在使用自动布局时，在iOS 8上旋转单元格高度会丢失 [英] On rotation cell height gets lost on iOS 8 when using auto layout

问题描述

通常，iOS 8应该能够计算单元格本身的高度。到目前为止这是有效的，但是如果我旋转设备，则单元格会恢复到44点的标准高度。

这是它的样子：

这就是它的作用轮换后看起来像：

一旦旋转，它就会停留在那个布局中。它再也不会计算出真正的高度了。我不知道为什么。我添加了完整的代码。对于约束，请查看 updateConstraints 。代码在C＃中，但您应该能够阅读它。您可以在Objective-C中发布您的课程解决方案。

VC viewDidLoad ：

  public override void ViewDidLoad（）
 {
 base.ViewDidLoad（）; 
 
 this.TableView.Source = new TestSource（this）; 
 this.TableView.RegisterClassForCellReuse（typeof（CustomCell），TestSource.cellIdentifier）; 
 //this.TableView.RowHeight = 83; 
} 
  

我的数据来源：

  public class TestSource：UITableViewSource 
 {
 public static readonly NSString cellIdentifier = new NSString（CustomCell）; 
私有TestTableVC控制器; 
 
 public TestSource（TestTableVC controller）
 {
 this.controller = controller; 
} 
 
公共覆盖int RowsInSection（UITableView tableview，int section）
 {
 return 10; 
} 
 
公共覆盖UITableViewCell GetCell（UITableView tableView，NSIndexPath indexPath）
 {
 CustomCell cell = tableView.DequeueReusableCell（cellIdentifier）as CustomCell; 
 
 cell.UpdateCell（Max Mustermann，m，new DateTime（2014,12,10），1234567890）; 
 
 cell.SetNeedsUpdateConstraints（）; 
 cell.UpdateConstraintsIfNeeded（）; 
 
返回单元格; 
} 
} 
  

我的 CustomCell ：

 公共类CustomCell：UITableViewCell 
 {
 public static readonly NSString cellIdentifier = new的NSString（ CustomCell）; 
 
 private UILabel fullNameLabel，genderLabel，birthdateLabel，iNumberLabel; 
 private bool didSetupConstraints = false; 
 
 public CustomCell（）
 {
 this.CreateView（）; 
} 
 
 public CustomCell（IntPtr handle）：base（handle）
 {
 
 this.CreateView（）; 
} 
 
 public void UpdateCell（string fullName，string gender，DateTime？birthdate，string iNumber）
 {
 fullNameLabel.Text = fullName; 
 genderLabel.Text =性别+：+性别; 
 birthdateLabel.Text =生于+：+ dateOfBirth.ToString（dd.MM.yyyy）; 
 iNumberLabel.Text = iNumber; 
} 
 
 public override void LayoutSubviews（）
 {
 base.LayoutSubviews（）; 
 
 this.ContentView.SetNeedsLayout（）; 
 this.ContentView.LayoutIfNeeded（）; 
} 
 
 public override void UpdateConstraints（）
 {
 if（！didSetupConstraints）{
 NSMutableDictionary viewsDictionary = new NSMutableDictionary（）; 
 viewsDictionary [fullNameLabel] = fullNameLabel; 
 viewsDictionary [genderLabel] = genderLabel; 
 viewsDictionary [birthdateLabel] = birthdateLabel; 
 viewsDictionary [iNumberLabel] = iNumberLabel; 
 
 fullNameLabel.TranslatesAutoresizingMaskIntoConstraints = false; 
 genderLabel.TranslatesAutoresizingMaskIntoConstraints = false; 
 birthdateLabel.TranslatesAutoresizingMaskIntoConstraints = false; 
 iNumberLabel.TranslatesAutoresizingMaskIntoConstraints = false; 
 
