How to fetch and show data (on new activity) from SQLite in android

I am confused what mistake i am making to fetch passWord against username (I am new here and to android :) so sorry if i make any mistake in asking question) Here's LoginDatabaseAdapter.java

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

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,MOBILENO int); ";
    // 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,String mobileNumber)
    {
       ContentValues newValues = new ContentValues();
        // Assign values for each row.
        newValues.put("USERNAME", userName);
        newValues.put("PASSWORD", password);
        newValues.put("MOBILENO", mobileNumber);

        // 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 getSingleEntry(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"));
        // String mobileNumber=cursor.getString(cursor.getColumnIndex("MOBILENO"));
        cursor.close();
        return "Password="+password;

    }
    public void  updateEntry(String userName,String password,String mobileNumber)
    {
        // Define the updated row content.
        ContentValues updatedValues = new ContentValues();
        // Assign values for each row.
        updatedValues.put("USERNAME", userName);
        updatedValues.put("PASSWORD", password);
        updatedValues.put("MOBILENO", mobileNumber);

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

and SignupActivity.java

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class SignUpActivity extends Activity
{
EditText     editTextUserName,editTextPassword,editTextConfirmPassword,editTextMobileNo;
Button btnCreateAccount;

Button btnfetch;
TextView sv;

LoginDataBaseAdapter loginDataBaseAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.signup);

    // get Instance  of Database Adapter
    loginDataBaseAdapter=new LoginDataBaseAdapter(this);
    loginDataBaseAdapter=loginDataBaseAdapter.open();

    // Get Refferences of Views
    editTextUserName=(EditText)findViewById(R.id.editTextUserName);
    editTextPassword=(EditText)findViewById(R.id.editTextPassword);
    editTextConfirmPassword=(EditText)findViewById(R.id.editTextConfirmPassword);
    editTextMobileNo=(EditText)findViewById(R.id.editTextMobileNo);

    btnCreateAccount=(Button)findViewById(R.id.buttonCreateAccount);
    btnCreateAccount.setOnClickListener(new View.OnClickListener() {

    public void onClick(View v) {
        // TODO Auto-generated method stub

        String userName=editTextUserName.getText().toString();
        String password=editTextPassword.getText().toString();
        String confirmPassword=editTextConfirmPassword.getText().toString();
        String mobileNumber=editTextMobileNo.getText().toString();

        // check if any of the fields are vaccant
        if(userName.equals("")||password.equals("")||confirmPassword.equals("")||mobileNumber.equals(""))
        {
                Toast.makeText(getApplicationContext(), "Please Enter Your Details", Toast.LENGTH_LONG).show();
                return;
        }
        // check if both password matches
        if(!password.equals(confirmPassword))
        {
            Toast.makeText(getApplicationContext(), "Confirm Password does not match", Toast.LENGTH_LONG).show();
            return;
        }
        else
        {
            // Save the Data in Database
            loginDataBaseAdapter.insertEntry(userName, password,mobileNumber);
            Toast.makeText(getApplicationContext(), "Account Successfully Created ", Toast.LENGTH_LONG).show();
        }
    }
});

    btnfetch=(Button)findViewById(R.id.btnshow);
    btnfetch.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            sv=(TextView)findViewById(R.id.tvshow);
            String userName=editTextUserName.getText().toString();
            String pass=loginDataBaseAdapter.getSingleEntry(userName);
            sv.setText(pass);
        }
    }); 

}
@Override
protected void onDestroy() {
    // TODO Auto-generated method stub
    super.onDestroy();

    loginDataBaseAdapter.close();
 }  
}