apply plugin:'com.google.gms.google服务'
classpath'com.google。gms:google-services:4.3.3'
添加的依赖项

implementation'com.google.firebase:firebase-auth:19.2.0'
    implementation'com.google.firebase:firebase-core:17.2.2'
    implementation'com.google.firebase:firebase-crash:16.2.1'
    implementation'com.google.firebase:firebase-messaging:20.1.0'
    implementation'com.google.firebase:firebase-analytics:17.2.2'

    implementation'androidx.legacy:legacy-support-v4:1.0.0'
    implementation'com.google.android.gms:play-services-tagmanager:17.0.0'

myfirebaseinstanceidservice.java

public class MyFirebaseInstanceIDService extends FirebaseMessagingService {

    private static final String TAG = "MyFirebaseIIDService";
    public static String fcm_Tocken;

    @Override
    public void onNewToken(@NonNull String token) {
        super.onNewToken(s);

        storeRegIdInPref(token);

        sendRegistrationToServer(token);

        Intent registrationComplete = new Intent(CONSTANTS.REGISTRATION_COMPLETE);
        registrationComplete.putExtra("token", token);
        LocalBroadcastManager.getInstance(this).sendBroadcast(registrationComplete);

        String refreshedToken = FirebaseInstanceId.getInstance().getToken();
        FirebaseMessaging.getInstance().subscribeToTopic("all");
        SharedPreferences.Editor editor1 = getSharedPreferences(CONSTANTS.API_param_DeviceToken, MODE_PRIVATE).edit();
        editor1.putString(CONSTANTS.API_param_DeviceToken, refreshedToken); //Friend
        editor1.apply();
        editor1.commit();
        fcm_Tocken = refreshedToken;
    }

    private void sendRegistrationToServer(final String token) {
        // sending gcm token to server
        Log.e(TAG, "sendRegistrationToServer: " + token);
    }

    private void storeRegIdInPref(String token) {
        SharedPreferences.Editor editor1 = getSharedPreferences(CONSTANTS.API_param_DeviceToken, MODE_PRIVATE).edit();
        editor1.putString(CONSTANTS.API_param_DeviceToken, token); //Friend
        editor1.apply();
        editor1.commit();
    }
}

myfirebasemessagingservice.java文件

public class MyFirebaseMessagingService extends FirebaseMessagingService {

    public static final String NOTIFICATION_CHANNEL_ID = "10001";
    private NotificationManager mNotificationManager;
    private NotificationCompat.Builder notificationBuilder;
    Activity context;
    String title = "", image = "", message = "", flag = "", id = "";
    TaskStackBuilder taskStackBuilder;

    private static final String TAG = MyFirebaseMessagingService.class.getSimpleName();

    public static Bitmap getBitmapFromURL(String src) {
        try {
            URL url = new URL(src);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setDoInput(true);
            connection.connect();
            InputStream input = connection.getInputStream();
            return BitmapFactory.decodeStream(input);
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        super.onMessageReceived(remoteMessage);

        Random random = new Random();
        int m = random.nextInt(9999 - 1000) + 1000;
        if (remoteMessage == null)
            return;
        if (remoteMessage.getNotification() != null) {

            Log.e(TAG, "Notification Body: " + remoteMessage.getNotification().getBody());
            title = remoteMessage.getNotification().getTitle();
            message = remoteMessage.getNotification().getBody();

            sendNotification(title, message, flag, id, String.valueOf(m));
        }
        if (remoteMessage.getData().size() > 0) {
            Log.e(TAG, "Data Payload: " + remoteMessage.getData().toString());

            try {
                title = remoteMessage.getData().get("title");
                image = remoteMessage.getData().get("image");
                message = remoteMessage.getData().get("body");
                flag = remoteMessage.getData().get("flag");
                id = remoteMessage.getData().get("id");
                sendNotification(title, message, flag, id, String.valueOf(m));

            } catch (Exception e) {
                Log.e(TAG, "Exception: " + e.getMessage());
            }
        }
    }

    private void sendNotification(String title, String message, String flag, String id, String m) {

        Intent resultIntent = null;
        PendingIntent resultPendingIntent = null;
        taskStackBuilder = TaskStackBuilder.create(this);
        try {
            if (flag != null && flag.equalsIgnoreCase("friend")) {
                resultIntent = new Intent(this, ShareAndEarnActivity.class);
                resultIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
                resultIntent.putExtra(CONSTANTS.back_flag, CONSTANTS.FLAG_ONE);
                resultIntent.putExtra(CONSTANTS.refer_a_freind, CONSTANTS.FLAG_ONE);
                taskStackBuilder.addParentStack(NavigationActivity.class);
                taskStackBuilder.addNextIntentWithParentStack(resultIntent);
                resultPendingIntent = PendingIntent.getActivity(this, 0, resultIntent, 0);
                resultPendingIntent = taskStackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_ONE_SHOT);
            } else {
                resultIntent = new Intent(this, NavigationActivity.class);
                taskStackBuilder.addParentStack(NavigationActivity.class);
                taskStackBuilder.addNextIntentWithParentStack(resultIntent);
                resultPendingIntent = PendingIntent.getActivity(this, 0, resultIntent, 0);
                resultPendingIntent = taskStackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_ONE_SHOT);
            }
            NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
            Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);

            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {

                NotificationChannel notificationChannel = new NotificationChannel("ID", "Name", NotificationManager.IMPORTANCE_HIGH);
                notificationChannel.enableLights(true);
                notificationChannel.enableVibration(true);
                notificationChannel.setDescription("YupIt Notification");
                notificationManager.createNotificationChannel(notificationChannel);

                notificationBuilder = new NotificationCompat.Builder(this, notificationChannel.getId());
            } else {
                notificationBuilder = new NotificationCompat.Builder(this);
            }

            notificationBuilder.setSmallIcon(R.drawable.yupit_tranparent_icon);
            notificationBuilder.setStyle(new NotificationCompat.BigTextStyle().bigText(message));
            notificationBuilder.setContentTitle(title);
            notificationBuilder.setVibrate(new long[]{1000, 1000, 1000, 1000, 1000});
            notificationBuilder.setContentText(message);
            notificationBuilder.setDefaults(Notification.DEFAULT_VIBRATE | Notification.DEFAULT_SOUND | Notification.DEFAULT_LIGHTS
                    | Notification.FLAG_AUTO_CANCEL);
            notificationBuilder.setColor(getResources().getColor(R.color.darkorange));
            notificationBuilder.setAutoCancel(true);
            notificationBuilder.setSound(defaultSoundUri);
            notificationBuilder.setContentIntent(resultPendingIntent);

            if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                notificationBuilder.setSmallIcon(R.drawable.icon);
            } else {
                notificationBuilder.setSmallIcon(R.drawable.icon);
            }
            Notification note = notificationBuilder.build();
            note.flags = Notification.FLAG_INSISTENT;
            note.flags = Notification.DEFAULT_VIBRATE;
            note.flags = Notification.DEFAULT_SOUND;
            note.flags = Notification.DEFAULT_LIGHTS;
            note.flags = Notification.FLAG_AUTO_CANCEL;
            notificationManager.notify(Integer.parseInt(m), note);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}