Xamarin Forms Rotating Listview 调整行宽答案

【问题标题】：Xamarin Forms Rotating Listview adjust row widthXamarin Forms Rotating Listview 调整行宽
【发布时间】：2017-03-31 17:46:26
【问题描述】：

在 Xamarin Forms 中，我想实现一个水平列表视图（如下图所示）。通过旋转这是可能的，但我无法更改行宽。是否还有可能让第二个布局从第一个布局开始？提前致谢！

 <ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
         xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
         x:Class="Recipe.Pages.SearchPage"
         Title="Search">
<ContentPage.Content>
<StackLayout Spacing="5" x:Name="layout" Orientation="Vertical" >
  <StackLayout x:Name="layoutButtons" HorizontalOptions="FillAndExpand" Orientation="Horizontal" Spacing="5" BackgroundColor="Red">
    <Button x:Name="btn1" BackgroundColor="White" Image="@drawable/scan" />
    <Button x:Name="btn2" BackgroundColor="White" Image="@drawable/menu" />
    <Button x:Name="btn3" BackgroundColor="White" Image="@drawable/search" />
  </StackLayout>
  <StackLayout x:Name="layoutList" >
    <ListView  x:Name="listView" Rotation="270" RowHeight="75" >
      <ListView.ItemTemplate>
        <DataTemplate>
          <ViewCell>
            <StackLayout BackgroundColor="#eee" Orientation="Vertical" >
              <StackLayout Orientation="Horizontal" >
                <Button BackgroundColor="White" Rotation="90" Image="{Binding Recipe}" />
              </StackLayout>
          </StackLayout>
          </ViewCell>
        </DataTemplate>
      </ListView.ItemTemplate>
    </ListView>
  </StackLayout>
 </StackLayout>
 </ContentPage.Content>
</ContentPage>

编辑我还尝试在列表视图中使用网格。有同样的问题。

 <ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
         xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
         x:Class="Recipe.Pages.SearchPage"
         Title="Search">
<ContentPage.Content>
<StackLayout Spacing="5" x:Name="layout" Orientation="Vertical" >
  <StackLayout x:Name="layoutButtons" HorizontalOptions="FillAndExpand" Orientation="Horizontal" Spacing="5" BackgroundColor="Red">
    <Button x:Name="btn1" BackgroundColor="White" Image="@drawable/scan" />
    <Button x:Name="btn2" BackgroundColor="White" Image="@drawable/menu" />
    <Button x:Name="btn3" BackgroundColor="White" Image="@drawable/search" />
  </StackLayout>
  <StackLayout x:Name="layoutList" >
    <ListView  x:Name="listView" Rotation="270" RowHeight="75" >
      <ListView.ItemTemplate>
        <DataTemplate>
          <ViewCell>
            <Grid>
              <Grid.RowDefinitions>
                <RowDefinition Height="Auto" />
              </Grid.RowDefinitions>
              <Grid.ColumnDefinitions>
                <ColumnDefinition Width="75" />
              </Grid.ColumnDefinitions>
              <Button Grid.Column="0" BackgroundColor="White" Rotation="90" Image="{Binding Recipe}" />
            </Grid>
          </ViewCell>
        </DataTemplate>
      </ListView.ItemTemplate>
    </ListView>
  </StackLayout>
</StackLayout>
</ContentPage.Content>
</ContentPage>

【问题讨论】：

尝试通过HeightRequest 限制ListView 的Height 或将其放入Grid...
@EgorGromadskiy 为此，我尝试将 WidthRequest 设置为 ListView，但这不起作用。
你找到解决办法了吗？
@PravinD 不，我改变了布局

标签： xaml listview xamarin.forms horizontallist

【解决方案1】：

我也遇到了同样的问题。我使用下面的 xaml 代码来管理ListView 的高度和宽度。

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="VCRoom.HorizontalScroll">
  <ContentPage.Content >
    <RelativeLayout>
      <ListView x:Name="TestListView"
                RowHeight="80"
                Rotation="270"
                RelativeLayout.XConstraint="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0.5, Constant=-40}"
                RelativeLayout.YConstraint="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=-0.5, Constant=40}"
                RelativeLayout.WidthConstraint="{ConstraintExpression Type=Constant, Constant=80}"
                RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1}"
                >
      </ListView>
    </RelativeLayout>
  </ContentPage.Content>
</ContentPage>

在XConstraint 和YConstraint 中更改RowHeight 和Constant 以相应地管理水平ListView 的宽度和高度。

仅供参考下面是我用来填充ListView 项目的自定义单元格。我在每个列表项中显示了垂直标签。

<?xml version="1.0" encoding="UTF-8"?>
<ViewCell xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="VCRoom.TestCell">
  <ViewCell.View>

      <StackLayout Orientation="Horizontal" HorizontalOptions="End" VerticalOptions ="Center">
        <Label Rotation="90" Text="{Binding Day}"  TextColor="#000000" HorizontalOptions="StartAndExpand" VerticalOptions="Start"/>
        <Label Rotation="90" Text="{Binding mDate}" TextColor="#000000" HorizontalOptions="StartAndExpand" VerticalOptions="Start"/>
      </StackLayout>

