Android 模拟登陆 保存密码（信息）到手机中 文件信息读取

package com.wuyou.login;



import java.io.IOException;

import java.util.Map;



import android.app.Activity;

import android.os.Bundle;

import android.text.TextUtils;

import android.util.Log;

import android.view.Menu;

import android.view.View;

import android.widget.CheckBox;

import android.widget.EditText;

import android.widget.Toast;



import com.wuyou.service.LoginService;



public class MainActivity extends Activity {



    private CheckBox checkBox;

    private EditText usernamEditText;

    private EditText passwordeEditText;



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);



        checkBox = (CheckBox) this.findViewById(R.id.cb);

        usernamEditText = (EditText) this.findViewById(R.id.username);

        passwordeEditText = (EditText) this.findViewById(R.id.password);



        // 将之前保存在本地的账号密码取出并设置到文本框中

        try {

            Map<String, String> map = LoginService.getInfo(this);

            usernamEditText.setText(map.get("username"));

            passwordeEditText.setText(map.get("password"));



        } catch (Exception e) {

            Log.i("main", "取不出账号密码");

        }



    }



    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.

        getMenuInflater().inflate(R.menu.main, menu);

        return true;

    }



    /**

     * 点击“登陆”按钮触发的时间

     * 

     * @param v

     */

    public void login(View v) {

        Log.i("login", "在登陆中");

        String username = usernamEditText.getText().toString().trim();

        String password = passwordeEditText.getText().toString().trim();

        if (TextUtils.isEmpty(username) || TextUtils.isEmpty(password)) {

            Toast.makeText(this, "用户名和账号不能为空！", Toast.LENGTH_SHORT).show();

        } else {

            // 判断是否选择了记住密码

            if (checkBox.isChecked()) {

                try {

                    LoginService.saveInfo(this, username, password);

                    Toast.makeText(this, "记住密码成功！", Toast.LENGTH_SHORT).show();

                } catch (IOException e) {

                    Toast.makeText(this, "无法记住密码", Toast.LENGTH_SHORT).show();

                }

            }

            if ("zhangsan".equals(username) && "123".equals(password)) {

                Toast.makeText(this, "登陆成功！", Toast.LENGTH_SHORT).show();

            } else {

                Toast.makeText(this, "账号密码有误！", Toast.LENGTH_SHORT).show();

            }

        }



    }



}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context=".MainActivity" >



    <TextView

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="请输入账号" />



    <EditText

        android:id="@+id/username"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content" />



    <TextView

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="请输入密码" />



    <EditText

        android:id="@+id/password"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content" />



    <RelativeLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content" >



        <CheckBox

            android:id="@+id/cb"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:checked="true"

            android:text="记住密码" />



        <!-- 记住login的方法有一个参数View -->

        <Button

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:layout_alignParentRight="true"

            android:onClick="login"

            android:text="登陆" />

    </RelativeLayout>



</LinearLayout>

package com.wuyou.service;



import java.io.BufferedReader;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileWriter;

import java.io.IOException;

import java.io.InputStreamReader;

import java.util.HashMap;

import java.util.Map;



import android.content.Context;



public class LoginService {



    public static void saveInfo(Context context, String username,

            String password) throws IOException {

        File file = new File(context.getFilesDir(), "info.txt");

        FileWriter fileWriter = new FileWriter(file);

        fileWriter.write(username + "##" + password);

        fileWriter.close();

    }



    public static Map<String, String> getInfo(Context context)

            throws IOException {
　　　　 //这里只做简单的保存，如果要保存配置文件信息，可以使用SharedPreference类保存，请关注本类别的该文章

        File file = new File(context.getFilesDir(),"info.txt");

        Map<String, String> map = new HashMap<String, String>();

        BufferedReader bf = new BufferedReader(new InputStreamReader(

                new FileInputStream(file)));

        String info = bf.readLine();

        String username = "";

        String password = "";

        if (info != null) {

            String[] infos = info.split("##");

            username = infos[0];

            password = infos[1];

            map.put("username", username);

            map.put("password", password);

            

        }

        bf.close();

        return map;

    }

}