swift2.0 跑马灯

最近公司项目需要写一个跑马灯的效果，android的直接设置属性就可以了。为啥ios没有呢，我想一定是乔帮主认为跑马灯是个反人类的设计。哈哈，随便扯个蛋，进入正题。实现原理就是使用2个label，一前一后2个label的layer进行平行移动，当后面label的layer移动到前面的位置，动画再复原，重复执行。这样一个基本的跑马灯就实现了，我在此基础上给跑马灯加了，开始，停止，暂停，继续，4个动作。

动画代码

// MARK: - 跑马灯动画实现过程
func marqueeAnimation() {
let frontAnima = CABasicAnimation()
frontAnima.keyPath = "position"
frontAnima.fromValue = NSValue(CGPoint: CGPoint(x:  self.frontLabel.frame.width / 2 , y: self.frame.height / 2))
frontAnima.toValue = NSValue(CGPoint: CGPoint(x: -1 * self.frontLabel.frame.width / 2, y: self.frame.height / 2))
frontAnima.duration = self.time
frontAnima.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionLinear)
frontAnima.repeatCount = MAXFLOAT

let behindAnima = CABasicAnimation()
behindAnima.keyPath = "position"
behindAnima.fromValue = NSValue(CGPoint: CGPoint(x:  self.frontLabel.frame.width / 2 * 3 , y: self.frame.height / 2))
behindAnima.toValue = NSValue(CGPoint: CGPoint(x:  self.frontLabel.frame.width / 2, y: self.frame.height / 2))
behindAnima.duration = self.time
behindAnima.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionLinear)
behindAnima.repeatCount = MAXFLOAT

self.frontLabel.layer.addAnimation(frontAnima, forKey: "frontAnima")
self.behindLabel.layer.addAnimation(behindAnima, forKey: "behindAnima")
}

开始

// MARK: - 开始跑马灯动画
func start(){
if isRun == false {
isRun = true
isSuspend = false
frontLabel.layer.timeOffset = 0.0
behindLabel.layer.timeOffset = 0.0
frontLabel.layer.speed = 1.0
behindLabel.layer.speed = 1.0
frontLabel.layer.beginTime = 0.0
behindLabel.layer.beginTime = 0.0
marqueeAnimation()
}
}

停止

// MARK: - 停止跑马灯动画
func stop() {
if isRun {
isRun = false
frontLabel.layer.removeAnimationForKey("frontAnima")
behindLabel.layer.removeAnimationForKey("behindAnima")
}
}

暂停

// MARK: -  暂停动画
func suspend() {
if isRun && isSuspend == false {
isSuspend = true

let frontPauseTime = frontLabel.layer.convertTime(CACurrentMediaTime(), fromLayer: nil)
frontLabel.layer.speed = 0.0
frontLabel.layer.timeOffset = frontPauseTime

let behindPauseTime = behindLabel.layer.convertTime(CACurrentMediaTime(), fromLayer: nil)
behindLabel.layer.speed = 0.0
behindLabel.layer.timeOffset = behindPauseTime

}
}

继续

// MARK: - 继续动画
func continuation() {
if isRun && isSuspend {
isSuspend = false
let frontPauseTime = frontLabel.layer.timeOffset
frontLabel.layer.speed = 1.0
frontLabel.layer.timeOffset = 0.0
frontLabel.layer.beginTime = 0.0
let frontTimeSincePause = frontLabel.layer.convertTime(CACurrentMediaTime(), fromLayer: nil)  - frontPauseTime
frontLabel.layer.beginTime = frontTimeSincePause

let behindPauseTime = behindLabel.layer.timeOffset
behindLabel.layer.speed = 1.0
behindLabel.layer.timeOffset = 0.0
behindLabel.layer.beginTime = 0.0
let behindTimeSincePause = behindLabel.layer.convertTime(CACurrentMediaTime(), fromLayer: nil)  - behindPauseTime
behindLabel.layer.beginTime = behindTimeSincePause

}
}

总结

上面就是我实现跑马灯的核心代码。在网上找了一番都没有遇到满意的跑马灯代码，就自己写了一份，欢迎大家前来交流。如果是使用oc的，那就需要你自己翻译成oc代码了_ swift跑马灯代码