Xamarin AndroidX RecyclerView 适配器

Question

嗨，我是 Xamarin Android 开发的新手，我已经成功地将我的应用程序迁移到 AndroidX，没有任何错误，但是当我添加 RecyclerView Adapter 时，它给了我一堆错误。任何帮助深表感谢。谢谢

重现步骤：

1. 在 Nuget 中添加了 Xamarin AndroidX 包
2. 添加 RecyclerView 适配器

这是我的包裹：

<PackageReference Include="Xamarin.Android.Support.Design" Version="28.0.0.3" />
    <PackageReference Include="Xamarin.Android.Support.Core.Utils" Version="28.0.0.3" />
    <PackageReference Include="Xamarin.Android.Support.CustomTabs" Version="28.0.0.3" />
    <PackageReference Include="Xamarin.AndroidX.Annotation">
      <Version>1.1.0</Version>
    </PackageReference>
    <PackageReference Include="Xamarin.AndroidX.AppCompat">
      <Version>1.1.0</Version>
    </PackageReference>
    <PackageReference Include="Xamarin.AndroidX.Browser">
      <Version>1.2.0</Version>
    </PackageReference>
    <PackageReference Include="Xamarin.AndroidX.CardView">
      <Version>1.0.0</Version>
    </PackageReference>
    <PackageReference Include="Xamarin.AndroidX.Lifecycle.LiveData">
      <Version>2.2.0</Version>
    </PackageReference>
    <PackageReference Include="Xamarin.AndroidX.Media">
      <Version>1.1.0</Version>
    </PackageReference>
    <PackageReference Include="Xamarin.AndroidX.MediaRouter">
      <Version>1.1.0</Version>
    </PackageReference>
    <PackageReference Include="Xamarin.AndroidX.Migration">
      <Version>1.0.2</Version>
    </PackageReference>
    <PackageReference Include="Xamarin.Essentials" Version="1.3.1" />
    <PackageReference Include="Xamarin.Firebase.Auth">
      <Version>60.1142.1</Version>
    </PackageReference>
    <PackageReference Include="Xamarin.Firebase.Common">
      <Version>60.1142.1</Version>
    </PackageReference>
    <PackageReference Include="Xamarin.Firebase.Database">
      <Version>60.1142.1</Version>
    </PackageReference>
    <PackageReference Include="Xamarin.Google.Android.Material">
      <Version>1.0.0</Version>
    </PackageReference>