 
 //在iOS 7（自动调整掩码）和iOS 8（layoutSubViews）中调整内容视图的大小。 
 //不知道为什么会发生这种情况，但它应该只涉及nibs，如果你使用iOS 8 SDK并且为iOS 7编译。
 // http://stackoverflow.com/questions/24750158 / autoresizing-issue-of-uicollectionviewcell-contentviews-frame-in-storyboard-pro 
 // http://stackoverflow.com/questions/19132908/auto-layout-constraints-issue-on-ios7-in- uitableviewcell 
 // bug？ 
 if（！UIDevice.CurrentDevice.CheckSystemVersion（8,0））{
 //只需要其中一个语句
 this.ContentView.AutoresizingMask = UIViewAutoresizing.FlexibleHeight | UIViewAutoresizing.FlexibleWidth; 
 this.ContentView.Bounds = new RectangleF（0,0,99999,99999）; 
} 
 
 this.ContentView.AddConstraints（NSLayoutConstraint.FromVisualFormat（H：|  -  [fullNameLabel]，（NSLayoutFormatOptions）0，null，viewsDictionary））; 
 this.ContentView.AddConstraints（NSLayoutConstraint.FromVisualFormat（H：|  -  [genderLabel] |，（NSLayoutFormatOptions）0，null，viewsDictionary））; 
 this.ContentView.AddConstraints（NSLayoutConstraint.FromVisualFormat（H：|  -  [birthdateLabel]，（NSLayoutFormatOptions）0，null，viewsDictionary））; 
 this.ContentView.AddConstraints（NSLayoutConstraint.FromVisualFormat（V：|  - （8） -  [fullNameLabel]  - （5） -  [genderLabel]  - （5） -  [birthdateLabel]  - （8） -  |， （NSLayoutFormatOptions）0，null，viewsDictionary））; 
 this.ContentView.AddConstraint（NSLayoutConstraint.Create（iNumberLabel，NSLayoutAttribute.CenterY，NSLayoutRelation.Equal，this.ContentView，NSLayoutAttribute.CenterY，1,0））; 
 this.ContentView.AddConstraints（NSLayoutConstraint.FromVisualFormat（H：[iNumberLabel]  -  |，（NSLayoutFormatOptions）0，null，viewsDictionary））; 
 
 didSetupConstraints = true; 
} 
 
 base.UpdateConstraints（）; 
} 
 
 private void CreateView（）
 {
 fullNameLabel = new UILabel（）{
 Font = UIFont.BoldSystemFontOfSize（17），
 TextColor = UIColor.Black，
 BackgroundColor = UIColor.Clear，
 LineBreakMode = UILineBreakMode.TailTruncation，
 Lines = 0，
 TextAlignment = UITextAlignment.Left 
}; 
 genderLabel = new UILabel（）{
 Font = UIFont.SystemFontOfSize（15），
 TextColor = UIColor.Black，
 BackgroundColor = UIColor.Clear，
 LineBreakMode = UILineBreakMode.TailTruncation，
 Lines = 0，
 TextAlignment = UITextAlignment.Left 
}; 
 birthdateLabel = new UILabel（）{
 Font = UIFont.SystemFontOfSize（15），
 TextColor = UIColor.Black，
 BackgroundColor = UIColor.Clear，
 LineBreakMode = UILineBreakMode.TailTruncation，
 Lines = 0，
 TextAlignment = UITextAlignment.Left 
}; 
 iNumberLabel = new UILabel（）{
 Font = UIFont.SystemFontOfSize（15），
 TextColor = UIColor.Black，
 BackgroundColor = UIColor.Clear，
 LineBreakMode = UILineBreakMode.TailTruncation，
 Lines = 0，
 TextAlignment = UITextAlignment.Right 
}; 
 
 ContentView.AddSubviews（fullNameLabel，genderLabel，birthdateLabel，iNumberLabel）; 
 
} 
 
} 
  

有什么不对我的约束或是另一个iOS 8错误？ BTW：我正在使用Xcode 6.1和iOS 8.1 SDK，并希望支持iOS 7作为iOS 8设备。 iOS 7是另一个故事。

解决方案

在 viewWillTransitionToSize 函数中，设置 self.tableView.estimatedRowHeight =您估计的行高，它似乎能够解决问题，也许这是苹果的一个错误，可以在将来进行改进。 / p>

Normally iOS 8 should be able to calculate the height of a cell itself. This is working so far, but if I rotate the device the cell gets back to its standard height of 44 points.

