我不确定这是我的问题还是 Xamarin 的问题。在 iPad 上,我的应用程序可以加载包含 ListView 中数据列表的页面。ListView 中的 View Cell 可能会稍微复杂一些。它包含一个配置文件图像,一些较小的图标使用,它们正在使用 FFImageLoading。
在 iPad 上,当我点击第一页的一个单元格以进入包含数据列表的下一页时,它加载非常顺利。在Android上,当我点击一个单元格进入下一页时,点击的检测速度很慢,ListView的加载时间也很慢。
有没有提高性能?我以为是我从 SQLite 加载的数据。但是,在我将 ListView 上的 ItemsSource 注释掉之后,加载时间就很好了。
这是我用来显示单元格的数据模板。
<ViewCell>
<ViewCell.View>
<StackLayout Spacing="0" Padding="0" VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand">
<StackLayout Orientation="Horizontal" Spacing="10" Padding="0" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand">
<StackLayout Orientation="Horizontal" HorizontalOptions="StartAndExpand">
<controls:CircleImage
Style="{StaticResource profileImageStyle}"
Margin="10, 10, 10, 10"
Source="{Binding Source}"
BorderColor="White"
BorderThickness="2"
VerticalOptions="Center"
HorizontalOptions="Center">
<controls:CircleImage.GestureRecognizers>
<TapGestureRecognizer Tapped="OnChildDetailTapped" />
</controls:CircleImage.GestureRecognizers>
</controls:CircleImage>
<StackLayout VerticalOptions="Fill" Spacing="1" Padding="0,20,0,10" HorizontalOptions="StartAndExpand">
<StackLayout.GestureRecognizers>
<TapGestureRecognizer Tapped="OnChildDetailTapped" />
</StackLayout.GestureRecognizers>
<StackLayout
Orientation="Vertical"
VerticalOptions="Center"
HorizontalOptions="StartAndExpand">
<Label x:Name="childName" Text="{Binding DisplayName}" Style="{StaticResource normalFont}"> </Label>
<local:ChildInfoIconsView
Child="{Binding .}"
VerticalOptions="Fill">
</local:ChildInfoIconsView>
<Label
x:Name="childNotes"
Style="{StaticResource footnoteFont}"
Text="{Binding ChildNotes, StringFormat={x:Static local:AppResources.formatNotes}}"
IsVisible="{Binding HasChildNotes}">
</Label>
<Label
x:Name="noPickupReason"
Style="{StaticResource footnoteFont}"
Text="{Binding NoPickupReason, StringFormat={x:Static local:AppResources.formatNoPickupReason}}"
IsVisible="{Binding HasNoPickupReason}">
</Label>
<Label
x:Name="absentReason"
Style="{StaticResource footnoteFont}"
Text="{Binding AbsentReason, StringFormat={x:Static local:AppResources.formatAbsentReason}}"
IsVisible="{Binding HasAbsentReason}">
</Label>
</StackLayout>
</StackLayout>
</StackLayout>
<StackLayout Orientation="Horizontal" VerticalOptions="FillAndExpand" HorizontalOptions="End">
<StackLayout.Padding>
<OnIdiom x:TypeArguments="Thickness">
<OnIdiom.Phone>5, 20, 10, 20</OnIdiom.Phone>
<OnIdiom.Tablet>10, 30, 30, 30</OnIdiom.Tablet>
</OnIdiom>
</StackLayout.Padding>
<Image
Style="{StaticResource listviewButtonStyle}"
IsVisible="{Binding EnabledSigning, Source={x:Reference page}}"
Source="ic_action_yes.png"
VerticalOptions="FillAndExpand"
HorizontalOptions="End">
<Image.GestureRecognizers>
<TapGestureRecognizer Tapped="OnAttend" />
</Image.GestureRecognizers>
<Image.Margin>
<OnIdiom x:TypeArguments="Thickness">
<OnIdiom.Phone>0, 0, 5, 0</OnIdiom.Phone>
<OnIdiom.Tablet>5, 5, 20, 5</OnIdiom.Tablet>
</OnIdiom>
</Image.Margin>
</Image>
<Image
Style="{StaticResource listviewButtonStyle}"
IsVisible="{Binding EnabledSigning, Source={x:Reference page}}"
Source="ic_action_no.png"
VerticalOptions="FillAndExpand"
HorizontalOptions="End">
<Image.GestureRecognizers>
<TapGestureRecognizer Tapped="OnAbsent" />
</Image.GestureRecognizers>
<Image.Margin>
<OnIdiom x:TypeArguments="Thickness">
<OnIdiom.Phone>5, 0, 0, 0</OnIdiom.Phone>
<OnIdiom.Tablet>20, 5, 5, 5</OnIdiom.Tablet>
</OnIdiom>
</Image.Margin>
</Image>
</StackLayout>
</StackLayout>
</StackLayout>
</ViewCell.View>
</ViewCell>