Xamarin在ListView中使用StackLayout可见性形成跨平台问题
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我有一个带有ListView的Xamarin Forms Cross Platform项目，其ViewCell包含一个StackLayout。当用户点击图像时，我隐藏并显示StackLayout。有一个已知的问题，ViewCell没有在ios上正确调整大小，我发现解决方案是在ViewCell上使用ForceUpdateSize方法，以便iOS上的应用程序调整单元格的大小。这是在调整ViewCell大小的方面起作用 - 但是在调用方法之后，我松开了ViewCell底部的三个按钮。按钮位于网格中，所有代码，xaml和屏幕截图都在下面。任何帮助解决这个问题将不胜感激。
页面XAML：
<ViewCell x:Name="vcDetails" >
<StackLayout Orientation="Vertical" HorizontalOptions="Fill" VerticalOptions="Start">
<BoxView x:Name="bvLine" VerticalOptions="Center" BackgroundColor="Black"
HorizontalOptions="FillAndExpand" HeightRequest="4" />
<StackLayout Orientation="Vertical" HorizontalOptions="Fill" VerticalOptions="Start">
<!-- Info Button and title-->
<StackLayout x:Name="slPlaceName" HorizontalOptions="Fill" VerticalOptions="Start" Orientation="Horizontal" Margin="0,0,0,0">
<Image x:Name="btnDropDown" HorizontalOptions="Start" VerticalOptions="Center" Source="circledropdown.png" Margin="0,4,4,0" IsVisible="{Binding ShowDropDown}"/>
<Image x:Name="btnDropUp" HorizontalOptions="Start" VerticalOptions="Center" Source="circledropup.png" Margin="0,4,4,0" IsVisible="{Binding ShowDropUp}"/>
<Label x:Name="lblPlaceName" TextColor="Gray" FontAttributes="Bold" Text="{Binding Title}" FontSize="Medium" Margin="0,0,0,0" VerticalOptions="Center"
HorizontalOptions="FillAndExpand" />
<StackLayout.GestureRecognizers>
<TapGestureRecognizer Tapped="btnDetails_Clicked" CommandParameter="{Binding ID}"/>
</StackLayout.GestureRecognizers>
</StackLayout>
<StackLayout x:Name="slDetails" Orientation="Vertical" HorizontalOptions="Fill" VerticalOptions="StartAndExpand" Margin="8,4,8,4"
IsVisible="{Binding ShowDetails}" BackgroundColor="LightGray">
<BoxView VerticalOptions="Start" HorizontalOptions="Fill" BackgroundColor="DarkCyan" HeightRequest="2" Margin="0,0,0,0" />
<Label x:Name="lblStreetAddress" VerticalOptions="Start" HorizontalOptions="Start" HorizontalTextAlignment="Start"
TextColor="Black" FontSize="Small" Text="{Binding AddressLine1}" />
<Label x:Name="lblCityStateZip" VerticalOptions="Start" HorizontalOptions="Start" HorizontalTextAlignment="Start" TextColor="Black" FontSize="Small"
Text="{Binding CityStateZip}" />
<Label x:Name="lblHours" VerticalOptions="Start" HorizontalOptions="Start" TextColor="Black" FontSize="Small" Text="{Binding Hours}" HorizontalTextAlignment="Center" />
<Grid x:Name="gvDetailButtons" VerticalOptions="CenterAndExpand" HorizontalOptions="FillAndExpand" Margin="8,4,8,4">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="auto" />
<RowDefinition Height="auto" />
</Grid.RowDefinitions>
<StackLayout x:Name="btnGoToInfoPage" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" Orientation="Vertical" Margin="8,0,4,0"
Grid.Column="0" Grid.Row="0" BackgroundColor="DarkGray" Padding="0,2,0,2">
<StackLayout HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" Orientation="Horizontal">
<Image x:Name="btnInfo" HorizontalOptions="Start" VerticalOptions="CenterAndExpand" Source="infosmall.png" Margin="0,0,4,0" />
