ios - 编程约束折叠单元格 View

Question

我正在开发一个 UITableViewCell，它以 xib 开头，以编程方式向其添加 View ，并具有动态调整的高度。但是，看起来在添加带有约束的编程 View 时，它与最初应用于 xib 的自动调整大小约束冲突，并导致问题。请看下面:

出队我的细胞:

//Table Delegate/Datasource
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

    var cell:S360SSessionMatchTableCell? = tableView.dequeueReusableCellWithIdentifier(XIBFiles.SESSIONMATCHTABLECELL + String(indexPath.row)) as? S360SSessionMatchTableCell

    if ((cell == nil)){
        tableView.registerNib(UINib(nibName: XIBFiles.SESSIONMATCHTABLECELL, bundle: nil), forCellReuseIdentifier: XIBFiles.SESSIONMATCHTABLECELL + String(indexPath.row))
        cell = tableView.dequeueReusableCellWithIdentifier(XIBFiles.SESSIONMATCHTABLECELL + String(indexPath.row)) as? S360SSessionMatchTableCell
    }

    cell!.setupEvents(sessionMatches[indexPath.row]["sessions"]! as! [[String:String]])

    return cell!
}

自定义 UITableViewCell 中的设置事件方法:

func setupEvents(events:[[String:String]]){

    //Set up start and end times
    self.startTimeLbl.text = events[0]["startTime"]!
    self.endTimeLbl.text = events[events.count - 1]["endTime"]!

    //Set up events
    var pastEventView:S360SScheduledEventView? = nil
    var pastEvent:[String:String]? = nil
    for (index, event) in events.enumerate(){
        var topAnchor:NSLayoutConstraint!

        //Create event view
        let eventView:S360SScheduledEventView = NSBundle.mainBundle().loadNibNamed(XIBFiles.SCHEDULEDEVENTVIEW, owner: self, options: nil)[0] as! S360SScheduledEventView

        //Deal with first view added
        if pastEvent == nil{

            //Top anchor setup for first view
            topAnchor = NSLayoutConstraint(item: eventView, attribute: .Top, relatedBy: .Equal, toItem: toLbl, attribute: .Bottom, multiplier: 1, constant: 10)
        }
        else{

            //Check for a break
            let timeFormatter:NSDateFormatter = NSDateFormatter()
            timeFormatter.dateFormat = "hh:mm a"
            let startTime = timeFormatter.dateFromString(pastEvent!["endTime"]!)
            let endTime = timeFormatter.dateFromString(event["startTime"]!)
            if startTime != endTime {

                //Create break view
                let breakView = NSBundle.mainBundle().loadNibNamed(XIBFiles.SCHEDULEDBREAKVIEW, owner: self, options: nil)[0] as! S360SScheduledBreakView

                //Setup breakview constraints
                let bTopAnchor = NSLayoutConstraint(item: breakView, attribute: .Top, relatedBy: .Equal, toItem: pastEventView, attribute: .Bottom, multiplier: 1, constant: 0)
                let bLeftAnchor = NSLayoutConstraint(item: breakView, attribute: .Leading, relatedBy: .Equal, toItem: self.contentView, attribute: .LeadingMargin, multiplier: 1, constant: 0)
                let bRightAnchor = NSLayoutConstraint(item: breakView, attribute: .Trailing, relatedBy: .Equal, toItem: self.contentView, attribute: .TrailingMargin, multiplier: 1, constant: 0)
                let bHeightAnchor = NSLayoutConstraint(item: breakView, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1, constant: 30)

                //Add break view and constraints
                self.addSubview(breakView)
                self.addConstraints([bTopAnchor, bLeftAnchor, bRightAnchor, bHeightAnchor])

                //Top anchor setup for subsequent view
                topAnchor = NSLayoutConstraint(item: eventView, attribute: .Top, relatedBy: .Equal, toItem: breakView, attribute: .Bottom, multiplier: 1, constant: 0)
            }
            else{

                //Top anchor setup for subsequent views
                topAnchor = NSLayoutConstraint(item: eventView, attribute: .Top, relatedBy: .Equal, toItem: pastEventView, attribute: .Bottom, multiplier: 1, constant: 0)
            }

        }

        //Setup other anchors
        let leftAnchor = NSLayoutConstraint(item: eventView, attribute: .Leading, relatedBy: .Equal, toItem: self.contentView, attribute: .LeadingMargin, multiplier: 1, constant: 0)
        let rightAnchor = NSLayoutConstraint(item: eventView, attribute: .Trailing, relatedBy: .Equal, toItem: self.contentView, attribute: .TrailingMargin, multiplier: 1, constant: 0)
        let heightAnchor = NSLayoutConstraint(item: eventView, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1, constant: 60)

        //Setup event view
        eventView.iconImg.image = Images.get_event_image(event["title"]!)
        eventView.titleLbl.text = event["title"]!
        eventView.courtLbl.text = "court" + event["court"]!
        eventView.timeLbl.text = event["startTime"]! + " to " + event["endTime"]!

