我可以在FirebaseMessagingService中启动前例任务吗？

Question

我想通过接收Firebase的通知来开始一个较长的过程（例如上传文件）。我不想启动新的前台服务，但想在同一类中处理上传，如下所示：

public class MyFirebaseMessagingService extends FirebaseMessagingService {

@Override
public void onMessageReceived(RemoteMessage remoteMessage) {
    if (remoteMessage.getNotification() != null) {
        final String title=remoteMessage.getNotification().getTitle();
        final String tag = remoteMessage.getNotification().getTag();
        String body = remoteMessage.getNotification().getBody();

        if (tag.equals("start")) {
            startUpload(title,body);
        }
    }
}


public void startUplaod(String title,String body){
    ShowNotification(title,body);
    // and start upload
}

public void ShowNotification(String title,String text){
    Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
            .setContentTitle(title)
            .setContentText(text)
            .setSmallIcon(R.drawable.ic_launcher_foreground)
            .build();
    startForeground(1, notification);
}
}

当我向正在运行的设备发送通知时，有时我在服务器上收到目标文件，有时却没有！通知不固定，我不确定上传任务是否已完成？我猜想完成任务有时间限制（可能是几秒钟），在此之后，升级失败。

在[[FirebaseMessagingService类中启动长任务是否有任何限制？换句话说，startForeground是否可以强制FirebaseMessagingService长时间启动前台任务？

Answer 1

对于提供了onMessageReceived的所有消息，您的服务应在收到后20秒内处理任何消息（在Android Marshmallow中为10秒）。时间窗口可能会更短，具体取决于调用onMessageReceived之前发生的操作系统延迟。之后，各种操作系统行为（例如Android O的后台执行限制）可能会干扰您完成工作的能力。
• 您可以使用JobIntentService上载任务吗，收到通知后我会制作一个示例下载图像。

  class ImageDownloadPushService : JobIntentService() {
  
  override fun onHandleWork(intent: Intent) {
      val bitmap = downloadImage("url")
      Log.e("ImageDownload", "$bitmap")
  }
  
  private fun downloadImage(address: String?): Bitmap? {
      // Convert string to URL
      val url = getUrlFromString(address)
      // Get input stream
      val inputStream = url?.let { getInputStream(it) } ?: return null
      // Decode bitmap
      // Return bitmap result
      return decodeBitmap(inputStream)
  }
  
  
  private fun getUrlFromString(address: String?): URL? {
      return try {
          URL(address)
      } catch (e1: Throwable) {
          null
      }
  }
  
  private fun getInputStream(url: URL): InputStream? {
      var inputStream: InputStream?
      // Open connection
      val conn: URLConnection
      try {
          conn = url.openConnection()
          conn.connect()
          inputStream = conn.getInputStream()
      } catch (e: IOException) {
          inputStream = null
      }
  
      return inputStream
  }
  
  private fun decodeBitmap(inputStream: InputStream): Bitmap? {
      var bitmap: Bitmap?
      try {
          // Turn response into Bitmap
          bitmap = BitmapFactory.decodeStream(inputStream)
          // Close the input stream
          inputStream.close()
      } catch (e: IOException) {
          bitmap = null
      }
  
      return bitmap
  }
  
  companion object {
      private const val JOB_ID = 101
      fun enqueueWork(context: Context, work: Intent) {
          enqueueWork(context, ImageDownloadPushService::class.java, JOB_ID, work)
      }
  }

  }

• 在onMessageReceived（）

  override fun onMessageReceived(context: Context, remoteMessage: ToastRemoteMessage) {
       ImageDownloadPushService.enqueueWork(context, Intent())
  }