自定义下拉刷新控件

概述

用了很多的别人的下拉刷新控件，想写一个玩玩，自定义一个在使用的时候也会比较有意思。使应用更加的灵动一些，毕竟谁不喜欢各种动画恰到好处的应用呢。

使用方式如下：

tableview.refreshControl = XRefreshControl.init(refreshingBlock: {
    DispatchQueue.main.asyncAfter(deadline: .now() + 5) { [weak self] in
        self?.table.endRefreshing()
    }
})

下边展示一下效果。

然后又搞了一个比较炫酷的版本～，效果图如下：

继承 UIRefreshControl，然后再其上直接添加view就能实现需要的加载效果，尝试发现自定义的类需要把背景色设置一下，要不然会有一下拉整体都显示出来的问题，而且最好在view上再加一个view整体给铺上，在设置一个背景色，把小菊花给盖上。

简单版本代码

import Foundation
import UIKit
import SnapKit

class XRefreshControl: UIRefreshControl {
    var observation: NSKeyValueObservation?
    var isLocalRefreshing: Bool = false
    let indicator = UIProgressView(progressViewStyle: .bar)
    var refreshingBlock: (()->Void)?
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        observation = observe(
            \.frame,
             options: .new
        ) { [weak self] object, change in
            if self?.isRefreshing == true {
                if self?.isLocalRefreshing == false {
                    if self?.refreshingBlock != nil {
                        self?.refreshingBlock!()
                    }
                }
                self?.isLocalRefreshing = true
            } else {
                let height = change.newValue!.height
                self?.indicator.progress = min(Float(abs(height / 60)), 1)
            }
        }
    }
    convenience init(refreshingBlock: @escaping ()->Void) {
        self.init(frame: .zero)
        
        self.refreshingBlock = refreshingBlock
        
        self.layer.masksToBounds = true
        self.backgroundColor = .red
        
        let v = UIView()
        v.backgroundColor = .red
        
        let center = UIView()
        v.addSubview(center)
        
        let title = UILabel()
        title.text = "加载中"
        title.textColor = .black
        center.addSubview(title)
        
        indicator.layer.masksToBounds = true
        center.addSubview(indicator)
        
        self.addSubview(v)
        v.snp.makeConstraints { make in
            make.edges.equalToSuperview()
        }
        center.snp.makeConstraints { make in
            make.center.equalToSuperview()
            make.width.equalToSuperview()
        }
        indicator.snp.makeConstraints { make in
            make.top.equalToSuperview()
            make.width.height.equalTo(32)
            make.centerX.equalToSuperview()
        }
        title.snp.makeConstraints { make in
            make.top.equalTo(indicator.snp.bottom)
            make.bottom.equalToSuperview()
            make.centerX.equalToSuperview()
        }
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    deinit {
        observation = nil
    }
    
    override func endRefreshing() {
        super.endRefreshing()
        
        self.isLocalRefreshing = false
        indicator.progress = 0
    }
}

extension UITableView {
    func endRefreshing() {
        if ((self.refreshControl?.isKind(of: XRefreshControl.self)) != nil) {
            self.refreshControl?.endRefreshing()
        }
    }
}

加强版本代码

class XRefreshControl: UIRefreshControl {
    var observation: NSKeyValueObservation?
    var isLocalRefreshing: Bool = false
    let indicator = UIProgressView(progressViewStyle: .bar)
    var refreshingBlock: (()->Void)?
    var displayLink: CADisplayLink?
    var targetDuration: CGFloat = 3
    var fireDate: Date = .now
    var endRefreshingDate: Date = .now
    var title = UILabel()
    var colors: [UIColor] = [
        UIColor(hex: "ffbe0b"),
        UIColor(hex: "fb5607"),
        UIColor(hex: "ff006e"),
        UIColor(hex: "8338ec"),
        UIColor(hex: "3a86ff"),
    ]
    var speedViews: [UIView] = []
    var blockViews: [UIView] = []
    
    // 背景
    var contentView = UIView()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        observation = observe(
            \.frame,
             options: .new
        ) { [weak self] object, change in
            if self?.isRefreshing == true {
                if self?.isLocalRefreshing == false {
                    if self?.refreshingBlock != nil {
                        self?.refreshingBlock!()
                    }
                    self?.startAnimation()
                }
                self?.isLocalRefreshing = true
            } else {
                let height = change.newValue!.height
                self?.dragEffect(distance: height)
            }
        }
    }
    
    convenience init(refreshingBlock: @escaping ()->Void) {
        self.init(frame: .zero)
        
        self.refreshingBlock = refreshingBlock
        
        self.layer.masksToBounds = true
        self.backgroundColor = .white
        
        contentView.backgroundColor = .red
        self.addSubview(contentView)
        
        let center = UIView()
        contentView.addSubview(center)
        
        title.text = "下拉加载"
        title.textColor = .black
        center.addSubview(title)
        
        center.addSubview(indicator)
        
        for _ in 0...6 {
            let v = UIView()
            v.backgroundColor = .white
            speedViews.append(v)
            contentView.addSubview(v)
        }
        
        for _ in 0..<10 {
            let v = UIView()
            v.backgroundColor = .white
            blockViews.append(v)
            contentView.addSubview(v)
        }
        
