Java Firebase 云消息。给大家发消息

Question

我想向所有设备发送消息，但我只发送到一台设备，这就是我发送消息的方式:当我在发送消息的方法中删除此消息时，我只能向一个用户发送消息:

json.put("to", tokenId.trim());

当我有这条线时，消息不会发送给任何人，我只向一个用户发送消息。我如何向每个人发送消息？

 static void send_FCM_Notification(String tokenId, String server_key, String message) {


        try {
            URL url = new URL(FCM_URL);
// create connection.
            HttpURLConnection conn;
            conn = (HttpURLConnection) url.openConnection();
            conn.setUseCaches(false);
            conn.setDoInput(true);
            conn.setDoOutput(true);
//set method as POST or GET
            conn.setRequestMethod("POST");
//pass FCM server key
            conn.setRequestProperty("Authorization", "key=" + server_key);
//Specify Message Format
            conn.setRequestProperty("Content-Type", "application/json");
//Create JSON Object & pass value
            JSONObject infoJson = new JSONObject();
            infoJson.put("title", "Wiadomosc z serwera");
            infoJson.put("sound", "default");
            infoJson.put("icon", "ic_launcher");
            infoJson.put("body", message);
            JSONObject json = new JSONObject();
            json.put("to", tokenId.trim());
            json.put("notification", infoJson);
            OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
            wr.write(json.toString());
            wr.flush();
            int status = 0;
            if (null != conn) {
                status = conn.getResponseCode();
            }
            if (status != 0) {
                if (status == 200) {
//SUCCESS message
                    BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
                    System.out.println("Android Notification Response : " + reader.readLine());
                } else if (status == 401) {
//client side error
                    System.out.println("Notification Response : TokenId : " + tokenId + " Error occurred : 401");

                } else if (status == 501) {

//server side error

                    System.out.println("Notification Response : [ errorCode=ServerError ] TokenId : " + tokenId);

                } else if (status == 503) {

//server side error

                    System.out.println("Notification Response : FCM Service is Unavailable  TokenId : " + tokenId);

                }


            }

        } catch (MalformedURLException mlfexception) {

// Prototcal Error

            System.out.println("Error occurred while sending push Notification!.." + mlfexception.getMessage());

        } catch (IOException mlfexception) {

//URL problem

            System.out.println("Reading URL, Error occurred while sending push Notification!.." + mlfexception.getMessage());

        } catch (JSONException jsonexception) {

//Message format error

            System.out.println("Message Format, Error occurred while sending push Notification!.." + jsonexception.getMessage());

        } catch (Exception exception) {

//General Error or exception.

            System.out.println("Error occurred while sending push Notification!.." + exception.getMessage());

        }
    }

Answer 1

Firebase 支持所谓的主题

因此，您可以向某个主题发送消息，订阅该主题的所有设备都会收到推送。

您可以有一个名为 all 的主题，然后将每个设备注册到该主题。

这是您的注册方式

FirebaseMessaging.getInstance().subscribeToTopic("all");

然后您只需向该主题发出通知，所有用户都会收到它。

然后替换这一行

json.put("to", tokenId.trim());

与

json.put("to", "/topics/your-topic-name");

在本例中，您的主题名称是 all