APP中总会出现收到系统消息，按钮右上方出现带数字的小红点，特写一个demo以此记录

BadgeButton.gif

首先自定义一个UIButton，在UIButton中添加一个Label，存放消息数目

//
//  BadgeNumBtn.swift
//
//

import UIKit

class BadgeNumBtn: UIButton {
    private static let kInsets = UIEdgeInsets(top: 4, left: 3, bottom: 4, right: 3)
    private static let kFont = UIFont.systemFont(ofSize: 12)

    var badgeLabelNum = 0 {
        willSet {
            if newValue > 0 {
                badgeLabel.text = "\(newValue)"
                badgeLabel.backgroundColor = UIColor.red
                badgeLabel.textColor = UIColor.white
                badgeLabel.sizeToFit()
            } else {
                badgeLabel.text = ""
                badgeLabel.backgroundColor = UIColor.clear
                badgeLabel.textColor = UIColor.clear
            }
        }
    }
    
    
    private lazy var badgeLabel: UILabel = {
        let badgeLabel = UILabel()
        badgeLabel.textAlignment = .center
        badgeLabel.layer.masksToBounds = true
        badgeLabel.font = kFont
        return badgeLabel
    }()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.addSubview(badgeLabel)
    }
    
    required init?(coder aDecoder: NSCoder) {fatalError("init(coder:) has not been implemented")}

    override func layoutSubviews() {
        super.layoutSubviews()
        badgeLabel.frame = CGRect(x: 0, y: 0, width:badgeLabel.bounds.size.width + BadgeNumBtn.kInsets.top , height:  badgeLabel.bounds.size.width + BadgeNumBtn.kInsets.top * 2)
        badgeLabel.center = CGPoint(x: self.bounds.size.width, y: 0)
        badgeLabel.layer.cornerRadius = badgeLabel.bounds.size.width * 0.5

    }
}

使用方法直接继承自定义的BadgeButton,将消息数设置即可

    
    override func viewDidLoad() {
        super.viewDidLoad()

        
        var badgeBtn = BadgeNumBtn()//初始化

        //不带参
        badgeBtn.addTarget(self, action: #selector(badgeBtnClick(_:)), for: .touchUpInside)
        view.addSubview(badgeBtn)
        badgeBtn.backgroundColor = UIColor.cyan
        badgeBtn.snp.makeConstraints { (make) in
            make.right.equalTo(self.view).offset(-20)
            make.top.equalTo(self.view).offset(80)
            make.width.equalTo(100)
            make.height.equalTo(40)
        }
        
        badgeBtn.badgeLabelNum = 10
        
        codeView.addSubview(randomCaptchaView)
        randomCaptchaView.snp.makeConstraints { (make) in
            make.edges.equalTo(self.codeView)
        }
    }
    
    func badgeBtnClick(_ sender: BadgeNumBtn){
        
        sender.badgeLabelNum -= 1
        
    }

534E3B71-C534-4C2C-9149-272E7ED55E58.png