我正在使用 FlowListView 进行视频矩阵视图（1x1-2x2-3x3 视图）。对于 iOS 应用，UIView 渲染器用于与第三方视频 SDK 集成。这是 FlowListView。
<flv:FlowListView x:Name="VideoFlowList" FlowColumnCount="{Binding ColumnCount}" RowHeight="{Binding RowHeight, Mode=TwoWay}"
SeparatorVisibility="None" HasUnevenRows="false" BackgroundColor="Transparent"
FlowColumnMinWidth="80" FlowTotalRecords="{Binding TotalRecords, Mode=TwoWay}" FlowItemsSource="{Binding Items}">
<flv:FlowListView.FlowColumnTemplate>
<DataTemplate>
<Grid x:Name="VideoGrid" Padding="2" BackgroundColor="{Binding SelectedBorderColour, Mode=TwoWay}" RowSpacing="1" ColumnSpacing="1">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<video:CameraView x:Name="MyCameraView" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" BackgroundColor="Black" />
<Image x:Name="AddIcon" Source="panel_add.png" Grid.Row="0" Grid.Column="0" IsVisible="{Binding CameraNotAssigned}"
HorizontalOptions="Center" VerticalOptions="Center" Aspect="AspectFit" BackgroundColor="Transparent" WidthRequest="50" HeightRequest="50">
<Image.GestureRecognizers>
<TapGestureRecognizer Command="{Binding BindingContext.AddCameraCommand, Source={x:Reference BrowseItemsPage}}"
CommandParameter="{x:Reference VideoGrid}" NumberOfTapsRequired="1" />
</Image.GestureRecognizers>
</Image>
<Label x:Name="Label" HorizontalOptions="Fill" HorizontalTextAlignment="Center" VerticalOptions="End"
BackgroundColor="Silver" Opacity="0.5" Text="{Binding CameraName, Mode=TwoWay}" TextColor="Black"/>
</Grid>
</DataTemplate>
</flv:FlowListView.FlowColumnTemplate>
</flv:FlowListView>
在矩阵视图启动时，它显示 4 个视图（视图模型中的 ColumnCount = 2，ToTalRecords = 4）并且每次都有效。切换到任何其他视图也可以。但偶尔从单个视图切换到 4 个视图时，只有 2 个新元素，而不是覆盖的 OnElementChanged 中的 4 个。如何确保每次都能获得 4 个新元素？
请注意，从 9 个视图切换到 4 个视图时不会发生此问题。
这是 ViewRenderer 的代码。
public class VideoRender : ViewRenderer<CameraView, UIVideoView>
{
private UIVideoView _videoView;
protected override void OnElementChanged(ElementChangedEventArgs<CameraView> e)
{
base.OnElementChanged(e);
if (e.OldElement != null)
{
//Unsubscribe
_videoView.Tapped -= OnVideoViewTapped;
Log.Debug($"OldElement CameraIndex {e.OldElement.CameraIndex}, PlayWndHandle {e.OldElement.PlayWndHandle}");
}
if (e.NewElement != null)
{
//Control is TNativeView, CameraView
if (Control == null)
{
_videoView = new UIVideoView(Element);
SetNativeControl(_videoView);
}
//Element.PlayWndHandle = Handle;
if (_videoView.Subviews.Length > 0)
{
Element.PlayWndHandle = _videoView.Subviews[0].Handle;
}
App.PlayWndHandles.Add(Element.PlayWndHandle);
Log.Debug($"NewElement CameraIndex {Element.CameraIndex}, PlayWndHandle {Element.PlayWndHandle}");
Log.Debug($"App.PlayWndHandles[{App.PlayWndHandles.Count - 1}]: {Element.PlayWndHandle}");
// Subscribe
_videoView.Tapped += OnVideoViewTapped;
}
}
}
I added a subview in the UIView UIVideoView and play the video in the subview. Is the issue related to the way I use the subview?
void Initialize()
{
//place the video in subview
var subView = new UIView();
subView.UserInteractionEnabled = true;
AddSubview(subView);
if (Subviews.Length > 0)
{
Subviews[0].Frame = new CoreGraphics.CGRect(0, 0, 100, 100);
}
}