I'm using SnapKit in order to make constraints and am creating views programatically. However, there's one thing I can't grasp.
I want to add a child UIView into the content view of a table view cell and set its height. This already causes a unsatisfiable constraint error.
I've tried also setting (estimated)rowHeight in the table view, but that did not help.
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:[email protected]#24 UIView:0x7fa342409240.top == UITableViewCellContentView:0x7fa342413970.top>",
"<SnapKit.LayoutConstraint:[email protected]#24 UIView:0x7fa342409240.bottom == UITableViewCellContentView:0x7fa342413970.bottom>",
"<SnapKit.LayoutConstraint:[email protected]#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:[email protected]#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.
Cell code:
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")
}
}
You need to reference the bottom constraint and change it's priority to 999 / high but not to required , so remove the edges constraint and make them separately
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)
}