保存数据到手机内存代码优化(QQ登录保存密码)

package com.itheima28.qqlogin;

import java.io.File;
import java.util.Map;

import com.itheima28.qqlogin.utils.Utils;
import com.itheima28.qqlogin.utils.UtilsOfSDCard;
import com.itheima28.qqlogin.R;

import android.app.Activity;
import android.os.Bundle;
import android.text.TextUtils;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener {

  private static final String TAG = "MainActivity";
  private EditText etNumber;
  private EditText etPassword;
  private CheckBox cbRemerberPWD;
  private Map<String, String> userInfoMap;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
  
    //  /data/data/包名/files
    /*
    this.getFilesDir-- /data/data/com.itheima28.qqlogin/files
     */
    File file = this.getFilesDir();
    
    System.out.println(file.toString());
    
    etNumber = (EditText) findViewById(R.id.et_number);
    etPassword = (EditText) findViewById(R.id.et_password);
  
    cbRemerberPWD = (CheckBox) findViewById(R.id.cb_remember_pwd);
    Button btnLogin = (Button) findViewById(R.id.btn_login);
  
  
    btnLogin.setOnClickListener(this);
    
    //回显
    userInfoMap = Utils.getUserInfo(this);
    if(userInfoMap != null){
      etNumber.setText(userInfoMap.get("number"));
      etPassword.setText(userInfoMap.get("password"));
    } 
    
  }

  @Override
  public void onClick(View v) {
    //执行登录的方法
    
    //1.取出号码和密码
    String number = etNumber.getText().toString();
    String password = etPassword.getText().toString();
    
    
    
    if(TextUtils.isEmpty(number)||TextUtils.isEmpty(password)){
      //Toast--弹出吐司,下面的业务就不执行了
      Toast.makeText(this, "请正确输入", Toast.LENGTH_SHORT).show();
      /*
       第一个参数为Context对象,MainActivity继承Context,所以用this就行了
      第二个参数时候提示的信息
      第三个参数持续的时间   Toast.LENGTH_SHORT--0秒    Toast.LENGTH_LONG--1秒
       */
    }
    
    //2.判断记住密码是否被选中,如果被选中,存起来
    if(cbRemerberPWD.isChecked()){
      //当前需要记住密码
      Log.i(TAG, "记住密码："+number + ","+password);
      
      boolean isSuccess = Utils.saveUserInfo(this,number, password);
      if(isSuccess){
         Toast.makeText(this, "保存成功", Toast.LENGTH_SHORT).show();
      }else{
         Toast.makeText(this, "保存失败", Toast.LENGTH_SHORT).show();
      }
    } 
    
    //3.登录成功
    Toast.makeText(this, "登录成功", Toast.LENGTH_SHORT).show();
  
  }

   
}

package com.itheima28.qqlogin.utils;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;

import android.content.Context;
import android.text.TextUtils;

public class Utils {
  
  
  
  /*
   * 保存存户信息
   * */
  public static boolean saveUserInfo(String number,String password){
    
    try {
      
      String path = "/data/data/com.itheima28.qqlogin/itheima28.txt";
      
      FileOutputStream fos = new FileOutputStream(path);
    
      //存储12345##6545564
      String date =  number + "##" + password;
      
      fos.write(date.getBytes());
      
      fos.flush();
      
      fos.close();
      
      return true;
    } catch (Exception e) {
      e.printStackTrace();
    }
    return false;
  }
  
  
  
  public static boolean saveUserInfo(Context context,String number,String password){
    
    try {
//      String path = "/data/data/com.itheima28.qqlogin/itheima28.txt";
      
      
      File filesDir = context.getFilesDir();
      
      File f = new File(filesDir,"itheima28.txt");
      
      FileOutputStream fos = new FileOutputStream(f);
    
      //存储12345##6545564
      String date =  number + "##" + password;
      
      fos.write(date.getBytes());
      
      fos.flush();
      
      fos.close();
      
      return true;
    } catch (Exception e) {
      e.printStackTrace();
    }
    return false;
  }
  
  
  /**
   * 返回用户信息
   * */
  public static Map<String,String> getUserInfo(){
    
    try {
      String path = "/data/data/com.itheima28.qqlogin/itheima28.txt";
      FileInputStream fis = new FileInputStream(path);
      
      //字符流对象
      BufferedReader reader = new BufferedReader(new InputStreamReader(fis));
      
      String text = reader.readLine();
      
      if(TextUtils.isEmpty(text)){
        String[] split = text.split("##");
        
        Map<String,String> userInfoMap = new HashMap<String, String>();
        userInfoMap.put("number", split[0]);
        userInfoMap.put("number", split[1]);
        return userInfoMap;
      }
      
    } catch (Exception e) {
      e.printStackTrace();
    }
    return null;
  }
  
  
  
  
  public static Map<String,String> getUserInfo(Context context){
    
    try {
//      String path = "/data/data/com.itheima28.qqlogin/itheima28.txt";
    
      File filesDir = context.getFilesDir();
      
      File f = new File(filesDir,"itheima28.txt");
      
      FileInputStream fis = new FileInputStream(f);
      
      //字符流对象
      BufferedReader reader = new BufferedReader(new InputStreamReader(fis));
      
      String text = reader.readLine();
      
      if(TextUtils.isEmpty(text)){
        String[] split = text.split("##");
        
        Map<String,String> userInfoMap = new HashMap<String, String>();
        userInfoMap.put("number", split[0]);
        userInfoMap.put("number", split[1]);
        return userInfoMap;
      }
      
    } catch (Exception e) {
      e.printStackTrace();
    }
    return null;
  }
}

<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" >

    <EditText 
        android:id="@+id/et_number"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入QQ号"
        />
     <EditText 
        android:id="@+id/et_password"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textPassword"
        android:hint="请输入密码"/>
    
     <CheckBox 
         android:id="@+id/cb_remember_pwd"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:checked="true"
         android:text="记住密码"/>
         <!-- checkedtrue代表选中 -->  
     
     <Button 
         android:id="@+id/btn_login"
         android:layout_height="wrap_content"
         android:layout_width="wrap_content"
         android:text="登录"/>
</LinearLayout>