Flutter 背景为一个信号的颤振

我正在尝试允许我的颤振应用程序在后台处理通知。我将推送通知与onesignal一起使用，当我滑动并关闭应用程序时，它不再调用onReceiveHandler。所以我读到了NotificationExtender服务：

因此，首先我在android>app>main>java>。>NotificationsService.java中创建了一个类，位于MainActivity.java旁边

并将其添加到android>app>main文件夹中的AndroidMainfest.xml中：

<service
   android:name=".YOUR_CLASS_NAME"
   android:permission="android.permission.BIND_JOB_SERVICE"
   android:exported="false">
   <intent-filter>
      <action android:name="com.onesignal.NotificationExtender" />
   </intent-filter>
</service>

显示以下错误：

error: cannot find symbol
 protected boolean onNotificationProcessing(OSNotificationReceivedResult receivedResult) {
                                            ^
  symbol:   class OSNotificationReceivedResult
  location: class OneSignalSilentNotificationHandler
1 error

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:compileDebugJavaWithJavac'.
> Compilation failed; see the compiler error output for details.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 8s
Finished with error: Gradle task assembleDebug failed with exit code 1

---

那么问题出在哪里，或者这是一种错误的做法，我还必须为颤振创建一个方法通道和本机代码，以便在这种情况下进行通信。

在AndroidMainfest.xml中，内部：

<service
    android:name=".OneSignalNotificationExtender"
    android:permission="android.permission.BIND_JOB_SERVICE"
    android:exported="false">
    <intent-filter>
        <action android:name="com.onesignal.NotificationExtender" />
    </intent-filter>
</service>

<service
    android:name=".OneSignalNotificationExtender"
    android:permission="android.permission.BIND_JOB_SERVICE"
    android:exported="false">
    <intent-filter>
        <action android:name="com.onesignal.NotificationExtender" />
    </intent-filter>
</service>

import com.onesignal.OSNotificationPayload;
import com.onesignal.OSNotificationReceivedResult;
import com.onesignal.NotificationExtenderService;

public class OneSignalNotificationExtender extends NotificationExtenderService  {
   @Override
   protected boolean onNotificationProcessing(OSNotificationReceivedResult receivedResult) {
      if (receivedResult != null) {




      } 

      // Returning true tells the OneSignal SDK you have processed the notification and not to display it's own.
      return false;
   }

}