Swift 委托(delegate)显示 nil

Question

我创建了一个 .xib 并将该 xib 添加到另一个 View 。我想在该 .xib 文件中添加委托(delegate)方法。这是我的代码:

.xib 文件

import UIKit

protocol CustomCheckBoxWithCrossDelegate {

    func deleteCustomCheckbox(itemToDelete: String)
}

class CustomCheckBoxWithCross: UIView {

    @IBOutlet weak var radioButton: UIButton!
    @IBOutlet weak var checkboxLbl: UILabel!
    @IBOutlet weak var checkboxCrossBtn: UIButton!

    var blockIndexForTheCrossButton: Int = 0
    var delegate: CustomCheckBoxWithCrossDelegate!

    override init(frame: CGRect) {
        super.init(frame: frame)
        loadViewFromNib ()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        loadViewFromNib ()
    }


    func loadViewFromNib() {
        let bundle = NSBundle(forClass: self.dynamicType)
        let nib = UINib(nibName: "CustomCheckBoxWithCross", bundle: bundle)
        let view = nib.instantiateWithOwner(self, options: nil)[0] as! UIView
        view.frame = bounds
        view.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]
        self.addSubview(view);
    }


    @IBAction func crossBtnTapped(sender: AnyObject) {
        print("Delegate --> \(delegate)")
        delegate!.deleteCustomCheckbox("hello")
    }
}

• 但是在“crossBtnTapped”方法中，我得到的委托(delegate)值为零。

谁能告诉我我做错了什么？

Answer 1

您必须在已实现该协议(protocol)的其他类中拥有 CustomCheckBoxWithCross 的实例。在该文件中将 CustomCheckBoxWithCross 实例的委托(delegate)属性设置为 self。