        contentView.snp.makeConstraints { make in
            make.edges.equalToSuperview()
        }
        center.snp.makeConstraints { make in
            make.center.equalToSuperview()
        }
        indicator.snp.makeConstraints { make in
            make.left.top.right.equalToSuperview()
            make.width.equalTo(120)
            make.height.equalTo(6)
        }
        title.snp.makeConstraints { make in
            make.top.equalTo(indicator.snp.bottom).offset(10)
            make.bottom.equalToSuperview()
            make.centerX.equalToSuperview()
        }
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    deinit {
        observation = nil
        self.displayLink?.remove(from: RunLoop.current, forMode: .common)
    }
    
    func dragEffect(distance: CGFloat) {
        let diff = abs(endRefreshingDate.timeIntervalSinceNow)
        if diff < 0.5 {
            return
        }
        
        let precent = min(abs(distance/140),1)
        let value = precent * 8 * CGFloat.pi
        self.indicator.progress = 1
        let opacity = Float(sin(value))
//        print("opacity \(opacity)")
        self.indicator.layer.opacity = opacity
        self.title.text = "下拉加载"
        
        for i in 0..<3 {
            let xx = (self.frame.size.width / 12.0) * CGFloat(i+1)
            var yy = abs(distance/2)-2
            yy += sin(distance/10 + CGFloat(i+1)*10)*6
            speedViews[i].frame = .init(x: xx, y: yy, width: 2, height: 4)
        }
        for i in 3..<6 {
            var x = (self.frame.size.width / 12.0) * CGFloat(i+1-3)
            x += self.frame.width * 2.0 / 3.0
            var yy = abs(distance/2)-2
            yy += sin(distance/10 + CGFloat(i+1-3)*10)*6
            speedViews[i].frame = .init(x: x, y: yy, width: 2, height: 4)
        }
        for i in 0..<blockViews.count {
            blockViews[i].frame = .init(x: 0, y: 0, width: 0, height: 0)
        }
    }
    
    func startAnimation() {
        displayLink = CADisplayLink(target: self, selector: #selector(update))
        displayLink?.add(to: RunLoop.current, forMode: .common)
        fireDate = .now
        self.indicator.layer.opacity = 1
        self.indicator.progress = 1
        self.title.text = "加载中"
        
        let width = self.frame.width
        for i in 0..<blockViews.count {
            let size = CGFloat.random(in: 4...8)
            let x = CGFloat.random(in: 0...width)
            blockViews[i].frame = .init(x: x, y: 0, width: size, height: size)
        }
    }
    
    @objc func update(_ displayLink: CADisplayLink) {
        let diff = abs(fireDate.timeIntervalSinceNow)
        var precent = diff / targetDuration
        precent = min(precent, 1)
        self.indicator.progress = Float(precent)
        contentView.backgroundColor = colors[Int(diff*3)%colors.count]
        
        for i in 0..<3 {
            var xx = (self.frame.size.width / 12.0) * CGFloat(i+1)
            var yy = self.frame.height/2-12
            if i == 1 {
                yy += sin(CGFloat(diff)*6) * 2
                xx += sin(CGFloat(diff)*6)
            } else {
                yy += sin(CGFloat(diff)*6) * 4
                xx += sin(CGFloat(diff)*6 + CGFloat(i+1))
            }
            speedViews[i].frame = .init(x: xx, y: yy, width: 2, height: 24)
        }
        for i in 3..<6 {
            var xx = (self.frame.size.width / 12.0) * CGFloat(i+1-3)
            xx += self.frame.width * 2.0 / 3.0
            var yy = self.frame.height/2-12
            if i == 4 {
                yy += sin(CGFloat(diff)*6) * 2
                xx += sin(CGFloat(diff)*6)
            } else {
                yy += sin(CGFloat(diff)*6) * 4
                xx += sin(CGFloat(diff)*6 + CGFloat(i+1-3))
            }
            
            speedViews[i].frame = .init(x: xx, y: yy, width: 2, height: 24)
        }
        
        for i in 0..<self.blockViews.count {
            var x = self.blockViews[i].frame.origin.x
            var y = self.blockViews[i].frame.origin.y + self.blockViews[i].frame.width / 4
            if y > self.contentView.frame.height {
                y = 0
                x = CGFloat.random(in: 0...self.contentView.frame.width)
            }
            self.blockViews[i].frame = .init(origin: .init(x: x, y: y), size: self.blockViews[i].frame.size)
        }
    }
    
    override func endRefreshing() {
        super.endRefreshing()
        
        self.isLocalRefreshing = false
        self.displayLink?.remove(from: RunLoop.current, forMode: .common)
        endRefreshingDate = .now
        self.title.text = "加载完毕"
    }
}
extension UITableView {
    func endRefreshing() {
        if ((self.refreshControl?.isKind(of: XRefreshControl.self)) != nil) {
            self.refreshControl?.endRefreshing()
        }
    }
}
extension UIColor {
    /// 使用 #FFFFFF 来初始化颜色
    convenience init(hex: String, alpha: CGFloat = 1.0) {
        var hexFormatted: String = hex.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines).uppercased()

        if hexFormatted.hasPrefix("#") {
            hexFormatted = String(hexFormatted.dropFirst())
        }
        
        if hexFormatted.hasPrefix("0x") {
            hexFormatted = String(hexFormatted.dropFirst())
            hexFormatted = String(hexFormatted.dropFirst())
        }

        assert(hexFormatted.count == 6, "Invalid hex code used.")

        var rgbValue: UInt64 = 0
        Scanner(string: hexFormatted).scanHexInt64(&rgbValue)

        self.init(red: CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0,
                  green: CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0,
                  blue: CGFloat(rgbValue & 0x0000FF) / 255.0,
                  alpha: alpha)
    }
}

参考地址