This is how it should look like:

This is how it does look like after rotation:

Once rotated it stays in that layout. It never calculates the real height anymore. I don't know why. I have added my complete code. For the constraints have a look into updateConstraints. The code is in C# but you should be able to read it. You can post your solution of course in Objective-C.

VC viewDidLoad:

public override void ViewDidLoad ()
{
    base.ViewDidLoad ();

    this.TableView.Source = new TestSource (this);
    this.TableView.RegisterClassForCellReuse (typeof(CustomCell), TestSource.cellIdentifier);
    //this.TableView.RowHeight = 83;
}

My data source:

public class TestSource : UITableViewSource
{
    public static readonly NSString cellIdentifier = new NSString("CustomCell");
    private TestTableVC controller;

    public TestSource (TestTableVC controller)
    {
        this.controller = controller;
    }

    public override int RowsInSection (UITableView tableview, int section)
    {
        return 10;
    }

    public override UITableViewCell GetCell (UITableView tableView, NSIndexPath indexPath)
    {
        CustomCell cell = tableView.DequeueReusableCell (cellIdentifier) as CustomCell;

        cell.UpdateCell ("Max Mustermann", "m", new DateTime (2014, 12, 10), "1234567890");

        cell.SetNeedsUpdateConstraints ();
        cell.UpdateConstraintsIfNeeded ();

        return cell;
    }
}

My CustomCell:

public class CustomCell : UITableViewCell
{
    public static readonly NSString cellIdentifier = new NSString("CustomCell");

    private UILabel fullNameLabel, genderLabel, birthdateLabel, iNumberLabel;
    private bool didSetupConstraints = false;

    public CustomCell ()
    {
        this.CreateView ();
    }

    public CustomCell (IntPtr handle) : base(handle)
    {

        this.CreateView ();
    }

    public void UpdateCell (string fullName, string gender, DateTime? birthdate, string iNumber)
    {
        fullNameLabel.Text = fullName;
        genderLabel.Text = "Gender" + ": " + gender;
        birthdateLabel.Text = "Born on" + ": " + dateOfBirth.ToString ("dd.MM.yyyy");
        iNumberLabel.Text = iNumber;
    }

    public override void LayoutSubviews()
    {
        base.LayoutSubviews();

        this.ContentView.SetNeedsLayout();
        this.ContentView.LayoutIfNeeded();
    }

    public override void UpdateConstraints()
    {
        if (!didSetupConstraints) {
            NSMutableDictionary viewsDictionary = new NSMutableDictionary ();
            viewsDictionary ["fullNameLabel"] = fullNameLabel;
            viewsDictionary ["genderLabel"] = genderLabel;
            viewsDictionary ["birthdateLabel"] = birthdateLabel;
            viewsDictionary ["iNumberLabel"] = iNumberLabel;

            fullNameLabel.TranslatesAutoresizingMaskIntoConstraints = false;
            genderLabel.TranslatesAutoresizingMaskIntoConstraints = false;
            birthdateLabel.TranslatesAutoresizingMaskIntoConstraints = false;
            iNumberLabel.TranslatesAutoresizingMaskIntoConstraints = false;


