安卓中的简单操作文件（登陆界面）

package com.ststudy.rwInRow;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

/**
 * Created by aaron on 9/1/15.
 */
public class RwInRom extends Activity {

    private EditText mEtName = null;
    private EditText mEtPassWord = null;
    private CheckBox mCbRe = null;
    private Button mBtLogin = null;

    private File mFile = null;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mFile = new File("/data/data/com.ststudy.rwInRow/test");
        login();
    }

    public void login()
    {
        mEtName = (EditText) findViewById(R.id.etName);
        mEtPassWord = (EditText) findViewById(R.id.etPassWord);
        mCbRe = (CheckBox) findViewById(R.id.cbRe);
        mBtLogin = (Button) findViewById(R.id.btLogin);

        mBtLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

//        获取用户名和密码
                String _name = mEtName.getText().toString();
                String _password = mEtPassWord.getText().toString();

                if (mCbRe.isChecked())
                {
                    try {
                        FileOutputStream _fos = new FileOutputStream(mFile);
                        _fos.write((_name + "##" + _password).getBytes());
                        _fos.close();

                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }

                Toast.makeText(RwInRom.this,"登陆成功",Toast.LENGTH_SHORT).show();
//                Log.v("Login","登陆成功");

            }
        });
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <EditText
            android:id="@+id/etName"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="请输入用户名"/>

    <EditText
            android:id="@+id/etPassWord"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:inputType="textPassword"
            android:hint="请输入密码"/>
    <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
        <CheckBox
                android:id="@+id/cbRe"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerVertical="true"
                android:text="下次自动登陆"/>
        <Button
                android:id="@+id/btLogin"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_alignParentRight="true"
                android:text="登陆"/>
    </RelativeLayout>

</LinearLayout>