Helper Class Android SQLiteOpenHelper SQLiteDatabase

import android.database.sqlite.SQLiteOpenHelper
import android.database.sqlite.SQLiteDatabase
import android.content.ContentValues
import android.content.Context
import android.database.Cursor
class Helper (context: Context?):SQLiteOpenHelper(context,DATABASE_NAME,null,1)
{
    override fun onCreate(db: SQLiteDatabase) {
        db.execSQL(
"CREATE TABLE " + TABLE_NAME + "(" 
+ KEY_ID + " INTEGER PRIMARY KEY, "
 + KEY_NOM + " TEXT," 
+ KEY_VILLE + " TEXT," 
+ KEY_LAT + " TEXT, " 
+ KEY_LONG + " TEXT )"
        )
    }
    override fun onUpgrade(
        db: SQLiteDatabase, oldVersion: Int,
        newVersion: Int
    ) {
    }
    fun addCentre(centre: Centre) {
        val db = this.writableDatabase
        val cv = ContentValues()
        cv.put(KEY_NOM, centre.getNom())
        cv.put(KEY_VILLE, centre.getVille())
        cv.put(KEY_LAT, centre.getLatitude())
        cv.put(KEY_LONG, centre.getLongitude())
        db.insert(TABLE_NAME, null, cv)
        db.close()
    }
    fun fetchAllCenter(): Cursor {
        val db = this.readableDatabase
        /* if (mCursor != null) {
        mCursor.moveToFirst();
        }*/return db.query(
            TABLE_NAME, arrayOf(
                KEY_ID,
                KEY_NOM, KEY_VILLE, KEY_LAT, KEY_LONG
            ),
            null, null, null, null, null
        )
    }
    fun deleteCenter(id: Int) {
        val db = this.writableDatabase
        db.delete(TABLE_NAME, KEY_ID + "=?", arrayOf(id.toString()))
    }
    fun updateCentre(id: Int, centre: Centre) {
        val db = this.readableDatabase
        val cv = ContentValues()
        cv.put(KEY_NOM, centre.getNom())
        cv.put(KEY_VILLE, centre.getVille())
        cv.put(KEY_LAT, centre.getLatitude())
        cv.put(KEY_LONG, centre.getLongitude())
        db.update(TABLE_NAME, cv, KEY_ID + "=?", arrayOf(id.toString()))
    }
    fun getCentre(id: Int): Centre {
        val db = this.readableDatabase
        val c = db.query(
            TABLE_NAME,
            arrayOf(
                KEY_ID,
                KEY_NOM,
                KEY_VILLE,
                KEY_LAT,
                KEY_LONG
            ),
            KEY_ID + "=?",
            arrayOf(id.toString()),
            null,
            null,
            null,
            null
        )
        c?.moveToFirst()
        return Centre(
            c!!.getInt(0), c.getString(1),
            c.getString(2), c.getString(3),
            c.getString(4)
        )
    }
    companion object {
        private const val DATABASE_NAME = "centerManger"
        private const val TABLE_NAME = "centre"
        private const val KEY_ID = "_id"
        private const val KEY_NOM = "nom"
        private const val KEY_VILLE = "ville"
        private const val KEY_LAT = "latitude"
        private const val KEY_LONG = "longitude"
    }
}