Question

我有两个垂直的堆栈视图，一个以下列方式嵌套在另一个视图中：

StackView #1
   UITextField
   StackView #2 (nothing in this one)
   UIButton

我试图以编程方式将UITextFields插入我的StackView＃2，但是当我这样做时，什么也没发生。我看不到插入任何视图，屏幕上也没有任何反应。

StackView＃1设置为“对齐填充”，“按比例分配”。我的StackView＃2都是Fill。

当我尝试添加到StackView＃2时，我没有收到约束警告，所以我很好奇为什么什么也没发生。这是我的添加方式：

let textField = UITextField(frame: CGRect(x: 0, y: 0, width: 285, height: 30))
textField.placeholder = "Name"
subtasksStackView.addArrangedSubview(textField)

Answer 1

以下是一些您可以添加到Playground的代码。它包含的结构与您问题中的结构相同，但是有细微的差别；我还使用了第三个堆栈视图，该堆栈视图仅用于包装所有内容，这样我就可以将内容放置在视图控制器的顶部，而不会对包含的元素进行任何不必要的调整大小（拉伸，收缩）。我怀疑这可能是一个约束问题，但这应该可以帮助您将当前的实现与可行的解决方案进行比较。

import UIKit
import PlaygroundSupport


class ViewController: UIViewController {

    // MARK: - Properties

    let mainStackView = UIStackView()
    let stackViewOne = UIStackView()
    let textFieldOne = UITextField()
    let stackViewTwo = UIStackView()
    let buttonOne = UIButton(type: .system)

    // MARK: - Lifecycle

    override func viewDidLoad() {
        view.backgroundColor = .white
        // mainStackView is used so that the UI elements can be displayed at the top of the stack view without being stretched to fill the entire view controller.
        mainStackView.axis = .horizontal
        mainStackView.alignment = .top
        mainStackView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(mainStackView)
        // mainStackView needs constraints to the view controller's view.
        mainStackView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
        mainStackView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
        mainStackView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
        mainStackView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
        // Configure the first stack view. This is StavkView#1, in your case.
        stackViewOne.axis = .vertical
        stackViewOne.alignment = .fill
        stackViewOne.distribution = .fillProportionally
        mainStackView.addArrangedSubview(stackViewOne)
        // Configure the first text field.
        textFieldOne.heightAnchor.constraint(equalToConstant: 30).isActive = true
        textFieldOne.placeholder = "Text Field One"
        textFieldOne.borderStyle = .line
        stackViewOne.addArrangedSubview(textFieldOne)
        stackViewOne.addArrangedSubview(stackViewTwo)
        // Configure the button.
        buttonOne.heightAnchor.constraint(equalToConstant: 44).isActive = true
        buttonOne.setTitle("Button", for: .normal)
        buttonOne.tintColor = .black
        stackViewOne.addArrangedSubview(buttonOne)
        // Add the second text field to the nested stack view. This is StackView#2, in your case.
        let textFieldTwo = UITextField(frame: CGRect(x: 0, y: 0, width: 285, height: 30))
        textFieldTwo.heightAnchor.constraint(equalToConstant: 30).isActive = true
        textFieldTwo.placeholder = "Name"
        textFieldTwo.borderStyle = .line
        stackViewTwo.addArrangedSubview(textFieldTwo)
    }

}

let viewController = ViewController(nibName: nil, bundle: nil)
viewController.view.frame = CGRect(x: 0, y: 0, width: 1000, height: 1000)

PlaygroundPage.current.liveView = viewController

以编程方式将视图添加到StackView中不执行任何操作

1 个答案: