Xamarin collectionview 滚动不流畅

Question

我在 Xamarin 中使用集合视图，我不知道滚动不流畅的原因。我在 android 中实现了编译绑定并增加了垃圾收集器的大小。我想要任何关于如何优化集合视图的建议，或者指出问题所在。

<CollectionView x:DataType="viewmodels:PageViewModel"   ItemsSource="{Binding ItemList}" >                     

 <CollectionView.ItemTemplate>
   <DataTemplate x:DataType="models:Item">
     <StackLayout>
          <BoxView HorizontalOptions="FillAndExpand" HeightRequest="5" Color="Silver"/>
          <Grid RowSpacing="0" ColumnSpacing="0" Padding="15,10">
             <Grid.RowDefinitions>
                 <RowDefinition Height="Auto" />
                 <RowDefinition Height="Auto" />
                 <RowDefinition Height="Auto" />
                 <RowDefinition Height="Auto" />
                 <RowDefinition Height="Auto" />
                 <RowDefinition Height="40" />
             </Grid.RowDefinitions>
             <Grid.ColumnDefinitions>
               <ColumnDefinition Width="Auto"/>
               <ColumnDefinition Width="*"/>
               <ColumnDefinition Width="Auto"/>
             </Grid.ColumnDefinitions>
             <StackLayout Grid.Row="0" Grid.ColumnSpan="2" Grid.Column="0" Orientation="Horizontal">
               <ff:CachedImage Source="Image.jpg" HeightRequest="50" WidthRequest="50" HorizontalOptions="Start">
                 <ff:CachedImage.Transformations>
                   <ffTrans:CircleTransformation />
                 </ff:CachedImage.Transformations>
                </ff:CachedImage>
                <StackLayout HorizontalOptions="FillAndExpand" Padding="10,0,0,0">
                  <Label Text="{Binding Name}" FontSize="Small"/>
                  <Label Text="{Binding Date, StringFormat='{0:dd MMM yyyy}'}"  FontSize="Small"/>
                </StackLayout>
            </StackLayout>

       <ImageButton Grid.Row="0" BackgroundColor="Transparent" Grid.Column="2" IsVisible="True"  Source="Icon.png"  WidthRequest="30"  HorizontalOptions="End">
          <ImageButton.Triggers>
            <DataTrigger TargetType="ImageButton" Binding="{Binding .}" Value="True" >
               <Setter Property="IsVisible" Value="False" />
            </DataTrigger>
            <DataTrigger TargetType="ImageButton" Binding="{Binding .}" Value="False" >
              <Setter Property="IsVisible" Value="False" />
            </DataTrigger>
           </ImageButton.Triggers>
         </ImageButton>
         <ImageButton Grid.Row="0" BackgroundColor="Transparent" Grid.Column="2" IsVisible="False" Source="Icon.png"  WidthRequest="30"  HorizontalOptions="End">
       <ImageButton.Triggers>
         <DataTrigger TargetType="ImageButton" Binding="{Binding .}" Value="True" >
           <Setter Property="IsVisible" Value="True" />
         </DataTrigger>
       </ImageButton.Triggers>
    </ImageButton>
    <ImageButton Grid.Row="0" BackgroundColor="Transparent" Grid.Column="2" IsVisible="False" Source="img.png"   WidthRequest="30"   HorizontalOptions="End">
       <ImageButton.Triggers>
         <DataTrigger TargetType="ImageButton" Binding="{Binding .}" Value="False" >
           <Setter Property="IsVisible" Value="True" />
         </DataTrigger>
       </ImageButton.Triggers>
    </ImageButton>

    <ImageButton Grid.Row="0" BackgroundColor="Transparent" Grid.Column="2" Source="Icon.png"  WidthRequest="20"  HorizontalOptions="Center"/>
       <Label Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="3" Text="{Binding Text}" Margin="0,10"/>
       <mediavideoplayer:VideoPlayer x:Name="mediaelement" Grid.Row="2" Grid.Column="0" Grid.ColumnSpan="3" IsEnabled="{Binding Attachments, Converter={StaticResource VideoVisibilityConverter}}" IsVisible="{Binding Attachments ,Converter={StaticResource VideoVisibilityConverter}}" DisplayControls="False" FillMode="ResizeAspectFill"  HeightRequest="350" AutoPlay="True" Repeat="True">
         <mediavideoplayer:VideoPlayer.Source>
           <MultiBinding Converter="{StaticResource VideoUrlConverter}">
             <Binding Path="Attachments.Path" />
             <Binding Path="Attachments" />
           </MultiBinding>
         </mediavideoplayer:VideoPlayer.Source>
     </mediavideoplayer:VideoPlayer>
     <Image IsVisible="{Binding Attachments, Converter={StaticResource ImageVisibilityConverter}}" Grid.Row="2" Grid.Column="0" Grid.ColumnSpan="3" Aspect="AspectFill" Style="{StaticResource StCommentPicture}">
        <Image.Source>
           <MultiBinding Converter="{StaticResource UrlConverter}">
              <Binding Path="Attachments.path" />
              <Binding Path="Attachments" />
           </MultiBinding>
        </Image.Source>
     </Image>

