在 UITableView 中使用 UITableViewDiffableDatasource，添加或删除单元格 -> 警告单元格约束

Question

当 Cell 初始化器调用函数时

    private func configureUI() {
        [dateLabel, previewLabel].forEach {
            contentsStackView.addArrangedSubview($0)
        }
        
        [titleLabel, contentsStackView].forEach {
            mainStackView.addArrangedSubview($0)
        }
        
        contentView.addSubview(mainStackView)
    }
    
    private func setUpConstraints() {
        NSLayoutConstraint.activate([
            mainStackView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 10),
            mainStackView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -10),
            mainStackView.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 5),
            mainStackView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -5)
        ])
        
        dateLabel.setContentCompressionResistancePriority(.required, for: .horizontal)
        previewLabel.setContentHuggingPriority(.init(1), for: .horizontal)
    }
    
    private func setUpAccessory() {
        accessoryType = .disclosureIndicator
    }

添加或删除单元格警告日志消息

2023-09-05 19:52:06.961611+0900 Diary[7318:185913] [LayoutConstraints] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. 
    Try this: 
        (1) look at each constraint and try to figure out which you don't expect; 
        (2) find the code that added the unwanted constraint or constraints and fix it. 
(
    "<NSLayoutConstraint:0x600000118050 V:|-(5)-[UIStackView:0x13c70e940]   (active, names: '|':UITableViewCellContentView:0x13c71acd0 )>",
    "<NSLayoutConstraint:0x6000001180a0 UIStackView:0x13c70e940.bottom == UITableViewCellContentView:0x13c71acd0.bottom - 5   (active)>",
    "<NSLayoutConstraint:0x60000011f9d0 'UIView-Encapsulated-Layout-Height' UITableViewCellContentView:0x13c71acd0.height == 0   (active)>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x6000001180a0 UIStackView:0x13c70e940.bottom == UITableViewCellContentView:0x13c71acd0.bottom - 5   (active)>

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKitCore/UIView.h> may also be helpful.

当你滑动TableViewCell时，会出现上述Log warning，而当你Delete并滚动屏幕时，似乎是Cell被重用时出现的警告。

由于TableView第一次暴露的时候没有任何警告，所以我不认为是cell内部的约束问题。我很困惑，因为警告消息被列为与约束相关的问题。

回答转发问题

Answer 1

删除

mainStackView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -5)

相反，创建此约束，为其分配优先级 999，然后激活它。