Confuse Inserting CSV file to SQLite Database Android Studio

i am now working on a little project on Android Studio. Here i want to insert some data to SQLite Database since the first the app run. Because, the app need the data to run (this is a Quiz app) and the question is stored in a CSV file. I have doing some stuff like this

public class DatabaseHelper extends SQLiteOpenHelper {
public static final String MyVillageSoftware = "MyVillageSoftware";
public static final String DATABASE_NAME = "Question.db";
public static final String table_Question = "table_question";

public static final String COL1 = "QuestId";
public static final String COL2 = "A";
public static final String COL3 = "B";
public static final String COL4 = "C";
public static final String COL5 = "D";
public static final String COL6 = "aExplain";
public static final String COL7 = "bExplain";
public static final String COL8 = "cExplain";
public static final String COL9 = "dExplain";
public static final String COL10 = "_id";
//TOL for transaction Coloumn
SQLiteDatabase db;

private static final String TAG = DatabaseHelper.class.getSimpleName();



public DatabaseHelper(Context context) {
    super(context, DATABASE_NAME, null, 1);

}

@Override
public void onCreate(SQLiteDatabase db) {

    db.execSQL("Create table " + table_Question +
            " (QuestId Integer PRIMARY KEY, " +
            "A Text," +
            "B Text," +
            "C Text" +
            "D Text," +
            "aExplain Text," +
            "bExplain Text," +
            "cExplain Text," +
            "dExplain Text," +
            "_id Text)");

}

public void loadCSV2(){
    String mCSVfile = "file.csv";
    Context context;
    AssetManager manager = context.getAssets();
    InputStream inStream = null;
    try {
        inStream = manager.open(mCSVfile);
    } catch (IOException e) {
        e.printStackTrace();
    }

    BufferedReader buffer = new BufferedReader(new InputStreamReader(inStream));
    String line = "";
    db.beginTransaction();
    try {
        while ((line = buffer.readLine()) != null) {
            String[] colums = line.split(",");
            if (colums.length != 4) {
                Log.d("CSVParser", "Skipping Bad CSV Row");
                continue;
            }
            ContentValues cv = new ContentValues(3);
            cv.put(COL1, colums[0].trim());
            cv.put(COL2, colums[1].trim());
            cv.put(COL3, colums[2].trim());
            cv.put(COL4, colums[3].trim());
            cv.put(COL5, colums[4].trim());
            cv.put(COL6, colums[5].trim());
            cv.put(COL7, colums[6].trim());
            cv.put(COL8, colums[7].trim());
            cv.put(COL9, colums[8].trim());
            db.insert(table_Question, null, cv);
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
    db.setTransactionSuccessful();
    db.endTransaction();

}



public List<String> getAllCategory() {
    List<String> AllCategoryList = new ArrayList<String>();
    List<String> AllCategIdList = new ArrayList<String>();

    String selectQuery = "SELECT * FROM " + table_Question;
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);



    if (cursor.moveToFirst()) {
        do {
            String Id = cursor.getString(0);
            String A = cursor.getString(1);
            String B = cursor.getString(2);
            String C = cursor.getString(3);
            String D = cursor.getString(4);
            String aExplain = cursor.getString(5);
            String bExplain = cursor.getString(6);
            String cExplain = cursor.getString(7);
            String dExplain = cursor.getString(8);

        } while (cursor.moveToNext());
    }
    cursor.close();
    db.close();
    return AllCategoryList;
}


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

}

}

but i got error on this line :

 AssetManager manager = context.getAssets();

it said

Error:(67, 32) error: variable context might not have been initialized

I don't know what happen, please master help me. I am so newbie on android programming.

Thanks Before.