Answers

• PhilRyan AUMember ✭✭

  June 2014

  A temporary fix for me is to force the RowHeight of the given ListView or TableView.
  e.g.
  ListView fred = new ListView { RowHeight = 100,
  but ideally I would like the height of each row to depend on the content. For example, I might have a list of names where some of the names are particularly long (e.g. the classic Monty Python: 'Tarquin Fin-tim-lin-bin-whin-bim-lim-bus-stop-F'tang-F'tang-Olé-Biscuitbarrel', who was standing for election for the Silly Party, which is going to take two lines to display on most phones).

  4
• RichardHeesbeen NLMember ✭

  June 2014

  You can set the property HasUnevenRows to true and then set the height of the cell.

  4
• MartinBooth USMember ✭✭

  June 2014

  Trying to do the same thing, and it doesn't seem to make a difference whether HasUnevenRows is set to true or not.. The rows are all the same height. What's more is it would be great if Xamarin.Forms could expand the height of the cells to accomodate the content for me, rather than making me calculate the height... either way though, I can't get anything to work at the moment!

  0
• MartinBooth USMember ✭✭

  June 2014

  From the looks of things, HasUnevenRows is not implemented for the ListView, but it is for the TableView (I'm looking at IOS).. for the TableView there is a renderer UnEvenTableViewModelRenderer which overrides GetHeightForRow in the UITableViewSource... no such equivalent exists in the ListView from what I can see.

  Unfortunately, it doesn't seem extensible enough to easily add this functionality myself.

  0
• TheRealJasonSmith USXamarin Team Xamurai

  June 2014

  I have opened a bug about this issue. And you are correct about List/TableView being hard to extend. They are far and away the hardest bits of code of any of the platforms, they make all the other controls look super-duper simple. In fact we had one guy pretty much dedicated to making them work xplat for about 3 months.

  I hope as we are now at a point where things mostly work as expected (save for this bug here) we can look into some extensibility.

  3
• MartinBooth USMember ✭✭

  June 2014

  Well, given that I needed a listview with cells of different heights, I decided to break the rules and customize the IOS renderer. I share it here only as a proof of concept given the use of reflection to get at completely undocumented fields!

  public class DynamicRowHeightListViewRenderer : ListViewRenderer
  {
      protected override void OnModelSet(VisualElement view)
      {
          base.OnModelSet(view);
          var table = (UITableView)this.Control;
          table.Source = new ListViewDataSourceWrapper(this.GetFieldValue<UITableViewSource>(typeof(ListViewRenderer), "dataSource"));
      }
  }
  
  public class ListViewDataSourceWrapper : UITableViewSource
  {
      private readonly UITableViewSource underlyingTableSource;
  
      public ListViewDataSourceWrapper(UITableViewSource underlyingTableSource)
      {
          this.underlyingTableSource = underlyingTableSource;
      }
  
      public override UITableViewCell GetCell(UITableView tableView, NSIndexPath indexPath)
      {
          return this.GetCellInternal(tableView, indexPath);
      }
  
      public override int RowsInSection(UITableView tableview, int section)
      {
          return this.underlyingTableSource.RowsInSection(tableview, section);
      }
  
      public override float GetHeightForHeader(UITableView tableView, int section)
      {
          return this.underlyingTableSource.GetHeightForHeader(tableView, section);
      }
  
      public override UIView GetViewForHeader(UITableView tableView, int section)
      {
          return this.underlyingTableSource.GetViewForHeader(tableView, section);
      }
  
      public override int NumberOfSections(UITableView tableView)
      {
          return this.underlyingTableSource.NumberOfSections(tableView);
      }
  
      public override void RowSelected(UITableView tableView, NSIndexPath indexPath)
      {
          this.underlyingTableSource.RowSelected(tableView, indexPath);
      }
  
      public override string[] SectionIndexTitles(UITableView tableView)
      {
          return this.underlyingTableSource.SectionIndexTitles(tableView);
      }
  
      public override string TitleForHeader(UITableView tableView, int section)
      {
          return this.underlyingTableSource.TitleForHeader(tableView, section);
      }
  
      public override float GetHeightForRow(UITableView tableView, NSIndexPath indexPath)
      {
          var uiCell = this.GetCellInternal(tableView, indexPath);
  
          uiCell.SetNeedsLayout();
          uiCell.LayoutIfNeeded();
  
          var viewCell = uiCell.GetPropertyValue<ViewCell>(uiCell.GetType(), "ViewCell");
  
          return (float)viewCell.RenderHeight;
      }
  
      private UITableViewCell GetCellInternal(UITableView tableView, NSIndexPath indexPath)
      {
          return this.underlyingTableSource.GetCell(tableView, indexPath);
      }
  }
  
  public static class PrivateExtensions
  {
      public static T GetFieldValue<T>(this object @this, Type type, string name)
      {
          var field = type.GetField(name, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.GetField);
          return (T)field.GetValue(@this);
      }
  
      public static T GetPropertyValue<T>(this object @this, Type type, string name)
      {
          var property = type.GetProperty(name, BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance | BindingFlags.GetProperty);
          return (T)property.GetValue(@this);
      }
  }
  

  6
• Stefan.de.Vogelaere USMember ✭

  July 2014

  Any news on this bug @JasonASmith or a confirmation on how to fix this? thx.