  </ViewCell.View>
</ViewCell>

希望这对未来的用户有所帮助。

【讨论】：

【解决方案2】：

我发现解决此问题的最佳解决方案是使用 Listview 的属性制作一个 CustomScrollView，就像 Fabio Cozzolino 的 tutorial 中所示。

注意他在 cmets 中有一个updated version。

他创建了一个自定义滚动视图：

public class TLScrollView : ScrollView
{   public static readonly BindableProperty ItemsSourceProperty =
        BindableProperty.Create("ItemsSource", typeof(IEnumerable), typeof(CustomScrollView), default(IEnumerable),
                                BindingMode.Default, null, new BindableProperty.BindingPropertyChangedDelegate(HandleBindingPropertyChangedDelegate));

    private static object HandleBindingPropertyChangedDelegate(BindableObject bindable, object value)
    {
        throw new NotImplementedException();
    }

    public IEnumerable ItemsSource
    {
        get { return (IEnumerable)GetValue(ItemsSourceProperty); }
        set { SetValue(ItemsSourceProperty, value); }
    }

    public static readonly BindableProperty ItemTemplateProperty =
        BindableProperty.Create("ItemTemplate", typeof(DataTemplate), typeof(CustomScrollView), default(DataTemplate));

    public DataTemplate ItemTemplate
    {
        get { return (DataTemplate)GetValue(ItemTemplateProperty); }
        set { SetValue(ItemTemplateProperty, value); }
    }

    public event EventHandler<ItemTappedEventArgs> ItemSelected;

    public static readonly BindableProperty SelectedCommandProperty =
        BindableProperty.Create("SelectedCommand", typeof(ICommand), typeof(CustomScrollView), null);

    public ICommand SelectedCommand
    {
        get { return (ICommand)GetValue(SelectedCommandProperty); }
        set { SetValue(SelectedCommandProperty, value); }
    }

    public static readonly BindableProperty SelectedCommandParameterProperty =
        BindableProperty.Create("SelectedCommandParameter", typeof(object), typeof(CustomScrollView), null);

    public object SelectedCommandParameter
    {
        get { return GetValue(SelectedCommandParameterProperty); }
        set { SetValue(SelectedCommandParameterProperty, value); }
    }

    static void HandleBindingPropertyChangedDelegate(BindableObject bindable, object oldValue, object newValue)
    {
        var isOldObservable = oldValue?.GetType().GetTypeInfo().ImplementedInterfaces.Any(i => i == typeof(INotifyCollectionChanged));
        var isNewObservable = newValue?.GetType().GetTypeInfo().ImplementedInterfaces.Any(i => i == typeof(INotifyCollectionChanged));

        var tl = (CustomScrollView)bindable;
        if (isOldObservable.GetValueOrDefault(false))
        {
            ((INotifyCollectionChanged)oldValue).CollectionChanged -= tl.HandleCollectionChanged;
        }

        if (isNewObservable.GetValueOrDefault(false))
        {
            ((INotifyCollectionChanged)newValue).CollectionChanged += tl.HandleCollectionChanged;
        }

        if (oldValue != newValue)
        {
            tl.Render();
        }
    }

    private void HandleCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
    {
        Render();
    }
}

创建了一个渲染滚动视图的方法：

public void Render ()
{  if (ItemTemplate == null || ItemsSource == null)
        {
            Content = null;
            return;
        }

        var layout = new StackLayout();
        layout.Orientation = Orientation == ScrollOrientation.Vertical ? StackOrientation.Vertical : StackOrientation.Horizontal;

        foreach (var item in ItemsSource)
        {
            var command = SelectedCommand ?? new Command((obj) =>
            {
                var args = new ItemTappedEventArgs(ItemsSource, item);
                ItemSelected?.Invoke(this, args);
            });
            var commandParameter = SelectedCommandParameter ?? item;

            var viewCell = ItemTemplate.CreateContent() as ViewCell;
            viewCell.View.BindingContext = item;
            viewCell.View.GestureRecognizers.Add(new TapGestureRecognizer
            {
                Command = command,
                CommandParameter = commandParameter,
                NumberOfTapsRequired = 1
            });

            layout.Children.Add(viewCell.View);
        }

        Content = layout; }

然后，一个customRenderer 到每个平台（这里是iOS）：

[assembly: ExportRenderer(typeof(TLScrollView), typeof(TLScrollViewRenderer))]

namespace TitiusLabs.Forms.iOS.Controls
{  
class CustomScrollViewRenderer : ScrollViewRenderer
{
    protected override void OnElementChanged(VisualElementChangedEventArgs e)
    {
        base.OnElementChanged(e);

        var element = e.NewElement as CustomScrollView;
        element?.Render();
    }
} }

【讨论】：

【解决方案3】：

您可以使用FlowListView 插件在 xamarin 表单上轻松归档水平列表视图。

NuGet - DLToolkit.Forms.Controls.FlowListView

【讨论】：