如何在Xamarin中创建无限滚动

Question

所以我有这个应用程序，我正在尝试创建圆形滚动，例如向下滚动时我会得到：

...-项目4-项目5-项目1-项目2-项目3-项目4-项目5-项目1-项目2-项目3-...

这是我正在尝试的图片

因此滚动将是无止境的，因为将重复相同的项目。有人可以帮我吗？

Answer 1

您可以参考Infinite Scrolling

这是一个简单的示例：

安装Nuget Xamarin.Forms.Extended.InfiniteScrolling

页面的axml：

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
         xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
         xmlns:scroll="clr-namespace:Xamarin.Forms.Extended;assembly=Xamarin.Forms.Extended.InfiniteScrolling"
         x:Class="InfiniteScrollingApp.SimplePage">

    <!-- a normal list view -->
    <ListView  CachingStrategy="RecycleElement" ItemsSource="{Binding Items}">

        <!-- the behavior that will enable infinite scrolling -->
        <ListView.Behaviors>
            <scroll:InfiniteScrollBehavior />
        </ListView.Behaviors>

        <!-- the row definition -->
        <ListView.ItemTemplate>
            <DataTemplate>
                <ViewCell>
                        <Label Text="{Binding Name}" />
                </ViewCell>
            </DataTemplate>
        </ListView.ItemTemplate>


    </ListView>

ViewModel：

public class MyViewModel
{
    public InfiniteScrollCollection<MyData> Items { get; set; }

    public MyViewModel()
    {

        var items = new InfiniteScrollCollection<MyData>();
        MyData data1 = new MyData() { Name = "1" };
        MyData data2 = new MyData() { Name = "2" };
        MyData data3 = new MyData() { Name = "3" };
        MyData data4 = new MyData() { Name = "4" };
        MyData data5 = new MyData() { Name = "5" };
        MyData data6 = new MyData() { Name = "6" };
        MyData data7 = new MyData() { Name = "7" };
        MyData data8 = new MyData() { Name = "8" };
        MyData data9 = new MyData() { Name = "9" };
        MyData data10 = new MyData() { Name = "10" };
        MyData data11 = new MyData() { Name = "11" };
        MyData data12 = new MyData() { Name = "12" };
        items.Add(data1);
        items.Add(data2);
        items.Add(data3);
        items.Add(data4);
        items.Add(data5);
        items.Add(data6);
        items.Add(data7);
        items.Add(data8);
        items.Add(data9);
        items.Add(data10);
        items.Add(data11);

        items.Add(data12);
        Items = items;
        //var dataSource = new MyDataSource();

        Items = new InfiniteScrollCollection<MyData>
        {
            OnLoadMore = async () =>
            {

                return items;
            }
        };
        // load the initial data
        Items.LoadMoreAsync();
    }
}

模型：

public class MyData
{
    public string Name { set; get; }
}

效果如下：