这是我的错误：

Severity    Code    Description Project File    Line    Suppression State
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 30  Active
Error   CS1503  Argument 2: cannot convert from 'method group' to 'Action<StorelistAdapterClickEventArgs>'  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 30  Active
Error   CS0246  The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 1   Active
Error   CS0246  The type or namespace name 'Android' could not be found (are you missing a using directive or an assembly reference?)   ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 3   Active
Error   CS0246  The type or namespace name 'Android' could not be found (are you missing a using directive or an assembly reference?)   ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 4   Active
Error   CS0246  The type or namespace name 'Android' could not be found (are you missing a using directive or an assembly reference?)   ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 5   Active
Error   CS0246  The type or namespace name 'RecyclerView' could not be found (are you missing a using directive or an assembly reference?)  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 9   Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 11  Active
Error   CS0246  The type or namespace name 'EventHandler<>' could not be found (are you missing a using directive or an assembly reference?)    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 11  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 11  Active
Error   CS0518  Predefined type 'System.Void' is not defined or imported    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 11  Active
Error   CS0518  Predefined type 'System.Void' is not defined or imported    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 11  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 12  Active
Error   CS0246  The type or namespace name 'EventHandler<>' could not be found (are you missing a using directive or an assembly reference?)    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 12  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 12  Active
Error   CS0518  Predefined type 'System.Void' is not defined or imported    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 12  Active
Error   CS0518  Predefined type 'System.Void' is not defined or imported    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 12  Active
Error   CS0518  Predefined type 'System.String' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 13  Active
Error   CS0518  Predefined type 'System.Void' is not defined or imported    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 15  Active
Error   CS0518  Predefined type 'System.String' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 15  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 21  Active
Error   CS0246  The type or namespace name 'RecyclerView' could not be found (are you missing a using directive or an assembly reference?)  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 21  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 21  Active
Error   CS0246  The type or namespace name 'ViewGroup' could not be found (are you missing a using directive or an assembly reference?) ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 21  Active
Error   CS0518  Predefined type 'System.Int32' is not defined or imported   ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 21  Active
Error   CS0518  Predefined type 'System.Void' is not defined or imported    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 35  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 35  Active
Error   CS0246  The type or namespace name 'RecyclerView' could not be found (are you missing a using directive or an assembly reference?)  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 35  Active
Error   CS0518  Predefined type 'System.Int32' is not defined or imported   ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 35  Active
Error   CS0518  Predefined type 'System.Int32' is not defined or imported   ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 44  Active
Error   CS0115  'StorelistAdapter.ItemCount': no suitable method found to override  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 44  Active
Error   CS0518  Predefined type 'System.Void' is not defined or imported    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 46  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 46  Active
Error   CS0518  Predefined type 'System.Void' is not defined or imported    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 47  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 47  Active
Error   CS0246  The type or namespace name 'RecyclerView' could not be found (are you missing a using directive or an assembly reference?)  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 51  Active
Error   CS0518  Predefined type 'System.Void' is not defined or imported    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 56  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 56  Active
Error   CS0246  The type or namespace name 'View' could not be found (are you missing a using directive or an assembly reference?)  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 56  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 56  Active
Error   CS0246  The type or namespace name 'Action<>' could not be found (are you missing a using directive or an assembly reference?)  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 56  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 56  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 57  Active
Error   CS0246  The type or namespace name 'Action<>' could not be found (are you missing a using directive or an assembly reference?)  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 57  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 57  Active
Error   CS0246  The type or namespace name 'EventArgs' could not be found (are you missing a using directive or an assembly reference?) ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 65  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 67  Active
Error   CS0246  The type or namespace name 'View' could not be found (are you missing a using directive or an assembly reference?)  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 67  Active
Error   CS0518  Predefined type 'System.Void' is not defined or imported    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 67  Active
Error   CS0518  Predefined type 'System.Int32' is not defined or imported   ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 68  Active
Error   CS0518  Predefined type 'System.Void' is not defined or imported    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 68  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 25  Active
Error   CS0246  The type or namespace name 'View' could not be found (are you missing a using directive or an assembly reference?)  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 25  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 30  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 30  Active
Error   CS1503  Argument 3: cannot convert from 'method group' to 'Action<StorelistAdapterClickEventArgs>'  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 30  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 40  Active
Error   CS0518  Predefined type 'System.Array' is not defined or imported   ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 44  Active
Error   CS0518  Predefined type 'System.Object' is not defined or imported  ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 44  Active
Error   CS1061  'string[]' does not contain a definition for 'Length' and no accessible extension method 'Length' accepting a first argument of type 'string[]' could be found (are you missing a using directive or an assembly reference?)    ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 44  Active
Error   CS1729  'RecyclerView.ViewHolder' does not contain a constructor that takes 1 arguments ApplicationName C:\Users\SuperUser\source\repos\ApplicationName\ApplicationName\Adapter\StorelistAdapter.cs 57  Active

Answer 1

首先，请确保您已经安装了这些 nuget 包。

请检查以下地方。

1. 打开你的Adapter.cs，注意RecyclerView.Adapter的命名空间，正确的命名空间是AndroidX.RecyclerView.Widget

1. layout.xml 中RecyclerView 的命名空间，在Android X 中，应更改为androidx.recyclerview.widget.RecyclerView，如下代码所示。

<androidx.recyclerview.widget.RecyclerView
    android:layout_width="match_parent"
    android:layout_height="match_parent" 
    android:id="@+id/recyclerView1"/>

1. 请打开你的Activiy.cs，你的包命名空间LinearLayoutManager和RecyclerView是AndroidX.RecyclerView.Widget

这是我运行 Android Q 的应用程序的 GIF。

这是我的演示。

https://github.com/851265601/XAndroidX