Swift 如何使以前的标签消失并出现新的标签答案

【问题标题】：Swift How to make the previous label disappear and the new one to appearSwift 如何使以前的标签消失并出现新的标签
【发布时间】：2021-11-23 08:47:34
【问题描述】：

我正在制作我的第一个项目，这是一个真心话大冒险游戏，但是当我点击按钮打印真心话大冒险时，标签会相互堆叠。我如何使它以前的标签消失而新的标签单独存在。提前致谢



import UIKit
import PlaygroundSupport

public class ViewController: UIViewController {
    public override func loadView() {
        //adding baground
        super.loadView()
        let view = UIView()
        view.backgroundColor = .red
        self.view = view
        //dare button
        let dareButton = UIButton(frame: CGRect(x:300, y: 500, width: 100, height: 69))
        dareButton.layer.cornerRadius = 10
        dareButton.backgroundColor = #colorLiteral(red: 0.6352941393852234, green: 0.6470588445663452, blue: 0.886274516582489, alpha: 1.0)
        dareButton.setTitle("dare", for: UIControl.State.normal)
        dareButton.isUserInteractionEnabled = true
        dareButton.addTarget(self, action: #selector(dareButtonDidTap), for: .touchDown)
        view.addSubview(dareButton)
        self.view = view
        view.addSubview(dareButton)
    }
    @objc
    private func dareButtonDidTap() {
        let lbl = UILabel(frame: CGRect(x:95 , y:100, width: 325, height: 500))
        lbl.text = daresEng.randomElement()
        lbl.textColor = #colorLiteral(red: 0.6313725709915161, green: 0.6470588445663452, blue: 0.9058823585510254, alpha: 1.0)
        lbl.numberOfLines = 6
        view.addSubview(lbl)
    }
}

PlaygroundPage.current.needsIndefiniteExecution = true
PlaygroundPage.current.liveView = ViewController()

【问题讨论】：

标签： swift swift-playground

【解决方案1】：

标签是堆叠的，因为您每次单击dareButton 时都会创建一个新标签并将其添加到视图中，并且之前的标签不会从superView 中删除。因此您可以将标签移动到类级别并将其添加到loadView() 中的视图中。这样你只有一个标签，在dareButtonDidTap()中，你只需要改变这个标签的文字。

import UIKit
import PlaygroundSupport

public class ViewController: UIViewController {
    let lbl = UILabel(frame: CGRect(x:95 , y:100, width: 325, height: 500))
    
    public override func loadView() {
        //adding baground
        super.loadView()
        let view = UIView()
        view.backgroundColor = .red
        self.view = view
        //dare button
        let dareButton = UIButton(frame: CGRect(x:300, y: 500, width: 100, height: 69))
        dareButton.layer.cornerRadius = 10
        dareButton.backgroundColor = #colorLiteral(red: 0.6352941393852234, green: 0.6470588445663452, blue: 0.886274516582489, alpha: 1.0)
        dareButton.setTitle("dare", for: UIControl.State.normal)
        dareButton.isUserInteractionEnabled = true
        dareButton.addTarget(self, action: #selector(dareButtonDidTap), for: .touchDown)
        view.addSubview(dareButton)
        self.view = view
        
        view.addSubview(lbl)
        view.addSubview(dareButton)
    }
    
    @objc
    private func dareButtonDidTap() {
        lbl.text = daresEng.randomElement()
        lbl.textColor = #colorLiteral(red: 0.6313725709915161, green: 0.6470588445663452, blue: 0.9058823585510254, alpha: 1.0)
        lbl.numberOfLines = 6

    }
}

PlaygroundPage.current.needsIndefiniteExecution = true
PlaygroundPage.current.liveView = ViewController()

【讨论】：