在 UIButton 内调整图像大小

Question

我一直在尝试获取放置在 UIButton 内的系统图像以缩放比例，但我在网上找到的解决方案似乎都没有。这是我迄今为止尝试过的：

//the cells objects
var acceptButton = UIButton(type: .custom)
var declineButton = UIButton(type: .custom)


override init(frame: CGRect) {
    super.init(frame: frame)
    
    //add the contents and set its autolayout constraints
    setAutoLayoutConstraints()
}

required init?(coder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

//function to set the autolayout constraints for the cell's contents
func setAutoLayoutConstraints() {
    
    //create the stack view which will contain the accept and reject buttons
    let buttonStackView = UIStackView()
    buttonStackView.axis = .horizontal
    buttonStackView.distribution = .fillEqually
    buttonStackView.alignment = .fill
    
    //add the buttons to the stack view
    buttonStackView.addArrangedSubview(acceptButton)
    buttonStackView.addArrangedSubview(declineButton)
    
    //add the button stack view to the cell
    self.addSubview(buttonStackView)
    buttonStackView.translatesAutoresizingMaskIntoConstraints = false
    buttonStackView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
    buttonStackView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
    buttonStackView.leadingAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
    buttonStackView.trailingAnchor.constraint(equalTo: self.trailingAnchor).isActive = true
    
    //add the button images
    let addImage = UIImage(systemName: "checkmark.circle")
    acceptButton.imageView?.contentMode = .scaleAspectFit
    acceptButton.setImage(addImage, for: .normal)
    acceptButton.imageEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
    acceptButton.addTarget(self, action: #selector(addButtonClicked), for: .touchUpInside)
    
    let declineImage = UIImage(systemName: "xmark.octagon")
    declineButton.imageView?.contentMode = .scaleAspectFit
    declineButton.setImage(declineImage, for: .normal)
    declineButton.addTarget(self, action: #selector(declineButtonClicked), for: .touchUpInside)
    
                    
}

这是我得到的：

（“test test”标签是我为左半部分单元格内容添加的，可以忽略）

我尝试了多种解决方案，例如设置边缘插图、设置按钮的内容模式和按钮的图像视图、使用自定义按钮等，但我似乎无法调整图像大小。

注意：当我使用 setBackgroundImage 将图像设置为背景图像时，我可以调整按钮的大小，但无法缩放适合它的纵横比，只能水平和垂直填充它，这不是我想要做的。

感谢任何帮助，谢谢！

Answer 1

这是一个简单的解决方案示例：首先添加您的 labelTest，然后将 stackView 前导锚设置为 labelTest 尾随... 这是我的表格视图：

class YourViewController: UIViewController, UITabBarDelegate, UITableViewDataSource, UITableViewDelegate {


let tableView = UITableView()

override func viewDidLoad() {
    super.viewDidLoad()
    view.backgroundColor = .green
    
    tableView.delegate = self
    tableView.dataSource = self
    tableView.register(myCell.self, forCellReuseIdentifier: "cellId")
    tableView.backgroundColor = .white
    tableView.translatesAutoresizingMaskIntoConstraints = false
    
    view.addSubview(tableView)
    tableView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
    tableView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
    tableView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
    tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return 10
}

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return 50
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "cellId", for: indexPath) as! myCell
    
    return cell
 }
}

现在设置我的单元格，并设置内容视图的约束（这是正确的方法，而不是直接设置单元格）：

class myCell: UITableViewCell {

let labelTest: UILabel = {
    let label = UILabel()
    label.text = "test Label"
    label.backgroundColor = .red
    label.translatesAutoresizingMaskIntoConstraints = false
    
    return label
}()

var acceptButton = UIButton(type: .custom)
var declineButton = UIButton(type: .custom)

override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
    super.init(style: style, reuseIdentifier: reuseIdentifier)
    acceptButton.backgroundColor = .purple
    declineButton.backgroundColor = .brown
    setAutoLayoutConstraints()
}

required init?(coder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

//function to set the autolayout constraints for the cell's contents
func setAutoLayoutConstraints() {
    
    contentView.addSubview(labelTest)
    labelTest.topAnchor.constraint(equalTo: contentView.topAnchor).isActive = true
    labelTest.leadingAnchor.constraint(equalTo: contentView.leadingAnchor).isActive = true
    labelTest.trailingAnchor.constraint(equalTo: contentView.centerXAnchor).isActive = true
    labelTest.bottomAnchor.constraint(equalTo: contentView.bottomAnchor).isActive = true
    
    let buttonStackView = UIStackView(arrangedSubviews: [acceptButton, declineButton])
    buttonStackView.axis = .horizontal
    buttonStackView.distribution = .fillEqually
    buttonStackView.translatesAutoresizingMaskIntoConstraints = false
    
    //add the button stack view to the cell
    contentView.addSubview(buttonStackView)
    buttonStackView.topAnchor.constraint(equalTo: contentView.topAnchor).isActive = true
    buttonStackView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor).isActive = true
    buttonStackView.leadingAnchor.constraint(equalTo: labelTest.trailingAnchor).isActive = true
    buttonStackView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor).isActive = true
    
    //add the buttons images
    let addImage = UIImage(systemName: "checkmark.circle")
    acceptButton.imageView?.contentMode = .scaleAspectFit
    acceptButton.setImage(addImage, for: .normal)
    acceptButton.imageEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
    acceptButton.addTarget(self, action: #selector(addButtonClicked), for: .touchUpInside)
    
    let declineImage = UIImage(systemName: "xmark.octagon")
    declineButton.imageView?.contentMode = .scaleAspectFit
    declineButton.setImage(declineImage, for: .normal)
    declineButton.addTarget(self, action: #selector(declineButtonClicked), for: .touchUpInside)               
 }
}

如果你想在左/右留一些空间，只需在相对约束中添加常量：

labelTest.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 10).isActive = true
buttonStackView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -10).isActive = true

这是结果