     <StackLayout Grid.Row="3" Grid.Column="0" >
        <Label Text="&#128077;"  />
        <Label Text="&#x1f60d;"  />
        <Label Text="&#128514;"  />
        <Label x:Name="LikesCount" Grid.Row="5" Grid.Column="1" Text="{Binding likes}" />
     </StackLayout>

     <Label Grid.Row="3" Grid.Column="2" HorizontalOptions="End" Text="{Binding Comments, StringFormat='{0} Comments'}" Margin="0,6"/>
     <BoxView Grid.Row="4" Grid.Column="0" Grid.ColumnSpan="3" VerticalOptions="EndAndExpand" HeightRequest="1" Color="LightGray" Margin ="0,5"/>
     <Frame Grid.Row="5" Grid.Column="0" Grid.ColumnSpan="2" x:Name="likeArea" Opacity="0" Padding="0"  HasShadow="true" OutlineColor="#EEEEEE" CornerRadius="70">
         <Grid x:Name="GridlikeArea" Padding="5,0" BackgroundColor="Transparent"  ColumnDefinitions="*,*,*,*,*" VerticalOptions="CenterAndExpand">
           <Grid.RowDefinitions>
               <RowDefinition Height="35"/>
           </Grid.RowDefinitions>
           <ImageButton x:Uid="Like" BackgroundColor="Transparent" Grid.Row="0" Grid.Column="0" Aspect="AspectFit" Source="Like.png" Clicked="LikeFrame_Clicked" ></ImageButton>
           <ImageButton x:Name="Laugh" BackgroundColor="Transparent" Grid.Row="0" Grid.Column="1"  Aspect="AspectFit" Source="Laugh.png" Clicked="LikeFrame_Clicked"></ImageButton>
           <ImageButton x:Name="Love" BackgroundColor="Transparent" Grid.Row="0" Grid.Column="2"  Aspect="AspectFit" Source="love.png" Clicked="LikeFrame_Clicked"></ImageButton>
           <ImageButton x:Name="Sad" BackgroundColor="Transparent"  Grid.Row="0" Grid.Column="3" Aspect="AspectFit" Source="sad.png" Clicked="LikeFrame_Clicked"></ImageButton>
           <ImageButton x:Name="Hate" BackgroundColor="Transparent" Grid.Row="0" Grid.Column="4" Aspect="AspectFit" Source="angry.png" Clicked="LikeFrame_Clicked"></ImageButton>
      </Grid>
   </Frame>
   <Button x:Name="LikeButton" HeightRequest="40" BackgroundColor="{Binding Reactions,Converter={StaticResource ReactionColorConverter}}"

CornerRadius="50" Grid.Row="5" Grid.Column="0" ImageSource="{Binding Reactions, Converter={StaticResource ReactionImageConverter}}" Text="Like" Clicked= "LikeButton_Clicked" HorizontalOptions="StartAndExpand"/>

                                </Grid>
                            </StackLayout>
                        </DataTemplate>
                    </CollectionView.ItemTemplate>
                    <CollectionView.Footer>
                        <StackLayout HorizontalOptions="CenterAndExpand" Padding="0">
                            <Button  BackgroundColor="Transparent" HorizontalOptions="CenterAndExpand" TextColor="#529dff" FontAttributes="Bold" Text="Load More..." Command="{Binding LoadMoreCommand}" Clicked="loadmorebutton_Clicked"/>
                        </StackLayout>
                    </CollectionView.Footer>
                </CollectionView>

**注意：删除 mediavideoplayer:VideoPlayer 控件不会有任何不同 **

Answer 1

问题已由 nuget Glidex 解决。 glidex.forms 是一个小型库，我们可以通过依赖 Glide 来提高 Xamarin.Forms 在 Android 上的图像性能。请参阅我的 post 主题 here。

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