ios - Swift iOS - setContentHuggingPriority 优先考虑错误的标签

Question

我有一个带有 4 个标签的单元格：

2 个独立的静态标签和 2 个独立的动态标签。2 个静态标签中的文本始终显示Receipt #，另一个显示Receipt Date。

我设置它的方式是静态标签都具有固定到单元格的 contentView 的leadingAnchor 的前导锚。他们都setContentHuggingPriority设置为High并setContentCompressionResistancePriority设置为Low。他们的 bottomAnchors 附加到每个匹配的动态标签上lastBaseLineAnchor

动态标签都将其尾随锚钉固定到 contentView 的 trailingAnchor。

收据NumberLabel 的leadingAnchor 被固定到receiptDateLabel 的leadingAnchor。

receiveDateLabel 的leadingAnchor 被固定在距离staticReceiptDateLabel 10 点的位置。这个标签应该是灵活的，但它不是。由于receiptNumberLabels 的leadingAnchor 跟随它，它也没有对齐。

如您所见，staticReceiptDateLabel 较长，但应该更短，receiptDateLabel 应该更长。我已经尝试了不同的值组合，setContentHuggingPriority但setContentCompressionResistancePriority无论我不断得到这些结果，我该如何解决这个问题？

contentView.addSubview(receiptNumberLabel) // dynamic
contentView.addSubview(staticReceiptNumberLabel)
contentView.addSubview(receiptDateLabel) // dynamic
contentView.addSubview(staticReceiptDateLabel)

receiptNumberLabel.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 10).isActive = true
receiptNumberLabel.leadingAnchor.constraint(equalTo: receiptDateLabel.leadingAnchor, constant: 0).isActive = true
receiptNumberLabel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -10).isActive = true
receiptNumberLabel.setContentHuggingPriority(.defaultLow, for: .horizontal)
receiptNumberLabel.setContentCompressionResistancePriority(.defaultHigh, for: .horizontal)

staticReceiptNumberLabel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 10).isActive = true
staticReceiptNumberLabel.lastBaselineAnchor.constraint(equalTo: receiptNumberLabel.lastBaselineAnchor).isActive = true
staticReceiptNumberLabel.setContentHuggingPriority(.defaultHigh, for: .horizontal)
staticReceiptNumberLabel.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)

receiptDateLabel.topAnchor.constraint(equalTo: receiptNumberLabel.bottomAnchor, constant: 10).isActive = true
receiptDateLabel.leadingAnchor.constraint(equalTo: staticReceiptDateLabel.trailingAnchor, constant: 10).isActive = true
receiptDateLabel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -10).isActive = true
receiptDateLabel.setContentHuggingPriority(UILayoutPriority.defaultLow, for: .horizontal)
receiptDateLabel.setContentCompressionResistancePriority(.defaultHigh, for: .horizontal)

staticReceiptDateLabel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 10).isActive = true
staticReceiptDateLabel.lastBaselineAnchor.constraint(equalTo: receiptDateLabel.lastBaselineAnchor).isActive = true
staticReceiptDateLabel.setContentHuggingPriority(UILayoutPriority.defaultHigh, for: .horizontal)
staticReceiptDateLabel.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)

更新

在评论中@bsod 建议根本不要使用拥抱/压缩。我最初没有使用它们并且发生了同样的问题，我作为最后的手段切换到它们。这是没有拥抱/压缩的代码。

receiptNumberLabel.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 10).isActive = true
receiptNumberLabel.leadingAnchor.constraint(equalTo: receiptDateLabel.leadingAnchor, constant: 0).isActive = true
receiptNumberLabel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -10).isActive = true

staticReceiptNumberLabel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 10).isActive = true
staticReceiptNumberLabel.lastBaselineAnchor.constraint(equalTo: receiptNumberLabel.lastBaselineAnchor).isActive = true

receiptDateLabel.topAnchor.constraint(equalTo: receiptNumberLabel.bottomAnchor, constant: 10).isActive = true
receiptDateLabel.leadingAnchor.constraint(equalTo: staticReceiptDateLabel.trailingAnchor, constant: 10).isActive = true
receiptDateLabel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -10).isActive = true

staticReceiptDateLabel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 10).isActive = true
staticReceiptDateLabel.lastBaselineAnchor.constraint(equalTo: receiptDateLabel.lastBaselineAnchor).isActive = true

标签： iosswiftconstraintsuilabel

Answer 1

忘记拥抱/压缩 API 并以此为起点。从左上角的标签开始，从左到右，从上到下。请注意，静态日期标签的顶部锚点固定在收据编号值标签的底部，以防它有多行。

staticReceiptNumberLabel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 10).isActive = true
staticReceiptNumberLabel.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 10).isActive = true

receiptNumberLabel.topAnchor.constraint(equalTo: staticReceiptNumberLabel.topAnchor).isActive = true
receiptNumberLabel.leadingAnchor.constraint(equalTo: staticReceiptNumberLabel.trailing, constant: 10).isActive = true
receiptNumberLabel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -10).isActive = true

staticReceiptDateLabel.leadingAnchor.constraint(equalTo: staticReceiptNumberLabel.leadingAnchor).isActive = true
staticReceiptDateLabel.topAnchor.constraint(equalTo: receiptNumberLabel.bottomAnchor).isActive = true

receiptDateLabel.topAnchor.constraint(equalTo: staticReceiptDateLabel.topAnchor).isActive = true
receiptDateLabel.leadingAnchor.constraint(equalTo: staticReceiptDateLabel.trailingAnchor, constant: 10).isActive = true
receiptDateLabel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -10).isActive = true
receiptDateLabel.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -10).isActive = true

您还可能需要将标题标签显式设置numberOfLines为 1，否则 UIKit 可能会截断值标签，即使它numberOfLines是 0。

如果出于某种原因，您甚至不希望静态标签的大小扩大，也许是因为您给了它们背景颜色，那么您可以引入拥抱/压缩 API。如果是这样，静态标签将是：

theStaticLabel.setContentCompressionResistancePriority(.defaultHigh, for: .horizontal)
theStaticLabel.setContentHuggingPriority(.defaultHigh, for: .horizontal)

动态标签将是：

theDynamicLabel.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
theDynamicLabel.setContentHuggingPriority(.defaultLow, for: .horizontal)