How to get current date and store it to sqlite. After that plot it in graph in x-axis?

Question

I want to get the current date and store it inside SQLite. After that, I want to use it in my graph.

Here is my code for storing data:

private View.OnClickListener onCalculate = new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        double weight = Double.parseDouble(Weight.getText().toString());
        
        String date = new SimpleDateFormat("dd/MM/yyyy", Locale.getDefault()).format(new Date());

        helper.insert(weight, date);

        finish();
    }
};

And here is my SQLite Helper:

public class Helper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "bmi.db";
private static final int SCHEMA_VERSION = 1;

public BMIHelper(Context context) {
    super(context, DATABASE_NAME, null, SCHEMA_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL("CREATE TABLE bmi_table ( _id INTEGER PRIMARY KEY AUTOINCREMENT, " +
            "weight REAL, date TEXT)");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}

public Cursor getAll() {
    return (getReadableDatabase().rawQuery("SELECT _id, weight, date " +
            "FROM bmi_table ORDER BY _id", null));
}

public void insert(Double weight, String date) {
    ContentValues cv = new ContentValues();

    cv.put("weight", weight);
    cv.put("date", date);

    getWritableDatabase().insert("bmi_table", "weight", cv);
}

public double getWeight(Cursor c) {
    return (c.getDouble(1));
}

public String getDate(Cursor c) {
    return (c.getString(2));
}
}

And here is my code for adding data to GraphView:

private DataPoint[] getDataPoint() {
    String[] columns = {"Date", "Weight"};
    DataPoint[] dp = new DataPoint[cursor.getCount()];

    for (int i = 0; i < cursor.getCount(); i++) {
        cursor.moveToNext();
        dp [i] = new DataPoint(helper.getDate(cursor), helper.getWeight(cursor));
    }
}

I know I can't do this dp [i] = new DataPoint(helper.getDate(cursor), helper.getWeight(cursor)); because the date is stored as String. So is there any way which I can store the date as int or long?

Answer 1

You can add the current timestamp to your database entry and read the date out of this

date + " TIMESTAMP DEFAULT CURRENT_TIMESTAMP"

The format of a TIMESTAMP is YYYY-MM-DD HH:MM:SS at the second when you create the entry.

So you dont have to create it by your own. If I only need the date I read the line out an split the text. The advantage is that when sorting the entries by time, the seconds are also taken into account.

Update: Your table should look somethink like this

@Override
public void onCreate(SQLiteDatabase db) {
   db.execSQL("CREATE TABLE bmi_table ( _id INTEGER PRIMARY KEY AUTOINCREMENT, " +
   "weight REAL, " +
    date + " TIMESTAMP DEFAULT CURRENT_TIMESTAMP" +");"
}