  0
• TroyWillmot NZMember, University ✭

  July 2014

  Am having the same issue. Are there any plans for Xamarin to update the renderer for iOS to handle this on a ListView?

  0
• RunarOvesenHjerpbakk NOUniversity ✭✭

  July 2014

  Plus one for this!

  0
• EricMaupin USXamarin Team Xamurai

  July 2014

  HasUnevenRows was fixed for ListView on iOS in 1.2.1

  0
• CraigDunn USXamarin Team Xamurai

  July 2014

  I posted a super-simple example over here which links to the Evolve 13 sample Session list and cell.

  0
• AlexFawcett GBMember ✭

  July 2014

  @ermau‌ - has HasUnevenRows been fixed in TableView as well? Doesn't seem to be working for me in 1.2.1.

  thanks

  0
• EricMaupin USXamarin Team Xamurai

  July 2014

  @Al316‌ Can I see how you're using it? It was never (to my knowledge) broken for TableView.

  0
• Matt.Cook USMember ✭✭

  August 2014

  @MartinBooth‌ Thanks for ListView code for allowing editable fields!

  Does anyone know how to make this work for a TableView as well? Simply setting it to be the type of TableView in the reflection call doesn't seem to work, as I am assuming the reason being the source is gotten a different way.

  0
• DanielHalan.1320 SEMember ✭

  January 2015

  +1, any progress on this issue? as there is a bug report on 'HasUnevenRows not working/implemented on iOS' that currently got "Resolved Invalid" status
  https://bugzilla.xamarin.com/show_bug.cgi?id=22535

  0
• rudyryk RUMember ✭✭✭

  February 2015 edited February 2015

  @DanielHalan.6266 HasUnevenRows partially works for me for TableView and for ListView. I mean, I can have list or table with different height rows, all I need is to calculate height first.

  Calculating height could be tricky though and result code is not really nice, but it works and that's better than nothing

  Here's my gist for measuring text size on iOS:
  https://gist.github.com/rudyryk/7b9633e847e727d12de7

  1
• rudyryk RUMember ✭✭✭

  February 2015

  Does anybody know how to "refresh" TableView after setting new height for already displayed cell?

  It seems like setting new height is just ignored.

  2
• DemiVision USMember ✭✭

  March 2015 edited March 2015

  'HasUnevenRows' seems to work correctly for me on iOS. On Android, I have to set the Height of each cell individually. Setting 'RowHeight' on the parent ListView without setting the height within the cell causes bizarre behavior.

  0
• AntonMakarevich.4563 BYMember ✭

  April 2015

  my question is similar to Alexey's. Is it a way to force cell resize dynamically after binding is done? basically I have a listview with custom viewcell which has grid with 2 rows. first row is always visible, the second one should be visible only when item is selected. so height of selected row is not equal to height of other rows. This behavior works perfectly on Android, but on iOS, it seems to ignore resizing of cell's content, so it messed with the content of next cell. my temporary workaround is to hide next cell, but I need a better solution...

  0
• AntonMakarevich.4563 BYMember ✭

  April 2015

  very ugly workaround for my problem.
  1) modify collection with some dummy item
  page.cs:

          Item _ph1 = new Item() { Title = "1", IsVisible = false };
          void ItemTapped(object sender, ItemTappedEventArgs e)
                  {
                      var item = e.Item as Item;      
                      if (item.IsSelected)
                           item.IsSelected = false;
                      else
                      {
                          foreach (var itm in _viewModel.Items)
                              itm.IsSelected = false;
                          item.IsSelected = true;
                      }
               if (Device.OS == TargetPlatform.iOS)
                      {
                          if (_viewModel.Items.Contains(_ph1))
                              _viewModel.Items.Remove(_ph1);
                          else
                             _viewModel.Items.Add(_ph1);
                      }
                      listViewItems.SelectedItem = null;
                  }
  

  2) manually set height of the cell
  mycell.cs:

      protected override void OnBindingContextChanged()
              {
                  base.OnBindingContextChanged();
                  if (Device.OS == TargetPlatform.iOS)
                  {
                      var item = BindingContext as Item;
                      item.PropertyChanged -= item_PropertyChanged;
                      item.PropertyChanged += item_PropertyChanged;
                  }
              }
          void item_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
          {
              if (e.PropertyName == "IsSelected")
              {
                  var item = sender as Item;
                  Height = (item.IsSelected) ? 300 : 100;
              }
          }
  

  0
• HrishiD INMember ✭✭

  May 2015 edited May 2015

  @AntonM Do you have any solution for this I am having same problem.
  @ermau I am working on accordion list View for iOS. It all works fine when I specify ListView Height in XAML.
  But I want cells to adjust according to the content without specifying height to cell.

