ios - UITableViewCell - 无法同时满足约束
问题描述
我正在使用 SnapKit 来进行约束并以编程方式创建视图。然而,有一件事我无法理解。
我想将子 UIView 添加到表格视图单元格的内容视图中并设置其高度。这已经导致不可满足的约束错误。
我也尝试在表格视图中设置(估计的)rowHeight,但这没有帮助。
2018-07-14 19:21:38.785556+0200[20027:748731] [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.
(
"<SnapKit.LayoutConstraint:0x6000000b6500@WeatherCell.swift#24 UIView:0x7fa342409240.top == UITableViewCellContentView:0x7fa342413970.top>",
"<SnapKit.LayoutConstraint:0x6000000b7880@WeatherCell.swift#24 UIView:0x7fa342409240.bottom == UITableViewCellContentView:0x7fa342413970.bottom>",
"<SnapKit.LayoutConstraint:0x6000000b8a80@WeatherCell.swift#26 UIView:0x7fa342409240.height == 145.784842967987>",
"<NSLayoutConstraint:0x604000282210 'UIView-Encapsulated-Layout-Height' UITableViewCellContentView:0x7fa342413970.height == 146 (active)>"
)
Will attempt to recover by breaking constraint
<SnapKit.LayoutConstraint:0x6000000b8a80@WeatherCell.swift#26 UIView:0x7fa342409240.height == 145.784842967987>
Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.
单元格代码:
class WeatherCell: UITableViewCell {
override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
let expandView = UIView()
self.contentView.addSubview(expandView)
expandView.snp.makeConstraints { view in
view.edges.equalToSuperview()
view.height.equalTo(CGFloat(Float(arc4random()) / Float(UINT32_MAX)) * 200)
}
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
解决方案
您需要引用底部约束并将其优先级更改为 999 / high 但不是 required ,因此删除边缘约束并单独制作
let expandView = UIView()
self.contentView.addSubview(expandView)
expandView.snp.makeConstraints { (view) in
view.bottom.equalTo(self.contentView).priority(999) // can also be .priority(.high)
view.top.left.right.equalTo(self.contentView)
view.height.equalTo(CGFloat(Float(arc4random()) / Float(UINT32_MAX)) * 200)
}
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