<Label x:Name="lblbntInfo" Text="{ext:Translate MoreInfo}" TextColor="Black" FontAttributes="Bold"
HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" FontSize="Small"/>
</StackLayout>
<StackLayout.GestureRecognizers>
<TapGestureRecognizer Tapped="btnGoToInfoPage" CommandParameter="{Binding ID}"/>
</StackLayout.GestureRecognizers>
</StackLayout>
<StackLayout x:Name="slGoToEditPage" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" Orientation="Vertical" Margin="4,0,8,0"
Grid.Column="1" Grid.Row="0" BackgroundColor="DarkGray" Padding="0,2,0,2">
<StackLayout HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" Orientation="Horizontal">
<Image x:Name="btnedit" Source="editsmall.png" Margin="8,0,0,0" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand"/>
<Label x:Name="lblbntEdit" Text="{ext:Translate Edit}" TextColor="Black" FontAttributes="Bold"
HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" FontSize="Small"/>
</StackLayout>
<StackLayout.GestureRecognizers>
<TapGestureRecognizer Tapped="btnedit_Tapped" CommandParameter="{Binding ID}"/>
</StackLayout.GestureRecognizers>
</StackLayout>
</Grid>
<BoxView VerticalOptions="Start" HorizontalOptions="Fill" BackgroundColor="DarkCyan" HeightRequest="2" Margin="0,0,0,0"
Grid.ColumnSpan="2" Grid.Column="0" Grid.Row="1"/>
</StackLayout>
<StackLayout x:Name="slRatingandDistance" Orientation="Horizontal" VerticalOptions="Center" HorizontalOptions="StartAndExpand">
<Label x:Name="lblRatingHeader" Text="{ext:Translate RatingText}" TextColor="Black" FontSize="Small" FontAttributes="Bold"
Margin="4,0,0,0" HorizontalOptions="Start" VerticalOptions="Center"/>
<Label x:Name="lblRatingValue" Text="{Binding Rating}" TextColor="Black" FontSize="Small"
HorizontalOptions="Start" VerticalOptions="Center"/>
<Label x:Name="lblDistanceHeader" Text="{ext:Translate DistanceText}" TextColor="Black" FontSize="Small" FontAttributes="Bold"
Margin="4,0,0,0" HorizontalOptions="Start" VerticalOptions="Center"/>
<Label x:Name="lblDistanceValue" Text="{Binding Distance}" TextColor="Black" FontSize="Small"
HorizontalOptions="Start" VerticalOptions="Center" />
</StackLayout>
<Label x:Name="lblAttributes" Text="{Binding AttributesTexts}"
TextColor="Black" FontSize="Small" LineBreakMode="WordWrap" Margin="0,0,0,0" HorizontalOptions="Start"
VerticalOptions="Start"/>
</StackLayout>
<Grid x:Name="gvButtons" VerticalOptions="CenterAndExpand" HorizontalOptions="FillAndExpand" Margin="4,4,4,4">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<StackLayout x:Name="btnRate" Orientation="Horizontal" HorizontalOptions="FillAndExpand" VerticalOptions="CenterAndExpand" BackgroundColor="DarkGray"
Margin="2,0,2,0" Grid.Column="0" Padding="0,2,0,2">
<StackLayout x:Name="slLayoutRate" Orientation="Horizontal" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" >
<Image x:Name="imgRate" Source="smallstar.png" HorizontalOptions="Center" VerticalOptions="Center" Margin="0,0,4,0" />
<Label x:Name="lblRate" HorizontalOptions="Center" VerticalOptions="CenterAndExpand" Text="{ext:Translate Rate}"
