c# – Xamarin:用于Android和Windows UWP的Xamarin表单中的分组
发布时间:2020-12-15 08:26:53 所属栏目:百科 来源:网络整理
导读:我已经为ios,android和windows平台设计了Xamarin表单的分组列表视图.当我在列表视图中设置GroupShortNameBindingproperty时,垂直索引(跳转列表)会自动出现在IOS中.但跳转列表不会出现在android中.如何使用自定义渲染在android和windows中获得垂直索引的支持.
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我已经为ios,android和windows平台设计了Xamarin表单的分组列表视图.当我在列表视图中设置GroupShortNameBindingproperty时,垂直索引(跳转列表)会自动出现在IOS中.但跳转列表不会出现在android中.如何使用自定义渲染在android和windows中获得垂直索引的支持.如果任何人都可以提供跨平台支持此功能的自定义渲染源.
解决方法
如果你不想要CustomRenders,最简单的方法是使用XAML hack.
您可以将ListView包装在RelativeLayout中,其高度和宽度等于父(内容页面). 对于列表视图,使用height作为父级,宽度为父级的90%. Android的宽度为90%仅适用于iOS,Windows保持为100%,堆栈布局宽度为0%,IsVisible = false. ViewModel: public class JumpListViewModel : INotifyPropertyChanged
{
private ObservableCollection<Item> _allItems;
private List<string> _alphabetList;
public event PropertyChangedEventHandler PropertyChanged;
[NotifyPropertyChangedInvocator]
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null) => PropertyChanged?.Invoke(this,new PropertyChangedEventArgs(propertyName));
public JumpListViewModel()
{
AllItems = new ObservableCollection<Item>(new List<Item> { new Item { MyText = "1" },new Item { MyText = "2" },new Item { MyText = "3" } });
AlphabetList = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray().Select(x => x.ToString()).ToList();
}
public ObservableCollection<Item> AllItems
{
get { return _allItems; }
set
{
_allItems = value;
OnPropertyChanged();
}
}
public List<string> AlphabetList
{
get { return _alphabetList; }
set
{
_alphabetList = value;
OnPropertyChanged();
}
}
}
查看: <RelativeLayout VerticalOptions="FillAndExpand">
<ListView VerticalOptions="FillAndExpand" HasUnevenRows="True" ItemsSource="{Binding AllItems}"
SeparatorColor="Transparent" SeparatorVisibility="None" BackgroundColor="Transparent"
RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent,Property=Height,Factor=1}">
<RelativeLayout.WidthConstraint>
<OnPlatform x:TypeArguments="Constraint" Android="{ConstraintExpression Type=RelativeToParent,Property=Width,Factor=0.9}"
iOS="{ConstraintExpression Type=RelativeToParent,Factor=1}"
WinPhone="{ConstraintExpression Type=RelativeToParent,Factor=1}" />
</RelativeLayout.WidthConstraint>
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout HorizontalOptions="FillAndExpand" BackgroundColor="Silver">
<Label Text="{Binding MyText}" />
<Button Text="button" />
<BoxView HeightRequest="1" Color="Gray" BackgroundColor="Gray" HorizontalOptions="FillAndExpand" />
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<ListView VerticalOptions="FillAndExpand" HasUnevenRows="True" ItemsSource="{Binding AlphabetList}"
SeparatorColor="Transparent" SeparatorVisibility="None" BackgroundColor="Transparent"
RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent,Factor=0.9}"
RelativeLayout.YConstraint="{ConstraintExpression Type=RelativeToParent,Factor=0.05}"
RelativeLayout.XConstraint="{ConstraintExpression Type=RelativeToParent,Factor=0.9}">
<RelativeLayout.WidthConstraint>
<OnPlatform x:TypeArguments="Constraint" Android="{ConstraintExpression Type=RelativeToParent,Factor=0.1}"
iOS="{ConstraintExpression Type=RelativeToParent,Factor=0,Constant=0}"
WinPhone="{ConstraintExpression Type=RelativeToParent,Constant=0}" />
</RelativeLayout.WidthConstraint>
<ListView.IsVisible>
<OnPlatform x:TypeArguments="x:Boolean" WinPhone="False" iOS="False" Android="True" />
</ListView.IsVisible>
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Label Text="{Binding .}" TextColor="Red" FontSize="Micro" />
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</RelativeLayout>
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