设置UITableViewCell与UITableViewCell高度相同

Question

我需要设置一个图像作为单元格的背景，所以:

第一次尝试:

• 将UIImageView放入单元格
• 设置约束的顶部、尾部、前导和底部为superView
• 设置imageView内容模式为AspectFit

预期:图像拉伸以适应单元格自动大小，必须与UILabel相同

实际:标签在顶部和一大堆空格，因为单元格是获取图像大小。

第二次尝试:

• remove bottom constraint from try 1
• getself.bounds.size.height
• 设置图像
• 然后设置高度约束。

预期:图像之前,得到细胞高度图像主机,然后这个高度适用于图像。

实际:此时单元格没有任何设置，因此具有默认大小，图像小于实际单元格高度。

很多其他的尝试，但没有结果。

有谁知道如何实现这个吗?

Answer 1

好的-听起来问题是你的标签"垂直拉伸"。

要防止这种情况，请设置内容拥抱优先级:

topLabel.setContentHuggingPriority(.required, for: .vertical)
bottomLabel.setContentHuggingPriority(.required, for: .vertical)

这是一个完整的单元格类:

class AlexCell: UITableViewCell {

let topLabel: UILabel = {
let v = UILabel()
v.numberOfLines = 0
v.font = .systemFont(ofSize: 20.0, weight: .bold)
// don't let label expand vertically
v.setContentHuggingPriority(.required, for: .vertical)
return v
}()
let bottomLabel: UILabel = {
let v = UILabel()
v.numberOfLines = 0
v.font = .italicSystemFont(ofSize: 16.0)
// don't let label expand vertically
v.setContentHuggingPriority(.required, for: .vertical)
return v
}()
let imgView: UIImageView = {
let v = UIImageView()
// we want the image to COMPLETELY FILL the image view
v.contentMode = .scaleToFill
// or
//v.contentMode = .scaleAspectFill
return v
}()

override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
commonInit()
}
required init?(coder: NSCoder) {
super.init(coder: coder)
commonInit()
}
private func commonInit() {

// add image view to contentView
imgView.translatesAutoresizingMaskIntoConstraints = false
contentView.addSubview(imgView)

// add labels to content view
topLabel.translatesAutoresizingMaskIntoConstraints = false
contentView.addSubview(topLabel)
bottomLabel.translatesAutoresizingMaskIntoConstraints = false
contentView.addSubview(bottomLabel)
// we'll use the default layout guide for margins
let g = contentView.layoutMarginsGuide

NSLayoutConstraint.activate([

// image view should fill the entire content view
imgView.topAnchor.constraint(equalTo: contentView.topAnchor),
imgView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
imgView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
imgView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor),
// top label top/leading/trailing to margins guide
topLabel.topAnchor.constraint(equalTo: g.topAnchor),
topLabel.leadingAnchor.constraint(equalTo: g.leadingAnchor),
topLabel.trailingAnchor.constraint(equalTo: g.trailingAnchor),
// bottom label top to top label bottom
bottomLabel.topAnchor.constraint(equalTo: topLabel.bottomAnchor, constant: 8.0),
// leading/trailing to margins guide
bottomLabel.leadingAnchor.constraint(equalTo: g.leadingAnchor),
bottomLabel.trailingAnchor.constraint(equalTo: g.trailingAnchor),

// bottom to margins guide
bottomLabel.bottomAnchor.constraint(equalTo: g.bottomAnchor),

])
}

}