swift label简单实现 走马灯

import UIKit

class CyclicScrollingADView : UIView {

varfirstLabel :UILabel?

varsecondLabel :UILabel?

varcurrentIndex :Int=0

varstate :Bool=true

lazyvartimer :Timer= {

lettimer =Timer.init(timeInterval:4, target:self, selector:#selector(CyclicScrollingADView.timeChange), userInfo:nil, repeats:true)

RunLoop.current.add(timer, forMode:RunLoopMode.commonModes)

returntimer;

}()

vardataSource : [NSAttributedString] = [] {

didSet{

firstLabel?.attributedText=dataSource[0]

currentIndex=0

self.timer.fire()

}

}

overrideinit(frame:CGRect) {

super.init(frame: frame)

self.clipsToBounds=true

firstLabel=UILabel.init(frame:CGRect.init(x:0, y:0, width: frame.size.width, height: frame.size.height))

firstLabel?.textColor=UIColor.white

firstLabel?.font=UIFont.boldSystemFont(ofSize:11)

secondLabel=UILabel.init(frame:CGRect.init(x:0, y: frame.size.height, width: frame.size.width, height: frame.size.height))

secondLabel?.textColor=UIColor.white

secondLabel?.font=UIFont.boldSystemFont(ofSize:11)

self.addSubview(firstLabel!)

self.addSubview(secondLabel!)

}

@objcfunctimeChange(){

currentIndex=currentIndex+1

ifcurrentIndex>=dataSource.count{

currentIndex=0

}

ifstate{

//展示第二个

self.secondLabel?.attributedText=self.dataSource[currentIndex]

UIView.animate(withDuration:0.5, animations: {

self.firstLabel?.frame=CGRect.init(x:0, y: -self.frame.size.height, width:self.frame.size.width, height:self.frame.size.height)

self.secondLabel?.frame=CGRect.init(x:0, y:0, width:self.frame.size.width, height:self.frame.size.height)

}) { (finish)in

self.firstLabel?.frame=CGRect.init(x:0, y:self.frame.size.height, width:self.frame.size.width, height:self.frame.size.height)

}

}else{

//展示第一个

self.firstLabel?.attributedText=self.dataSource[currentIndex]

UIView.animate(withDuration:0.5, animations: {

self.secondLabel?.frame=CGRect.init(x:0, y: -self.frame.size.height, width:self.frame.size.width, height:self.frame.size.height)

self.firstLabel?.frame=CGRect.init(x:0, y:0, width:self.frame.size.width, height:self.frame.size.height)

}) { (finish)in

self.secondLabel?.frame=CGRect.init(x:0, y:self.frame.size.height, width:self.frame.size.width, height:self.frame.size.height)

}

}

state= !state

}

requiredinit?(coder aDecoder:NSCoder) {

fatalError("init(coder:) has not been implemented")

}

}