            // Sizing of content view is differently in iOS 7 (autoresizing mask) and iOS 8 (layoutSubViews).
            // Don't know why this occurs but it should only concern nibs and if you are using iOS 8 SDK and compile for iOS 7.
            // http://stackoverflow.com/questions/24750158/autoresizing-issue-of-uicollectionviewcell-contentviews-frame-in-storyboard-pro
            // http://stackoverflow.com/questions/19132908/auto-layout-constraints-issue-on-ios7-in-uitableviewcell
            // bug?
            if (!UIDevice.CurrentDevice.CheckSystemVersion (8, 0)) {
                // only one of these statements is needed
                this.ContentView.AutoresizingMask = UIViewAutoresizing.FlexibleHeight | UIViewAutoresizing.FlexibleWidth;
                this.ContentView.Bounds = new RectangleF (0, 0, 99999, 99999);
            }

            this.ContentView.AddConstraints (NSLayoutConstraint.FromVisualFormat ("H:|-[fullNameLabel]", (NSLayoutFormatOptions)0, null, viewsDictionary));
            this.ContentView.AddConstraints (NSLayoutConstraint.FromVisualFormat ("H:|-[genderLabel]|", (NSLayoutFormatOptions)0, null, viewsDictionary));
            this.ContentView.AddConstraints (NSLayoutConstraint.FromVisualFormat ("H:|-[birthdateLabel]", (NSLayoutFormatOptions)0, null, viewsDictionary));
            this.ContentView.AddConstraints (NSLayoutConstraint.FromVisualFormat ("V:|-(8)-[fullNameLabel]-(5)-[genderLabel]-(5)-[birthdateLabel]-(8)-|", (NSLayoutFormatOptions)0, null, viewsDictionary));
            this.ContentView.AddConstraint (NSLayoutConstraint.Create (iNumberLabel, NSLayoutAttribute.CenterY, NSLayoutRelation.Equal, this.ContentView, NSLayoutAttribute.CenterY, 1, 0));
            this.ContentView.AddConstraints (NSLayoutConstraint.FromVisualFormat ("H:[iNumberLabel]-|", (NSLayoutFormatOptions)0, null, viewsDictionary));

            didSetupConstraints = true;
        }

        base.UpdateConstraints ();
    }

    private void CreateView()
    {
        fullNameLabel = new UILabel () {
            Font = UIFont.BoldSystemFontOfSize(17),
            TextColor = UIColor.Black,
            BackgroundColor = UIColor.Clear,
            LineBreakMode = UILineBreakMode.TailTruncation,
            Lines = 0,
            TextAlignment = UITextAlignment.Left
        };
        genderLabel = new UILabel () {
            Font = UIFont.SystemFontOfSize(15),
            TextColor = UIColor.Black,
            BackgroundColor = UIColor.Clear,
            LineBreakMode = UILineBreakMode.TailTruncation,
            Lines = 0,
            TextAlignment = UITextAlignment.Left
        };
        birthdateLabel = new UILabel () {
            Font = UIFont.SystemFontOfSize(15),
            TextColor = UIColor.Black,
            BackgroundColor = UIColor.Clear,
            LineBreakMode = UILineBreakMode.TailTruncation,
            Lines = 0,
            TextAlignment = UITextAlignment.Left
        };
        iNumberLabel = new UILabel () {
            Font = UIFont.SystemFontOfSize(15),
            TextColor = UIColor.Black,
            BackgroundColor = UIColor.Clear,
            LineBreakMode = UILineBreakMode.TailTruncation,
            Lines = 0,
            TextAlignment = UITextAlignment.Right
        };

        ContentView.AddSubviews (fullNameLabel, genderLabel, birthdateLabel, iNumberLabel);

    }

}

Is something wrong with my constraints or is this another iOS 8 bug? BTW: I'm using Xcode 6.1 with the iOS 8.1 SDK and want to support iOS 7 as iOS 8 devices. iOS 7 is another story.

解决方案

In viewWillTransitionToSize function, set self.tableView.estimatedRowHeight = your estimated row height, it seems to be able to fix the problem, and perhaps it is a bug from apple which can be improved in the future.

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