        //Add event view and constraints
        self.addSubview(eventView)
        self.addConstraints([topAnchor, leftAnchor, rightAnchor, heightAnchor])

        //Prepare for next iteration
        pastEventView = eventView
        pastEvent = event

        //Set up last cell with bottom bound
        if index == events.count - 1 {
            let bottomAnchor = NSLayoutConstraint(item: eventView, attribute: .Bottom, relatedBy: .Equal, toItem: self.contentView, attribute: .BottomMargin, multiplier: 1, constant: 0)
            self.addConstraint(bottomAnchor)
        }

    }
}

xib 中的约束:

这是我得到的错误(粘贴一次，但每个单元格都会出现):

   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.
2016-07-05 15:13:01.654 Shoot360 Scheduler[32779:642808] 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. 
    (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 
(
    "<NSAutoresizingMaskLayoutConstraint:0x7fedd85d5590 h=--& v=--& V:[UITableViewCellContentView:0x7fedda431120(44)]>",
    "<NSLayoutConstraint:0x7fedda43a7e0 V:[Shoot360_Scheduler.S360SScheduledEventView:0x7fedda438b20(60)]>",
    "<NSLayoutConstraint:0x7fedda436590 UITableViewCellContentView:0x7fedda431120.topMargin == UILabel:0x7fedda4312a0'10:00 AM'.top - 15>",
    "<NSLayoutConstraint:0x7fedda436630 UILabel:0x7fedda431c00'to'.top == UILabel:0x7fedda4312a0'10:00 AM'.top>",
    "<NSLayoutConstraint:0x7fedda433b60 V:[UILabel:0x7fedda431c00'to']-(10)-[Shoot360_Scheduler.S360SScheduledEventView:0x7fedda438b20]>",
    "<NSLayoutConstraint:0x7fedda445910 V:[Shoot360_Scheduler.S360SScheduledEventView:0x7fedda4443f0(60)]>",
    "<NSLayoutConstraint:0x7fedda448310 V:[Shoot360_Scheduler.S360SScheduledEventView:0x7fedda438b20]-(0)-[Shoot360_Scheduler.S360SScheduledEventView:0x7fedda4443f0]>",
    "<NSLayoutConstraint:0x7fedda449a00 V:[Shoot360_Scheduler.S360SScheduledEventView:0x7fedda448540(60)]>",
    "<NSLayoutConstraint:0x7fedda4479e0 V:[Shoot360_Scheduler.S360SScheduledEventView:0x7fedda4443f0]-(0)-[Shoot360_Scheduler.S360SScheduledEventView:0x7fedda448540]>",
    "<NSLayoutConstraint:0x7fedda44a100 Shoot360_Scheduler.S360SScheduledEventView:0x7fedda448540.bottom == UITableViewCellContentView:0x7fedda431120.bottomMargin>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x7fedda436590 UITableViewCellContentView:0x7fedda431120.topMargin == UILabel:0x7fedda4312a0'10:00 AM'.top - 15>

行高设置为动态:

override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()

        //Styling
        showAllBtn.layer.cornerRadius = Numbers.CORNERRADIUS

        sessionsTbl.rowHeight = UITableViewAutomaticDimension
        sessionsTbl.estimatedRowHeight = 500
        sessionsTbl.layer.borderColor = Colors.REALLIGHTGREY.CGColor
        sessionsTbl.layer.borderWidth = Numbers.BORDERREG
        sessionsTbl.layer.cornerRadius = Numbers.CORNERRADIUS
        sessionsTbl.separatorStyle = UITableViewCellSeparatorStyle.None
    }

 func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
        return UITableViewAutomaticDimension
    }

Answer 1

约束

V:[UITableViewCellContentView:0x7fedda431120(44)

表示您的表中的 rowHeight 设置为默认值 44pt 而您希望单元格高度是动态的。您必须将 rowHeight 设置为 UITableViewAutomaticDimension 并设置 estimatedRowHeight。

另请注意，单元格会被重复使用，因此您每次调用 setupEvents 时都必须删除之前添加的所有 View 。

另请注意，您不应从 cellForRow 方法内部调用 tableView.registerNib(...)。注册单元格的好地方是 viewDidLoad。