  1
• AntonMakarevich.4563 BYMember ✭

  May 2015

  @HrishiD I posted my workaround in the prev post, I know it's a little bit stupid, but I didn't find any other solution as it looks like cell high (on ios) is recalculated only when itemssource is updated...

  0
• HrishiD INMember ✭✭

  May 2015 edited May 2015

  @AntonM I too did the same thing. I created accordion list View with ViewCell and Set height of view Cell by calculating length of each element in a view cell.

  I have one question how different screen sizes will be handled for Icons.
  do I need to create png files for 4s 5s and 6s (i.e for iOS I am talking) ?
  do I need to write code to detect screen size and then set Icons and images for that particular screen?
  if any one could answer that will be great.

  1
• DragosPopescu ROMember ✭

  May 2015

  Almost a year later, this annoying bug is still not fixed!!!

  1
• YuriShteinman CAUniversity ✭✭

  July 2015

  Really annoying!

  0
• tush100 INMember ✭✭

  August 2015

  Any solution for dynamic row height. I cant able to see code.

  0
• tusharthakar USMember ✭

  August 2015

  Any solution for dynamic row height . I can't able to see code.

  0
• tusharthakar USMember ✭

  August 2015

  Any

  0
• tusharthakar USMember ✭

  August 2015

  Any

  0
• alex.2418 USMember ✭

  September 2015

  Any

  2
• alex.2418 USMember ✭

  September 2015

  Any solution for dynamic row height. I cant able to see code.

  0
• Chris.3704 USUniversity ✭✭

  November 2015

  Have you tried setting the HasUnevenRows property to true?

  0
• Theos NLBeta ✭✭

  November 2015

  I've tried many solutions too, not working at all.
  My content in my cell is updated when the RefreshControl is finished and then the cell height isn't updated untill I've scrolled that cell out of the screen shortly.
  My content is very dynamic so can't set the height myself.

  So i'm posting the question as well.. Any update on this?

  1
• XamD PKMember ✭

  December 2015

  Any Solution of this problem??

  0
• JohnWilson.4976 AUMember ✭✭

  December 2015

  So this is still a thing on iOS. I've got the same issue as @TimBrand - height of the cell doesn't change until I scroll it out of view and then back in (at which point the height "jumps" to the new size).

  Come on Xamarin peeps. You can make async/awaits for google play services callbacks, but not get iOS to resize a list view item in-place, out-of-the-box?

  Remind me why I'm spending nearly US$2000/year on droid & ios business licenses?

  3
• AlfredoRomero USUniversity ✭✭

  January 2016

  I have exactly same issue, I need to change row height after tap, my rows don't refresh until listview scroll (re-draw) Any help on this??? custom render?? any sample code??
  thanks !

  0
• JohnH GBMember ✭✭✭✭✭

  February 2016 edited February 2016

  I have the same issue, a custom cell that I want to change the height of depending upon user input. As others have said, in iOS setting the cell height after it has been rendered does nothing until the user forces a refresh by scrolling or rotating the device.
  Based on an earlier suggestion I am going to try to add another cell to the table view (Im not using binding for this) and then immediately remove it to see if it triggers an invalidate or refresh or something that will allow the new cell height to be used. That is a complete fudge though, I should be able to call an Invalidate or Refresh or something like that to force a recalc.

  0
• JeroenBoumans.6481 NLMember ✭✭

  March 2016

  This worked for me:

  HasUnevenRows = true, RowHeight = -1,

  9
• Theos NLBeta ✭✭

  April 2016

  @JeroenBoumans.6481 said:
  This worked for me:

  HasUnevenRows = true, RowHeight = -1,

  Are you sure? Because 'RowHeight = -1' didn't change anything for me.

  0
• Whitchurch.6690 USMember ✭✭

  April 2016

  @JeroenBoumans.6481 your solution has actually worked, for me in my listview that was dynamically adding newer items into the list, during the apps execution. It has resized the listview, although at the moment all my images look magnified.

  Thanks for your solution it works, but for the aesthetics of the UI that are messed up.

  0