在 swift 中以编程方式在堆栈视图中添加标签和文本视图

Question

我怎样才能有一个标题，然后是几行文本，然后是一个标题，然后又一次又一次地以编程方式将几行文本限制在视图控制器的中间？

我的目标是为标题加粗，如果 textview 行也增加就好了。

我的想法是创建 2 个标签和 2 个文本视图。并按以下顺序将它们添加到文本视图中：label1、t1、label2、t2。

但是好像不行。我尽量避免多次定义相同的文本视图和标签。如果我复制它的定义两次而不是标签（也许它与视图相关？），textviews 会加起来

我尝试使用 UIbuttons 并且它有效。

这是我到目前为止尝试过的：

import UIKit

class HowToSetupProIGVC: UIViewController {
    deinit {print("deinit")}

    let textView: UITextView = {
        let textView = UITextView()
        textView.backgroundColor = .blue //bkgdColor
        textView.textAlignment = .left
        //textView.frame = CGRect(x: 5, y: 5, width: 5, height: 5)
        textView.tintColor = .black
        textView.translatesAutoresizingMaskIntoConstraints = false //enable autolayout
        textView.heightAnchor.constraint(equalToConstant: 100).isActive = true
        textView.widthAnchor.constraint(equalToConstant: 300).isActive = true
        return textView
    }()
    
    let label: UILabel = {
        let l = UILabel(frame:CGRect.zero)
        //l.frame = CGRect(x: 5, y: 5, width: 5, height: 5)
        l.backgroundColor = .green //bkgdColor
        l.font = UIFont.preferredFont(forTextStyle: .headline)
        l.translatesAutoresizingMaskIntoConstraints = false //enable autolayout
        l.heightAnchor.constraint(equalToConstant: 22).isActive = true
        l.widthAnchor.constraint(equalToConstant: 300).isActive = true
        return l
    }()
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.modalUI(arrowButton: false)
        self.view.backgroundColor = bkgdColor
        customStackHTSProIG ()

    }
    
    
}

extension HowToSetupProIGVC {
    
    func customStackHTSProIG () {
        
        let label1 = label
        let label2 = label
        
        let t1 = textView
        let t2 = textView
        
        label1.text = "Title1:"
        label2.text = "title2:"
        
        t1.text = """
            1. On your profile tap menu
            2. Tap settings
            3. Tap accounts
            4. Tap set up professional account
            """
            
        t2.text = """
            1. On your profile tap "Edit profile"
            2. Link your created page to your account
            """
        
        //StackView
        let stackHTS = UIStackView()
        stackHTS.axis = NSLayoutConstraint.Axis.vertical
        stackHTS.distribution = .fillEqually
        stackHTS.alignment = .center
        stackHTS.spacing = 5
        stackHTS.backgroundColor = .red
       
        
        //Add StackView + elements
        stackHTS.addArrangedSubview(label1)
        stackHTS.addArrangedSubview(t1)
        stackHTS.addArrangedSubview(label2)
        stackHTS.addArrangedSubview(t2)
        
        self.view.addSubview(stackHTS)
        
        
        //Constraints StackView
        stackHTS.translatesAutoresizingMaskIntoConstraints  = false
        stackHTS.centerYAnchor.constraint(equalTo: self.view.centerYAnchor).isActive = true
        stackHTS.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
        //stackHTS.heightAnchor.constraint(equalToConstant: 88).isActive = true
    }
    
}

Answer 1

UILabel

&

UITextView

都是用 Objective-C 编写的 UIKit 类。它们是引用类型，而不是值类型。

当你写下 -

let label1 = label
let label2 = label
        
let t1 = textView
let t2 = textView

label1

和

label2

都指向

UILabel

的同一个实例。

t1

和

t2

也是如此。

当你像这样添加它们时 -

//Add StackView + elements
stackHTS.addArrangedSubview(label1)
stackHTS.addArrangedSubview(t1)
stackHTS.addArrangedSubview(label2)
stackHTS.addArrangedSubview(t2)

您希望将 2 个标签和 2 个文本视图添加到 StackView。不过，您只添加了 1 个标签和 1 个文本视图。

您希望看到以下所有内容 -

        label1.text = "Title1:"
        label2.text = "title2:"
        
        t1.text = """
            1. On your profile tap menu
            2. Tap settings
            3. Tap accounts
            4. Tap set up professional account
            """
            
        t2.text = """
            1. On your profile tap "Edit profile"
            2. Link your created page to your account
            """

然而你只看到以下-

        label2.text = "title2:"
        
        t2.text = """
            1. On your profile tap "Edit profile"
            2. Link your created page to your account
            """

解决方案-

1. 创建两个单独的

   UITextView

   和

   UILabel

   实例，就像您已经为前两个所做的那样，并将这些新实例也添加到堆栈视图中。
2. 使用一个

   UILabel

   并删除其他所有内容。使用

   NSAttributedString

   API根据需要为不同的部分/段落设计文本样式并将其分配给

   UILabel.attributedText

   .