I am trying to create a database for login but there is an error in my LoginDatabaseAdapter.java class [duplicate]

This question is an exact duplicate of:

• The constructor DataBaseHelper(Context, String, null, int) is undefined,The method getWritableDatabase() is undefined for the type DataBaseHelper

The error shown is "The constructor DataBaseHelper(Context, String, null, int) is undefined" in line number 27 and also on line number 31 one more error is "The method getWritableDatabase() is undefined for the type DataBaseHelper". Please help in solving these error.

LoginDataBaseAdapter class

package com.example.firstapp;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;

 public class LoginDataBaseAdapter 
{
    static final String DATABASE_NAME = "login.db";
    static final int DATABASE_VERSION = 1;
    public static final int NAME_COLUMN = 1;
    // TODO: Create public field for each column in your table.
    // SQL Statement to create a new database.
    static final String DATABASE_CREATE = "create table "+"LOGIN"+
                                 "( " +"ID"+" integer primary key autoincrement,"+ "USERNAME       

 text,PASSWORD text); ";
    // Variable to hold the database instance
    public  SQLiteDatabase db;
    // Context of the application using the database.
    private final Context context;
    // Database open/upgrade helper
    private DataBaseHelper dbHelper;
    public  LoginDataBaseAdapter(Context _context) 
    {
        context = _context;
        dbHelper = new DataBaseHelper(context, DATABASE_NAME, null, DATABASE_VERSION);
    }
    public  LoginDataBaseAdapter open() throws SQLException 
    {
        db = dbHelper.getWritableDatabase();
        return this;
    }
    public void close() 
    {
        db.close();
    }

    public  SQLiteDatabase getDatabaseInstance()
    {
        return db;
    }

    public void insertEntry(String userName,String password)
    {
       ContentValues newValues = new ContentValues();
        // Assign values for each row.
        newValues.put("USERNAME", userName);
        newValues.put("PASSWORD",password);

        // Insert the row into your table
        db.insert("LOGIN", null, newValues);
        ///Toast.makeText(context, "Reminder Is Successfully Saved", Toast.LENGTH_LONG).show();
    }
    public int deleteEntry(String UserName)
    {
        //String id=String.valueOf(ID);
        String where="USERNAME=?";
        int numberOFEntriesDeleted= db.delete("LOGIN", where, new String[]{UserName}) ;
       // Toast.makeText(context, "Number fo Entry Deleted Successfully :   

 "+numberOFEntriesDeleted, Toast.LENGTH_LONG).show();
        return numberOFEntriesDeleted;
    }   
    public String getSinlgeEntry(String userName)
    {
        Cursor cursor=db.query("LOGIN", null, " USERNAME=?", new String[]{userName}, null, null,   

 null);
        if(cursor.getCount()<1) // UserName Not Exist
        {
            cursor.close();
            return "NOT EXIST";
        }
        cursor.moveToFirst();
        String password= cursor.getString(cursor.getColumnIndex("PASSWORD"));
        cursor.close();
        return password;                
    }
    public void  updateEntry(String userName,String password)
    {
        // Define the updated row content.
        ContentValues updatedValues = new ContentValues();
        // Assign values for each row.
        updatedValues.put("USERNAME", userName);
        updatedValues.put("PASSWORD",password);

        String where="USERNAME = ?";
        db.update("LOGIN",updatedValues, where, new String[]{userName});               
    }       
  }

DataBaseHelper class

package com.example.firstapp;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

  public class DataBaseHelper extends SQLiteOpenHelper
{
public DataBaseHelper(Context context, String name,CursorFactory factory, int version) 
{
           super(context, name, factory, version);
}
// Called when no database exists in disk and the helper class needs
// to create a new one.
@Override
public void onCreate(SQLiteDatabase _db) 
{
        _db.execSQL(LoginDataBaseAdapter.DATABASE_CREATE);

}
// Called when there is a database version mismatch meaning that the version
// of the database on disk needs to be upgraded to the current version.
@Override
public void onUpgrade(SQLiteDatabase _db, int _oldVersion, int _newVersion) 
{
        // Log the version upgrade.
        Log.w("TaskDBAdapter", "Upgrading from version " +_oldVersion + " to " +_newVersion + ",     

 which will destroy all old data");


        // Upgrade the existing database to conform to the new version. Multiple
        // previous versions can be handled by comparing _oldVersion and _newVersion
        // values.
        // The simplest case is to drop the old table and create a new one.
        _db.execSQL("DROP TABLE IF EXISTS " + "TEMPLATE");
        // Create a new one.
        onCreate(_db);
 }


}