如果更新通知给用户

Question

abc.json

[{"id":1,"title":"1. heading of Tips","description":"welcome to post 1"},{"id":2,"title":"2. heading of Tips","description":"welcome to post 2"},{"id":3,"title":"3. heading of Tips","description":"welcome to post 3"},{"id":4,"title":"4. heading of Tips","description":"welcome to post 4"}]

我是android新手。 我希望我的服务检查服务器上的JSON文件是否已更新。如果更新，它将复制数组的最后一个元素，并通过sendNotification（）方法将它们作为通知传递。

MyService.java

public class MyService extends Service {
    private static final String TAG = "MyService";
    String heading="this is heading";
    String post = "this is post";
    public MyService() {
    }

    @Override
    public IBinder onBind(Intent intent) {

        throw new UnsupportedOperationException("Not yet implemented");
    }


    @Override
    public void onCreate() {
        Toast.makeText(this, "The new Service was Created", Toast.LENGTH_SHORT).show();



        // call the on Message received
        onMessageReceived(heading,post);

    }
   public void onMessageReceived(String remoteMessage, String body) {
        // TODO(developer): Handle FCM messages here.
        // If the application is in the foreground handle both data and notification messages here.
        // Also if you intend on generating your own notifications as a result of a received FCM
        // message, here is where that should be initiated. See sendNotification method below.
        Log.d(TAG, "From: " + remoteMessage);
        Log.d(TAG, "Notification Message Body: " + body);
       sendNotification(remoteMessage,body);
    }
    // [END receive_message]
    /**
     * Create and show a simple notification containing the received FCM message.
     *
     * @param messageBody FCM message body received.
     */
    private void sendNotification(String messageBody, String post) {
        Intent intent = new Intent(this, MainActivity.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0 /* Request code */, intent,
                PendingIntent.FLAG_ONE_SHOT);

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

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

        notificationManager.notify(0 /* ID of notification */, notificationBuilder.build());
    }

    // send notification ends


    @Override
    public void onDestroy() {
        Toast.makeText(this, "Service Destroyed", Toast.LENGTH_LONG).show();

    }

}