Android DBHelper Example

DBHelper.java

public class DBHelper extends SQLiteOpenHelper{
    
    // Database Information
    private static final int DATABASE_VERSION = 1;
    private static final String DATABASE_NAME = "sensor_data";
    
    // Table and Column Names
    public static final String TABLE_ACC = "acc";
    private static final String CURRENT_TIMESTAMP = "CURRENT_TIMESTAMP";
    private static final String KEY_ID = "id";
    private static final String KEY_CREATED_AT = "created_at";

    // Specific Table - column nmaes
    private static final String KEY_X = "x";
    private static final String KEY_Y = "y";
    private static final String KEY_Z = "z";
    private static final String CREATE_TABLE_ACC = "CREATE TABLE "
            + TABLE_ACC + "("
            + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
            + KEY_X + " TEXT, "
            + KEY_Y + " TEXT, "
            + KEY_Z + " TEXT, "
            + KEY_CREATED_AT  + " DATETIME DEFAULT " + CURRENT_TIMESTAMP + " )";
    

    public DBHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(CREATE_TABLE_ACC);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_ACC);
        onCreate(db);
    }

    public void insertAcc(String x, String y, String z){
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(KEY_X, x);
        values.put(KEY_Y, y);
        values.put(KEY_Z, z);
        //db.insert(TABLE_ACC, null, values);

        long rowInserted = db.insert(TABLE_ACC, null, values);
        if(rowInserted != -1)
            Log.d("DATABASE_OPERATION","ACC_INSERTED_" + rowInserted);
        else
            Log.d("DATABASE_OPERATION","ACC_INSERTED_FAILED" + rowInserted);

    }

    public void exportDB(String table_name, int col_count, Context c) {
        Log.d("CSV_OPERATION_STARTED","STARTED");
        File exportDir = new File(Environment.getExternalStorageDirectory(), "");
        Log.d("CSV_OPERATION_PATH",String.valueOf(Environment.getExternalStorageDirectory()));
        if (!exportDir.exists())
        {
            exportDir.mkdirs();
        }

        File file = new File(exportDir, "csvname-" + table_name + ".csv");
        try
        {
            file.createNewFile();
            CSVWriter csvWrite = new CSVWriter(new FileWriter(file));
            SQLiteDatabase db = this.getReadableDatabase();

            Cursor curCSV = db.rawQuery("SELECT * FROM " + table_name,null);
            csvWrite.writeNext(curCSV.getColumnNames());
            Log.d("CSV_OPERATION_WRITE","STARTED");
            while(curCSV.moveToNext())
            {
                //Which column you want to exprort
                //String arrStr[] ={curCSV.getString(0),curCSV.getString(1), curCSV.getString(2)};
                List<String> list = new ArrayList<String>();
                String arrStr[];
                for(int i=0;i<col_count+2;i++){
                    list.add(curCSV.getString(i));
                }
                arrStr = list.toArray(new String[0]);
                csvWrite.writeNext(arrStr);
            }
            csvWrite.close();
            curCSV.close();
            Intent newIntent = new Intent(Intent.ACTION_VIEW);
            String mimeType ="text/csv";
            newIntent.setDataAndType(FileProvider.getUriForFile(c, c.getPackageName()+".net.api_central.apps.sensortracker",file),mimeType);
            newIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            newIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
            try {
                c.startActivity(newIntent);
            } catch (ActivityNotFoundException e) {
                Toast.makeText(c, "No handler for this type of file.", Toast.LENGTH_LONG).show();
            }
        }
        catch(Exception sqlEx)
        {
            Log.e("CSV_OPERATION_FAILED", sqlEx.getMessage(), sqlEx);
        }
    }
}

MainActivity.java

public class MainActivity extends AppCompatActivity {
    DBHelper db;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        db = new DBHelper(getApplicationContext());
        
        //Inserting Data into DB
        db.insertAcc("1","2","3");
    }
}