MAUI Android应用实现Deep Linking时遭遇ClassNotFoundException

点击ed2k链接选择应用打开时，抛出以下错误：

Java.Lang.RuntimeException: 'Unable to instantiate activity ComponentInfo{com.mycompany.test_maui/com.mycompany.test_maui.test_maui.MainActivity}:
java.lang.ClassNotFoundException: Didn't find class "com.mycompany.test_maui.test_maui.MainActivity" on path:
DexPathList[[zip file "/data/app/com.mycompany.test_maui-xpJaFrKRoLluech0atEfZQ==/base.apk"],
nativeLibraryDirectories=[/data/app/com.mycompany.test_maui-xpJaFrKRoLluech0atEfZQ==/lib/arm64,
/data/app/com.mycompany.test_maui-xpJaFrKRoLluech0atEfZQ==/base.apk!/lib/arm64-v8a, /system/lib64, /hw_product/lib64, /system/product/lib64, /prets/lib64]]

现有代码 #

AndroidManifest.xml #

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.mycompany.test_maui">
  <application android:allowBackup="true" android:icon="@mipmap/appicon" android:supportsRtl="true" android:usesCleartextTraffic="true">
    <activity android:name=".MainActivity" android:exported="true">
      <intent-filter>
        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.DEFAULT" />
        <category android:name="android.intent.category.BROWSABLE" />
        <data android:scheme="ed2k" />
      </intent-filter>
    </activity>
  </application>
  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
  <uses-permission android:name="android.permission.INTERNET" />
</manifest>

MainActivity.cs #

using Android.App;
using Android.Content.PM;
using Android.OS;
using Android.Widget;

namespace test_maui
{
    [Activity(Theme = "@style/Maui.SplashTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation | ConfigChanges.UiMode | ConfigChanges.ScreenLayout | ConfigChanges.SmallestScreenSize | ConfigChanges.Density)]
    public class MainActivity : MauiAppCompatActivity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            // Check if the activity was started from a link
            if (Android.Content.Intent.ActionView.Equals(Intent.Action))
            {
                // Get the link
                var elink = Intent.DataString;

                // Display a message on screen with the link
                Toast.MakeText(this, "ed2k Link: " + elink, ToastLength.Long).Show();
            }
        }
    }
}

解决方案 #

错误根源是AndroidManifest中指定的Activity类名与实际编译生成的类名不匹配：

• AndroidManifest的package为com.mycompany.test_maui，使用.MainActivity会被解析为com.mycompany.test_maui.MainActivity
• 但MainActivity的命名空间是test_maui，实际生成的Java类全名为test_maui.MainActivity

可以通过以下两种方式修复：

方式一：统一命名空间与AndroidManifest的package #

修改MainActivity.cs的命名空间，与AndroidManifest中的package保持一致：

namespace com.mycompany.test_maui // 改为和package相同的命名空间
{
    [Activity(Theme = "@style/Maui.SplashTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation | ConfigChanges.UiMode | ConfigChanges.ScreenLayout | ConfigChanges.SmallestScreenSize | ConfigChanges.Density)]
    public class MainActivity : MauiAppCompatActivity
    {
        // 原有代码不变
    }
}

方式二：在AndroidManifest中指定完整类名 #

修改AndroidManifest.xml中Activity的android:name为完整的类名（包含命名空间）：

<activity android:name="test_maui.MainActivity" android:exported="true">
  <!-- 原有intent-filter不变 -->
</activity>

修复后，点击ed2k链接即可正常启动应用并显示链接提示。

内容的提问来源于stack exchange，提问作者Carlos García