db_test_class.java

package com.test.db;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
import java.util.List;
import com.test.db.MainActivity.Data;

public class MyDb extends SQLiteOpenHelper {

    public static final String TAG = "MyDb";
    public static final int VERSION = 1;
    public static final String DATABASENAME = "mydb";

    public MyDb(Context context) {
        super(context, DATABASENAME, null, VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE IF NOT EXISTS data"
                + " (ID INTEGER PRIMARY KEY, "
                + "DATA_ID TEXT, "
                + "VALUE TEXT);");
    }

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

    }

    public synchronized boolean addData(List<Data> _objects) {
        final SQLiteDatabase db = this.getWritableDatabase();
        boolean retval = false;
        try {
            for (Data object : _objects) {
                ContentValues contentValues = new ContentValues();
                contentValues.put("ID", object.id);
                contentValues.put("DATA_ID", object.dataId);
                contentValues.put("VALUE", object.value);
                db.insert("data", null, contentValues);
                //  db.insertWithOnConflict("data", null, contentValues, SQLiteDatabase.CONFLICT_REPLACE);
            }
            retval = true;
        } catch (Exception ex) {
            Log.e(TAG, "addData exception", ex);
        } finally {
            db.close();
        }
        return retval;
    }

    public synchronized String getDataValue(long _id) {
        final SQLiteDatabase db = this.getReadableDatabase();
        String retval = null;
        try {
            Cursor cursor = db.query("data", new String[]{"VALUE"},
                    "ID = ?", new String[]{String.valueOf(_id)}, null, null, null);
            if (cursor != null) {
                if (cursor.moveToFirst()) {
                    do {
                        retval = cursor.getString(0);
                    } while (cursor.moveToNext());
                }
            }
        } catch (Exception ex) {
            retval = null;
            Log.e(TAG, "Cannot get data value:", ex);
        } finally {
            db.close();
        }
        return retval;
    }
}