyFrameAnimation.gif

• 代码

import UIKit

class ViewController: UIViewController {

    var layer :CALayer?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.addSubview(redView)
        layer = redView.layer
    }
    
    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
   
        let keyframeAni = CAKeyframeAnimation()
        
        keyframeAni.keyPath = "position";
        
        //创建路径
        let path = UIBezierPath(ovalInRect: CGRectMake(100, 100, 160, 160))

        keyframeAni.path = path.CGPath
        
        keyframeAni.duration = 2
        
        keyframeAni.repeatCount = 300
        
        self.layer?.addAnimation(keyframeAni, forKey: nil)
        
    }
 
    
    //懒加载redView
    lazy var redView : UIView = {
    
        let redView = UIView(frame:CGRectMake(100, 100, 30, 30))
        redView.backgroundColor = UIColor.redColor()
        
        return redView
    }()
}

• CAAnimationGroup

• 演示

  
  group.gif

• 代码

 import UIKit

 class ViewController: UIViewController {

    var layer :CALayer?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.addSubview(redView)
        layer = redView.layer
    }
    
    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
 

        let group = CAAnimationGroup()
        
        let keyframeAni = CAKeyframeAnimation()
        
        keyframeAni.keyPath = "position"
        
        let path = UIBezierPath(arcCenter:CGPointMake(200, 200) , radius: 80, startAngle: 0, endAngle: CGFloat(2.0 * M_PI), clockwise: true)
        
        keyframeAni.path = path.CGPath
        
        let basicAni = CABasicAnimation()
        
        basicAni.keyPath = "transform.rotation"
        
        basicAni.byValue = (M_PI * 2 * 3)
        
        group.animations = [keyframeAni,basicAni]
        
        group.duration = 3
        
        group.repeatCount = Float(INT_MAX)
        
        self.layer?.addAnimation(group, forKey: nil)
        
    }
 
    
    //懒加载redView
    lazy var redView : UIView = {
    
        let redView = UIView(frame:CGRectMake(100, 100, 30, 30))
        redView.backgroundColor = UIColor.redColor()
        
        return redView
     }()
    }

• CATransition

• type属性

type