(안드로이드)채팅 구현하기

• 필요한 기술

1. 리사이클 뷰.

2. google fcm push서버에 http통신.

3. firebase realtimeDB 쿼리문 가저오기. 

4. background 상태 확인.

 

DB구성

• ChatList: 사용자간에 채팅 기록을 저장.

 

• receiver와 sender로 사용자를 구분함.

 

 

• fcmToken: 해당유저의 현재 fcm토큰을 저장.

 

 1. 리사이클 뷰.

 

---

2. google fcm push서버에 http통신.

 

  1.기존

firebase.google.com/docs/cloud-messaging/http-server-ref?hl=ko

Firebase 클라우드 메시징 HTTP 프로토콜

 

Request

• url: https://fcm.googleapis.com/fcm/send
• type: post

Header

{
	"Content-Type:application/json",
	"Authorization:key=YOUR_FCM_SERVER_KEY"
}

Body

{
    "to":"your-send-firebasekey"
    ,"data":{
     "title":"1234",
     "body":"asd",
     "key_1":"1234",
     "key_2":"1234"   
    }
}

• data object 안쪽 데이터 구성은 원하는 데이터로 구성하면 된다.

Response

{
    "multicast_id": 123456781234,
    "success": 1,
    "failure": 0,
    "canonical_ids": 0,
    "results": [
        {
            "message_id": "0:129831yh2-eubsd9fh23093j234"
        }
    ]
}

 

 

 

  2. 새버전

firebase.google.com/docs/cloud-messaging/migrate-v1?hl=ko

이전 HTTP에서 HTTP v1로 이전  |  Firebase

 

firebase.google.com/docs/cloud-messaging/concept-options?hl=ko#customizing_a_message_across_platforms

FCM 메시지 정보  |  Firebase

• 새버전은 google api 라이브러리를 받아서 써야한다.

		<dependency>
	    	 <groupId>com.google.api-client</groupId>
	    	 <artifactId>google-api-client</artifactId>
	    	 <version>1.30.10</version>
	   </dependency>

		<dependency>
		    <groupId>com.google.code.gson</groupId>
		    <artifactId>gson</artifactId>
		    <version>2.8.6</version>
		</dependency>

 

 

• fcm 서버로 부터 인증토큰을 받아온다.

  private static String getAccessToken() throws IOException {
    GoogleCredential googleCredential = GoogleCredential
        .fromStream(new FileInputStream("YOUR_JSON_FILE_LOCATION"))
        .createScoped(Arrays.asList(SCOPES));
    googleCredential.refreshToken();
    return googleCredential.getAccessToken();
  }

 

 

• 받은 토큰을 header key 중 Authorization의 값으로 사용한다.

  private static HttpURLConnection getConnection() throws IOException {
    // [START use_access_token]
    URL url = new URL(BASE_URL + FCM_SEND_ENDPOINT);
    HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
    httpURLConnection.setRequestProperty("Authorization", "Bearer " + getAccessToken());
    httpURLConnection.setRequestProperty("Content-Type", "application/json; UTF-8");
    return httpURLConnection;
    // [END use_access_token]
  }

 

 

• 위에서 setting한 데이터로 통신을 보낸다.

  /**
   * Send request to FCM message using HTTP.
   *
   * @param fcmMessage Body of the HTTP request.
   * @throws IOException
   */
  private static void sendMessage(JsonObject fcmMessage) throws IOException {
    HttpURLConnection connection = getConnection();
    connection.setDoOutput(true);
    DataOutputStream outputStream = new DataOutputStream(connection.getOutputStream());
    outputStream.writeBytes(fcmMessage.toString());
    outputStream.flush();
    outputStream.close();

    int responseCode = connection.getResponseCode();
    if (responseCode == 200) {
      String response = inputstreamToString(connection.getInputStream());
      System.out.println("Message sent to Firebase for delivery, response:");
      System.out.println("responseCode: "+responseCode);
      System.out.println(response);
    } else {
      System.out.println("Unable to send message to Firebase:");
      String response = inputstreamToString(connection.getErrorStream());
      System.out.println("responseCode: "+responseCode);
      System.out.println(response);
    }
  }

 

Request

{
  "message": {
    "notification": {
      "title": "FCM Notification",
      "body": "Notification from FCM"
    },
    "token": "YOUR_DEVICE_FCM_TOKEN"
  }
}

• notification 값은 별도의 FirebaseMessagingService.class 구현없이도 알림이 가능하다.

Response

{ 
	"name": "projects/YOUR_PROJECT_ID/messages/0:1610703319299158%f3fd72f7f3fd72f7"
}

 

---

3. firebase realtimeDB 쿼리문 가저오기. 

 

firebase.google.com/docs/database/android/start?hl=ko

Android에서 설치 및 설정  |  Firebase 실시간 데이터베이스

 

---

4. background 상태 확인.

 

구현

public class CustomApplication extends Application implements Application.ActivityLifecycleCallbacks {

    public static boolean isBackground = true;
    private static int numStarted = 0;

    @Override
    public void onCreate() {
        super.onCreate();
        registerActivityLifecycleCallbacks( this );
    }

    @Override
    public void onActivityCreated(@NonNull Activity activity, @Nullable Bundle bundle) { }
    @Override
    public void onActivityStarted(@NonNull Activity activity) {
        if (numStarted == 0) {
            // app went to foreground
            isBackground = false;
        }
        numStarted++;
    }
    @Override
    public void onActivityResumed(@NonNull Activity activity) { }
    @Override
    public void onActivityPaused(@NonNull Activity activity) { }
    @Override
    public void onActivityStopped(@NonNull Activity activity) {
        numStarted--;
        if (numStarted == 0) {
            // app went to background
            isBackground = true;
        }
    }
    @Override
    public void onActivitySaveInstanceState(@NonNull Activity activity, @NonNull Bundle bundle) { }
    @Override
    public void onActivityDestroyed(@NonNull Activity activity) { }
}

• - isBackground로 구분 가능.