我正在使用 ListView 处理 Xamarin.Forms 项目。
ListView 的 XAML 是
<render:CustomListView x:Name="listview" ItemSelected="ItemSelected" ItemTapped="ItemTapped"></render:CustomListView>
C# 是
public void ItemTapped(object sender, ItemTappedEventArgs e)
{
var Selected = e.Item as Classes.NavigationItem;
//Handle clicked
}
((ListView)sender).SelectedItem = null;
}
private void ItemSelected(object sender, SelectedItemChangedEventArgs e)
{
((ListView)sender).SelectedItem = null;
}
我的自定义渲染器是
Android(自定义 ListView ):
public class NavigationListViewAndroid : ListViewRenderer
{
#pragma warning disable CS0618 // Type or member is obsolete
public NavigationListViewAndroid() { }
#pragma warning restore CS0618 // Type or member is obsolete
public NavigationListViewAndroid(Context context) : base(context)
{
}
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.ListView> e)
{
base.OnElementChanged(e);
Control.SetSelector(Android.Resource.Color.DarkerGray);
}
}
iOS(ViewCell):
public class NavigationViewCelliOS : ViewCellRenderer
{
public override UITableViewCell GetCell(Cell item, UITableViewCell reusableCell, UITableView tv)
{
var cell = base.GetCell(item, reusableCell, tv);
cell.SelectionStyle = UITableViewCellSelectionStyle.Gray;
return cell;
}
}
我的问题是:
Android:它选择了该行但一直保持选中状态,直到您单击另一个(对两者),我希望它在您松开时取消选择
iOS:即使按住也不会突出显示灰色
最佳答案
要将背景颜色应用于 ListView 中的选定项目,请按照以下步骤操作:
制作自定义控件:
using Xamarin.Forms;
namespace xamformsdemo.CustomControls
{
public class ExtendedViewCell : ViewCell
{
public static readonly BindableProperty SelectedBackgroundColorProperty =
BindableProperty.Create("SelectedBackgroundColor",
typeof(Color),
typeof(ExtendedViewCell),
Color.Default);
public Color SelectedBackgroundColor
{
get { return (Color)GetValue(SelectedBackgroundColorProperty); }
set { SetValue(SelectedBackgroundColorProperty, value); }
}
}
}
安卓渲染器:
[assembly: ExportRenderer(typeof(ExtendedViewCell), typeof(ExtendedViewCellRenderer))]
namespace xamformsdemo.Droid.CustomRenderers
{
public class ExtendedViewCellRenderer : ViewCellRenderer
{
private Android.Views.View _cellCore;
private Drawable _unselectedBackground;
private bool _selected;
protected override Android.Views.View GetCellCore(Cell item,
Android.Views.View convertView,
ViewGroup parent,
Context context)
{
_cellCore = base.GetCellCore(item, convertView, parent, context);
_selected = false;
_unselectedBackground = _cellCore.Background;
return _cellCore;
}
protected override void OnCellPropertyChanged(object sender, PropertyChangedEventArgs args)
{
base.OnCellPropertyChanged(sender, args);
if (args.PropertyName == "IsSelected")
{
_selected = !_selected;
if (_selected)
{
var extendedViewCell = sender as ExtendedViewCell;
_cellCore.SetBackgroundColor(extendedViewCell.SelectedBackgroundColor.ToAndroid());
}
else
{
_cellCore.SetBackground(_unselectedBackground);
}
}
}
}
}
iOS 渲染器:
[assembly: ExportRenderer(typeof(ExtendedViewCell), typeof(ExtendedViewCellRenderer))]
namespace xamformsdemo.iOS.CustomRenderers
{
public class ExtendedViewCellRenderer : ViewCellRenderer
{
public override UITableViewCell GetCell(Cell item, UITableViewCell reusableCell, UITableView tv)
{
var cell = base.GetCell(item, reusableCell, tv);
var view = item as ExtendedViewCell;
cell.SelectedBackgroundView = new UIView
{
BackgroundColor = view.SelectedBackgroundColor.ToUIColor(),
};
return cell;
}
}
}
在 XAML 中使用:
<ListView.ItemTemplate>
<DataTemplate>
<customControls:ExtendedViewCell SelectedBackgroundColor="Teal">
<ViewCell.View>
<StackLayout HorizontalOptions="FillAndExpand"
VerticalOptions="FillAndExpand" Orientation="Vertical"
Padding="4" Spacing="8">
<Label TextColor="White" Text="{Binding .ItemName}"/>
<Label TextColor="Yellow" Text="{Binding .LastUpdated, StringFormat='Last seen: {0:HH:mm:ss}'}"/>
</StackLayout>
</ViewCell.View>
</customControls:ExtendedViewCell>
</DataTemplate>
</ListView.ItemTemplate>
您可以引用下面的链接来解决问题:https://blog.wislon.io/posts/2017/04/11/xamforms-listview-selected-colour
关于c# - ListView 没有取消选择,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/49685542/