我可以在 FirebaseMessagingService 中启动预告任务吗?

Question

我想通过接收来自 Firebase 的通知来启动一个很长的过程(比如上传文件(。我不想启动新的前台服务，但我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，有时不会！通知不粘，我不确定上传任务是否正在完成？我猜完成任务的时间(可能是几秒钟(是有限制的，在那之后，更新失败。

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

Answer 1

• 对于提供 onMessageReceived 的所有消息，您的服务应在收到后 20 秒内处理任何消息(Android Marshmallow 为 10 秒(。时间窗口可能会更短，具体取决于在调用 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或WorkManager上传任务吗，我在收到通知时制作了一个示例下载图像。

  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)
  }
  }
  

  }

• In onMessageReceived((

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