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;
}
}