简单实现slider控件

import UIKit

class ViewController: UIViewController,sliderDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let slider = Slider(frame: CGRect(x: 100, y: 100, width: 200, height: 100))
        //1.target
//        slider.addTarget(self, action: #selector(didmove(_:)), forControlEvents: .ValueChanged)
        //2.闭包
//        slider.didchange = {
//            sender in
//            print(sender.value)
//        }
        //3.协议
        slider.delegate = self
        self.view.addSubview(slider)
    }
    func didmove(sender:Slider){
        print(sender.value)
    }
    func sliderdelegate(slider: Slider) {
        print(slider.value)
    }
}

三种方法实现slider功能

import UIKit
//定义协议
protocol sliderDelegate {
    func sliderdelegate(slider: Slider)
}

class Slider: UIControl{
    
    //定义成员
    var didchange : ((Slider)->Void)!
    var minvalue : CGFloat = 0
    var maxvalue : CGFloat = 1
    var value : CGFloat = 0.5{
        didSet{
            if value > maxvalue{
                value = 1
            }else if value < minvalue{
                value = 0
            }
            self.setNeedsLayout()
        }
    }
    //创建对象
    var delegate : sliderDelegate!
    
    var sliderview = UIView()
    //构造函数
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.backgroundColor = UIColor.blueColor()
        sliderview.backgroundColor = UIColor.brownColor()
        self.addSubview(sliderview)
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        self.backgroundColor = UIColor.blueColor()
        sliderview.backgroundColor = UIColor.brownColor()
        
        self.addSubview(sliderview)
    }
    
    //定义触摸移动函数
    func Movesliderview(touches: NSSet){
    
        let touch = touches.anyObject() as! UITouch
        
        let location = touch.locationInView(self)
        value = (location.x / self.frame.size.width) * (maxvalue-minvalue) + minvalue
        
    }
    
    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
        print("bagan")
        Movesliderview(touches)
    }
    
    override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
        print("moved")
      
        Movesliderview(touches)
    }
    
    override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
        print("end")
        //1.通过闭包实现
//        if didchange != nil{
//            didchange(self)
//        }
        //2.通过sendActionsForContrloEvents实现
//        self.sendActionsForControlEvents(.ValueChanged)
        //3.通过协议实现
        if delegate != nil{
            delegate.sliderdelegate(self)
        }
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        let width = (value-minvalue)*self.frame.size.width/(maxvalue-minvalue)
        let rect = CGRect(x: 0, y: 0, width: width, height: self.frame.size.height)
        sliderview.frame = rect
    }

}