为什么我不能 return 对象数组到 Swift 中的 UIStackView？

Question

import UIKit

class MenuBar: UIView{
    let buttonWidth = 50

    let friendsButton: UIImageView = {
        let imageView = UIImageView()
        imageView.translatesAutoresizingMaskIntoConstraints = false
        imageView.image = #imageLiteral(resourceName: "Friends Button")
        imageView.contentMode = .scaleAspectFill
        imageView.widthAnchor.constraint(equalToConstant: 50)
        imageView.heightAnchor.constraint(equalToConstant: 50)
        return imageView
    }()

创建好友按钮

    let circleButton: UIImageView = {
        let imageView = UIImageView()
        imageView.translatesAutoresizingMaskIntoConstraints = false
        imageView.image = #imageLiteral(resourceName: "Small Circle Button")

        imageView.contentMode = .scaleAspectFill
        imageView.widthAnchor.constraint(equalToConstant: 50)
        imageView.heightAnchor.constraint(equalToConstant: 50)
        return imageView
    }()

创建圆形按钮

    let profileButton: UIImageView = {
        let imageView = UIImageView()
        imageView.translatesAutoresizingMaskIntoConstraints = false
        imageView.image = #imageLiteral(resourceName: "Profile Button")
        imageView.contentMode = .scaleAspectFill
        imageView.widthAnchor.constraint(equalToConstant: 50)
        imageView.heightAnchor.constraint(equalToConstant: 50)
        return imageView
    }()

创建个人资料按钮

    let stackView = UIStackView(arrangedSubviews: [profileButton, circleButton, profileButton])}

最后一行是给我错误的那一行：无法在属性初始值设定项

中使用实例成员 'profileButton

Answer 1

您收到的错误消息的重要部分是第二部分，不幸的是您忽略了它。是property initializer is initialized before self。

在没有属性初始化器模式的情况下重写后的下一个错误将是 Expected declaration。这意味着 code segment 需要在函数内部。例如 viewDidLoad()。

因此，要使其正常工作，您的代码需要修改为类似于以下内容：

import UIKit

class MenuBar: UIView {   
    func createStackView() -> UIStackView {
        let buttonWidth = 50

        let friendsButton = UIImageView()
        friendsButton.translatesAutoresizingMaskIntoConstraints = false
        friendsButton.image = #imageLiteral(resourceName: "Friends Button")
        friendsButton.contentMode = .scaleAspectFill
        friendsButton.widthAnchor.constraint(equalToConstant: 50)
        friendsButton.heightAnchor.constraint(equalToConstant: 50)


        let circleButton = UIImageView()
        circleButton.translatesAutoresizingMaskIntoConstraints = false
        circleButton.image = #imageLiteral(resourceName: "Small Circle Button")

        circleButton.contentMode = .scaleAspectFill
        circleButton.widthAnchor.constraint(equalToConstant: 50)
        circleButton.heightAnchor.constraint(equalToConstant: 50)


        let  profileButton = UIImageView()
        profileButton.translatesAutoresizingMaskIntoConstraints = false
        profileButton.image = #imageLiteral(resourceName: "Profile Button")
        profileButton.contentMode = .scaleAspectFill
        profileButton.widthAnchor.constraint(equalToConstant: 50)
        profileButton.heightAnchor.constraint(equalToConstant: 50)

        let stackView = UIStackView(arrangedSubviews: [profileButton, circleButton, profileButton])
        return stackView
    }
}

为什么我不能 return 对象数组到 Swift 中的 UIStackView？

Why can't I return an array of objects to UIStackView in Swift?

ios

swift

uistackview

swift3