如何从 UI 按钮制作 UIBarButtonItem class？

Question

我是初学者，想做一个像上图一样有badge的top bar button，在网上搜索了一下，实现了SSBadgeButton就可以在button上做badge了以下

import UIKit

class SSBadgeButton: UIButton {

    var badgeLabel = UILabel()

    var badge: String? {
        didSet {
            addBadgeToButon(badge: badge)
        }
    }

    public var badgeBackgroundColor = UIColor.red {
        didSet {
            badgeLabel.backgroundColor = badgeBackgroundColor
        }
    }

    public var badgeTextColor = UIColor.white {
        didSet {
            badgeLabel.textColor = badgeTextColor
        }
    }

    public var badgeFont = UIFont.systemFont(ofSize: 12.0) {
        didSet {
            badgeLabel.font = badgeFont
        }
    }

    public var badgeEdgeInsets: UIEdgeInsets? {
        didSet {
            addBadgeToButon(badge: badge)
        }
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        addBadgeToButon(badge: nil)
    }

    func addBadgeToButon(badge: String?) {
        badgeLabel.text = badge
        badgeLabel.textColor = badgeTextColor
        badgeLabel.backgroundColor = badgeBackgroundColor
        badgeLabel.font = badgeFont
        badgeLabel.sizeToFit()
        badgeLabel.textAlignment = .center
        let badgeSize = badgeLabel.frame.size

        let height = max(18, Double(badgeSize.height) + 5.0)
        let width = max(height, Double(badgeSize.width) + 10.0)

        var vertical: Double?, horizontal: Double?
        if let badgeInset = self.badgeEdgeInsets {
            vertical = Double(badgeInset.top) - Double(badgeInset.bottom)
            horizontal = Double(badgeInset.left) - Double(badgeInset.right)

            let x = (Double(bounds.size.width) - 10 + horizontal!)
            let y = -(Double(badgeSize.height) / 2) - 10 + vertical!
            badgeLabel.frame = CGRect(x: x, y: y, width: width, height: height)
        } else {
            let x = self.frame.width - CGFloat((width / 2.0))
            let y = CGFloat(-(height / 2.0))
            badgeLabel.frame = CGRect(x: x, y: y, width: CGFloat(width), height: CGFloat(height))
        }

        badgeLabel.layer.cornerRadius = badgeLabel.frame.height/2
        badgeLabel.layer.masksToBounds = true
        addSubview(badgeLabel)
        badgeLabel.isHidden = badge != nil ? false : true
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        self.addBadgeToButon(badge: nil)
        fatalError("init(coder:) has not been implemented")
    }
}

我们可以看到 SSBadgeButton 是 UIButton，我需要将 SSBadgeButton 转换为 UIBarButtonItem。这样做的目的是使 UIBarButtonItem class 可以在界面生成器中作为自定义 class 访问，如下图

Answer 1

您可以使用自定义按钮创建 UIBarButtonItem

let button = SSBadgeButton(frame: CGRect(x: 0, y: 0, width: 30, height: 30)
let barBtnItem = UIBarButtonItem(customView: button)

Answer 2

您不需要将 UIButton 转换为 UIBarButtonItem，您始终可以使用 UIButton 创建 UIBarbuttonItem，如下所示

    let button = UIButton()
    button.setTitle("ABCD", for: .normal)
    let uiBarButtonItem = UIBarButtonItem(customView: button)
    self.navigationItem.leftBarButtonItems = [uiBarButtonItem]

您将使用 SSBadgeButton 仅此而已

而不是 UIButton

希望对您有所帮助

如何从 UI 按钮制作 UIBarButtonItem class？

how to make UIBarButtonItem class from UI Button?

ios

swift

uibarbuttonitem