Android - Best way to sync SQLite with MySQL [duplicate]

Question

I'm working on a project containing web app and mobile app which records daily user's data. User are able to delete, update their data and they can use many devices to insert data.
I intend to develop this way:
User enter their data and then insert to SQLite. A service will start periodically (each 5hr or sth) to sync with MySQL using timestamp.
I did search for a sample using service and timestamp on the internet but I found nothing. It would be great if there are a sample or tutorial.
I'm new at Android and I have no idea what is the best way to develop an app like this. Thanks in advance.

----EDIT----
I consider using timestamp or synced. Which is more effective?

Answer 1

you could use volley library by google or any alternative libraries, it depends on how you want to send the data, the best approach is that you use JSON to make your life easier, get the data from sqlite that you like to sync with your backend and send it over JsonObjectRequest using volley, for example your request can look like this

jsonObjectRequest postForm = new JsonObjectRequest(Request.Method.POST, URL, YourJsonData, 
    new Response.Listener<JSONObject>() {
        @Override
        public void onResponse(JSONObject response) {
            // here you can get your response.
        }
    }, 
    new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            // here you can tell there is something went wrong.
        }
    });

u could add a new value which indicates whether the value has been sync or no from your local database. for example, lets say you have a table called student and this table has three columns which are ID, NAME and synced in above code when your response return success update that row synced column with true|false which indicates whether this row synced with your backend or no. and to get the data from your database you should do something like this.

public String getStudents() {
    List<Student> students = new ArrayList<Student>();
    String query = "SELECT * FROM student WHERE synced = 0";
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(query, null);
    if (cursor.moveToFirst()) {
        do {
            Student st = new Student();
            st.setId(cursor.getString(cursor.getColumnIndex(ID)));
            st.setName(cursor.getString(cursor.getColumnIndex(NAME)));
            st.setSynced(cursor.getInt(cursor.getColumnIndex(SYNCED)));
            students.add(st);
        } while (cursor.moveToNext());
    }
    db.close();
    return new Gson().toJson(students);
}

Answer 2

The esieast way AFAIK is to use a lib like http://loopj.com/android-async-http/ or volley lije k0sh says to send data to a PHP script that will manage you mysql data. You'll have to write a php( or java) script in your server to receive your data ( You should write a REST API)

To select your HTTP lib, you should look here:

What is the most robust HTTP library for android?

You should really care about how you are going to sync your datas, because it could drain your battery. Here you will learn how to optimize your updates:

https://developer.android.com/training/efficient-downloads/index.html

Hope it helps!