安卓数据保存登录状态

public class loginServe {
    public static boolean saveUserInfo(Context context,String username,String password){
        try {
            File file = new File(context.getFilesDir(),"info.txt");
            FileOutputStream fos = new FileOutputStream(file);
            fos.write((username+"##"+password).getBytes());
            fos.close();
            return true;
        } catch (Exception e) {
            // TODO 自动生成 catch 块
            e.printStackTrace();
            return false;
        }
    }

    //获取保存的数据
    public static Map, String> getSaveUserInfo(Context context){
        File file = new File(context.getFilesDir(),"info.txt");
        try {
            FileInputStream fis = new FileInputStream(file);
            BufferedReader br = new BufferedReader(new InputStreamReader(fis));
            String str = br.readLine();
            String[] infos = str.split("##");
            Map, String> map = new HashMap,String>();
            map.put("username", infos[0]);
            map.put("password", infos[1]);
            return map;
        } catch (Exception e) {
            // TODO 自动生成 catch 块
            e.printStackTrace();
            return null;
        }
    }
}

这是封装的一个保存数据的类

public class MainActivity extends Activity {
   private static final String Tag = "MainActivity";
   private EditText et_name;
   private EditText et_password;
   private CheckBox cb;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      et_name = (EditText) findViewById(R.id.et_name);
      et_password = (EditText) findViewById(R.id.et_psw);
      cb = (CheckBox) findViewById(R.id.cb_remeber_name);
      Map, String> map = loginServer.getSaveUserInfo(this);
      if(map!=null){
         et_name.setText(map.get("username"));
         et_password.setText(map.get("password"));
      }
   }
   //登录点击事件
    public void login(View view){
       String username = et_name.getText().toString().trim();
       String password = et_password.getText().toString().trim();
       if(TextUtils.isEmpty(username)||TextUtils.isEmpty(password)){
          Toast.makeText(this, "用户名或者密码不能为空", Toast.LENGTH_SHORT).show();
       }else {
          //判断是否保存密码
          if (cb.isChecked()) {
             //保存用户密码
            Log.i(Tag, "需要保存用户名密码");
            boolean result = loginServer.saveUserInfo(this,username,password);
            if(result){
               Toast.makeText(this, "保存数据成功", Toast.LENGTH_SHORT).show();
            }
         } 
               //登录
            if("wangzhixin".equals(username)&&("123".equals(password))){
            Toast.makeText(this, "登录成功", Toast.LENGTH_SHORT).show();
         } else{
            Toast.makeText(this, "登录失败", Toast.LENGTH_SHORT).show();
         }
      }
    }
}