Android实战教程第七篇之如何在内存中存储用户名和密码

<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: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"   android:orientation="vertical"    >    <EditText     android:id="@+id/et_name"     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:hint="请输入用户名"     />   <EditText     android:id="@+id/et_pass"     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"     android:orientation="horizontal"     >     <CheckBox        android:id="@+id/cb"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:text="记住用户名和密码"       android:layout_centerVertical="true"       />     <Button        android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_gravity="right"       android:text="登录"       android:layout_alignParentRight="true"       android:onClick="login"       />   </RelativeLayout> </LinearLayout> 

package com.itydl.rwinrom;  import java.io.BufferedReader; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.FileReader; import java.io.InputStreamReader;  import org.apache.http.entity.InputStreamEntity;  import android.os.Bundle; import android.annotation.SuppressLint; import android.app.Activity; import android.view.Menu; import android.view.View; import android.widget.CheckBox; import android.widget.EditText; import android.widget.Toast;  public class MainActivity extends Activity {    private EditText et_name;   private EditText et_pass;    @Override   protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main);          et_name = (EditText) findViewById(R.id.et_name);     et_pass = (EditText) findViewById(R.id.et_pass);          readAccount();//在onCreate中读取原因是，活动一创建就读取用户名和密码进行回显。        }    public void readAccount(){     File file = new File("data/data/com.itydl.rwinrom/info.txt");     if(file.exists()){       try {         // FileInputStream fis = new FileInputStream(file);         // //把字节流转换成字符流         // BufferedReader br = new BufferedReader(new         // InputStreamReader(fis));                  BufferedReader br = new BufferedReader(new FileReader(file));         //读取txt文件里的用户名和密码         String text = br.readLine();         String[] s = text.split("##");//正则表达                  et_name.setText(s[0]);//ctrl+1提取全局变量         et_pass.setText(s[1]);       } catch (Exception e) {         // TODO Auto-generated catch block         e.printStackTrace();       }     }   }    public void login(View v){          String name = et_name.getText().toString();     String pass = et_pass.getText().toString();          CheckBox cb = (CheckBox) findViewById(R.id.cb);     //判断选框是否被勾选     if(cb.isChecked()){       //data/data/com.itheima.rwinrom:这就是内部存储空间的路径       File file = new File("data/data/com.itydl.rwinrom/info.txt");//这个路径是安卓特有的文件夹       FileOutputStream fos;       try {         fos = new FileOutputStream(file);         //勾选了复选框，会把用户名密码存入内部存储位置         fos.write((name + "##" + pass).getBytes());         fos.close();       } catch (Exception e) {         // TODO Auto-generated catch block         e.printStackTrace();       }     }          //创建并显示吐司对话框     Toast.makeText(this, "登录成功", 0).show();   }    }