如果app在后台,如何使用fcm从服务器发送数据？

我从服务器发送包含user_id的数据.如果应用程序位于前台,我将在FirebaseMessageService类中获取此userId.但是,当应用程序处于后台时,不会得到它.由于FirebaseMessagingService类仅在应用程序处于前台时才会执行.

那么当应用程序处于后台时,如何获得此ID？

    public class MyFirebaseMessagingService extends FirebaseMessagingService {

    private static final String TAG = "MyFirebaseMsgService";
    private String mUserId;
    private Boolean mUpdateNotification;

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        //Displaying data in log
        //It is optional
        Log.d(TAG, "From: " + remoteMessage.getFrom());
        Log.d(TAG, "Notification Message Body: " + remoteMessage.getNotification().getBody());

        String clickAction = remoteMessage.getNotification().getClickAction();

        mUserId = remoteMessage.getData().get("user_id");

        String title = remoteMessage.getNotification().getTitle();

        //Calling method to generate notification
        sendNotification(remoteMessage.getNotification().getBody(),clickAction,title);
    }

    //This method is only generating push notification
    //It is same as we did in earlier posts
    private void sendNotification(String messageBody,String clickAction,String title) {

        mUpdateNotification = true;

        Intent intent = new Intent(clickAction);

        intent.putExtra("userId",mUserId);
        intent.putExtra("updateNotification",mUpdateNotification);

        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent,
                PendingIntent.FLAG_ONE_SHOT);

        Uri defaultSoundUri= RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
        NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
                .setSmallIcon(R.drawable.ic_launcher)
                .setContentTitle(title)
                .setContentText(messageBody)
                .setAutoCancel(true)
                .setSound(defaultSoundUri)
                .setContentIntent(pendingIntent);

        NotificationManager notificationManager =
                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

        notificationManager.notify(0, notificationBuilder.build());
    }
}

编辑：

我正在使用仍然onMessageReceived的数据有效负载当app在后台时不会被调用.

 public function sendPush($text, $tokens, $apiKey,$user_id)
{

    $notification = array(
        "title" => "User updated profile.",
        "text" => $text,
        'vibrate' => 3,
        "click_action" => "OPEN_ACTIVITY_2",
        'sound' => "default",
        'user_id' => $user_id
    );

    $data = array("user_id" => $user_id);

    $msg = array
    (
        'message' => $text,
        'title' => 'User updated profile.',
        'tickerText' => 'New Message',
    );
    $fields = array
    (
        'to' => $tokens,
        'data' => $data,
        'notification' => $notification
    );

    $headers = array
    (
        'Authorization: key=' . $apiKey,
        'Content-Type: application/json'
    );

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, 'https://android.googleapis.com/gcm/send');
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($fields));

    $result = curl_exec($ch);
    //  echo($result);
    //    return $result;
    curl_close($ch);
}

有人可以帮忙吗？谢谢..

Data: in extras of the intent.

进一步来说：

Handle notification messages in a backgrounded app

When your app is in the background, Android directs notification messages to the system tray. A user tap on the notification opens the app launcher by default.

This includes messages that contain both notification and data payload (and all messages sent from the Notifications console). In these cases, the notification is delivered to the device’s system tray, and the data payload is delivered in the extras of the intent of your launcher Activity.

我认为@ArthurThompson的这个answer解释得非常好：

When you send a notification message with a data payload (notification and data) and the app is in the background you can retrieve the data from the extras of the intent that is launched as a result of the user tapping on the notification.

From the 07002 which launches the MainActivity when the notification is tapped:

if (getIntent().getExtras() != null) {
    for (String key : getIntent().getExtras().keySet()) {
        String value = getIntent().getExtras().getString(key);
        Log.d(TAG, "Key: " + key + " Value: " + value);
    }
}