TextColor="Black" FontAttributes="Bold" FontSize="Small" Margin="0,0,0,0" />
</StackLayout>
<StackLayout.GestureRecognizers>
<TapGestureRecognizer Tapped="btnRate_Clicked" CommandParameter="{Binding ID}"/>
</StackLayout.GestureRecognizers>
</StackLayout>
<StackLayout x:Name="btnMap" Orientation="Horizontal" HorizontalOptions="FillAndExpand" VerticalOptions="CenterAndExpand" BackgroundColor="DarkGray"
Margin="2,0,2,0" Grid.Column="1" Padding="0,2,0,2">
<StackLayout x:Name="slLayoutMap" Orientation="Horizontal" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" >
<Image x:Name="imgMap" Source="mapblue.png" HorizontalOptions="Center" VerticalOptions="Center" Margin="0,0,4,0" />
<Label x:Name="lblMap" HorizontalOptions="Center" VerticalOptions="Center" Text="{ext:Translate Map}"
TextColor="Black" FontAttributes="Bold" FontSize="Small" Margin="0,0,0,0" />
</StackLayout>
<StackLayout.GestureRecognizers>
<TapGestureRecognizer Tapped="btnMap_Clicked" CommandParameter="{Binding ID}"/>
</StackLayout.GestureRecognizers>
</StackLayout>
<StackLayout x:Name="btnClosed" Orientation="Horizontal" HorizontalOptions="FillAndExpand" VerticalOptions="CenterAndExpand" BackgroundColor="DarkGray"
Margin="2,0,2,0" Grid.Column="2" Padding="0,2,0,2">
<StackLayout x:Name="slLayoutClosed" Orientation="Horizontal" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" >
<Image x:Name="imgClosed" Source="closed.png" HorizontalOptions="CenterAndExpand" VerticalOptions="Center" Margin="0,0,4,0" />
<Label x:Name="lblClosed" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" Text="{ext:Translate Closed}"
TextColor="Black" FontAttributes="Bold" FontSize="Small" Margin="0,0,0,0" />
</StackLayout>
<StackLayout.GestureRecognizers>
<TapGestureRecognizer Tapped="btnClosed_Clicked" CommandParameter="{Binding ID}"/>
</StackLayout.GestureRecognizers>
</StackLayout>
</Grid>
</StackLayout>
</ViewCell>
对隐藏进行编码/显示堆栈布局。
private void btnDetails_Clicked(object sender, EventArgs e)
{
long ll_PlaceID = -1;
try
{
ll_PlaceID = Convert.ToInt64(((TappedEventArgs)e).Parameter);
ViewModelObjects.NearbyPlaces.ShowDetailText(ll_PlaceID);
if (Device.RuntimePlatform == Device.iOS)
{
((ViewCell)((Element)sender).Parent.Parent.Parent).ForceUpdateSize();
}
}
catch (Exception ex)
{
App.ProcessException(ex);
}
}
从视图模型中显示详细信息代码
public void ShowDetailText(long pl_PlaceID)
{
GBSPlaceDetail lobj_Place = null;
try
{
lobj_Place = (GBSPlaceDetail)(from lobj_Work in GBSPlaceDetails
where lobj_Work.ID == pl_PlaceID
select lobj_Work).ToList()[0];
if (lobj_Place != null)
lobj_Place.ShowDetails = !lobj_Place.ShowDetails;
}
catch (Exception ex)
{
App.ProcessException(ex);
}
}
任何建议将不胜感激。
答案
没有人真的回应我的帖子所以我开始寻找其他控件使用。我发现SyncFusion也有一个ListView控件。对于Xamarin Forms ListView控件来说，这似乎是一个非常简单的过程（添加所需的命名空间并使用SyncFusion ListView命名空间为所有控件添加前缀）。在iOS上，当扩展列表项条目的大小时，仍然需要调用额外的代码，但SyncFusion代码似乎比Xamarin代码更清晰，因为在使用SyncFusion ListViewcontrol时问题没有显现。
这是我必须在我的PCL项目中的页面代码中包含的代码。 （lvPlaces是我在XAML中的ListView控件的名称）
if (Device.RuntimePlatform == Device.iOS)
{
lvPlaces.ForceUpdateItemSize();
}
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