《Android移动应用基础教程》之保存QQ账号和密码移动开发MrSuper王的博客-

FileSaveQQ.java

package njitt.software.saveqq;  import android.content.Context;  import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.util.HashMap; import java.util.Map;  public class FileSaveQQ {     //保存QQ账号和登录密码到data.txt文件中     public static boolean saveUserInfo(Context context, String account, String             password) {         FileOutputStream fos = null;         try {             //获取文件的输出流对象fos             fos = context.openFileOutput("data.txt",                     Context.MODE_PRIVATE);             //将数据转换为字节码的形式写入data.txt文件中             fos.write((account + ":" + password).getBytes());             return true;         } catch (Exception e) {             e.printStackTrace();             return false;         }finally {             try {                 if(fos != null){                     fos.close();                 }             } catch (IOException e) {                 e.printStackTrace();             }         }     }     //从data.txt文件中获取存储的QQ账号和密码     public static Map<String, String> getUserInfo(Context context) {         String content = "";         FileInputStream fis = null;         try {             //获取文件的输入流对象fis             fis = context.openFileInput("data.txt");             //将输入流对象中的数据转换为字节码的形式             byte[] buffer = new byte[fis.available()];             fis.read(buffer);//通过read()方法读取字节码中的数据             content = new String(buffer); //将获取的字节码转换为字符串             Map<String, String> userMap = new HashMap<String, String>();             String[] infos = content.split(":");//将字符串以“：”分隔后形成一个数组的形式             userMap.put("account", infos[0]);   //将数组中的第一个数据放入userMap集合中             userMap.put("password", infos[1]); //将数组中的第二个数据放入userMap集合中             return userMap;         } catch (Exception e) {             e.printStackTrace();             return null;         }finally {             try {                 if(fis != null){                     fis.close();                 }             } catch (IOException e) {                 e.printStackTrace();             }         }     } }  

MainActivity.java

package njitt.software.saveqq;  import androidx.appcompat.app.AppCompatActivity;  import android.os.Bundle; import android.text.TextUtils; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.Toast;  import java.util.Map;   public class MainActivity extends AppCompatActivity implements View.OnClickListener {     private EditText et_account;   //账号输入框     private EditText et_password; //密码输入框     private Button btn_login;      //登录按钮     @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         initView();         //通过工具类FileSaveQQ中的getUserInfo()方法获取QQ账号和密码信息         // Map<String, String> userInfo = FileSaveQQ.getUserInfo(this);         Map<String, String> userInfo = SPSaveQQ.getUserInfo(this);         if (userInfo != null) {             et_account.setText(userInfo.get("account"));   //将获取的账号显示到界面上             et_password.setText(userInfo.get("password")); //将获取的密码显示到界面上         }     }     private void initView() {         et_account = (EditText) findViewById(R.id.et_account);         et_password = (EditText) findViewById(R.id.et_password);         btn_login = (Button) findViewById(R.id.btn_login);         //设置按钮的点击监听事件         btn_login.setOnClickListener(this);     }     @Override     public void onClick(View v) {         switch (v.getId()) {             case R.id.btn_login:                 //当点击登录按钮时，获取界面上输入的QQ账号和密码                 String account = et_account.getText().toString().trim();                 String password = et_password.getText().toString();                 //检验输入的账号和密码是否为空                 if (TextUtils.isEmpty(account)) {                     Toast.makeText(this, "请输入QQ账号", Toast.LENGTH_SHORT).show();                     return;                 }                 if (TextUtils.isEmpty(password)) {                     Toast.makeText(this, "请输入密码", Toast.LENGTH_SHORT).show();                     return;                 }                 Toast.makeText(this, "登录成功", Toast.LENGTH_SHORT).show();                 //保存用户信息                 boolean isSaveSuccess = FileSaveQQ.saveUserInfo(this, account,                         password);                 /*  boolean isSaveSuccess = SPSaveQQ.saveUserInfo(this, account, password);*/                 if (isSaveSuccess) {                     Toast.makeText(this, "保存成功", Toast.LENGTH_SHORT).show();                 } else {                     Toast.makeText(this, "保存失败", Toast.LENGTH_SHORT).show();                 }                 break;         }     } }   

SPSaveQQ.java

package njitt.software.saveqq;   import android.content.Context; import android.content.SharedPreferences;  import java.util.HashMap; import java.util.Map;  public class SPSaveQQ{     // 保存QQ账号和登录密码到data.xml文件中     public static boolean saveUserInfo(Context context, String account,                                        String password) {         SharedPreferences sp = context.getSharedPreferences("data",                 Context.MODE_PRIVATE);         SharedPreferences.Editor edit = sp.edit();         edit.putString("userName", account);         edit.putString("pwd", password);         edit.commit();         return true;     }     //从data.xml文件中获取存储的QQ账号和密码     public static Map<String, String> getUserInfo(Context context) {         SharedPreferences sp = context.getSharedPreferences("data",                 Context.MODE_PRIVATE);         String account = sp.getString("userName", null);         String password = sp.getString("pwd", null);         Map<String, String> userMap = new HashMap<String, String>();         userMap.put("account", account);         userMap.put("password", password);         return userMap;     } }  

activity_main.xml

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:background="#E6E6E6"     android:orientation="vertical"     android:padding="10dp">     <ImageView         android:layout_width="70dp"         android:layout_height="70dp"         android:layout_centerHorizontal="true"         android:layout_gravity="center_horizontal"         android:layout_marginTop="30dp"         android:src="@drawable/head" />     <LinearLayout         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:layout_marginTop="15dp"         android:background="@android:color/white"         android:orientation="horizontal">         <TextView             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:padding="10dp"             android:text="账号:"             android:textColor="#000"             android:textSize="20sp" />         <EditText             android:id="@+id/et_account"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_marginLeft="5dp"             android:background="@null"             android:padding="10dp" />     </LinearLayout>     <LinearLayout         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:layout_marginTop="10dp"         android:background="@android:color/white"         android:orientation="horizontal">         <TextView             android:id="@+id/tv_password"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:padding="10dp"             android:text="密码:"             android:textColor="#000"             android:textSize="20sp" />         <EditText             android:id="@+id/et_password"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_marginLeft="5dp"             android:background="@null"             android:inputType="textPassword"             android:padding="10dp" />     </LinearLayout>     <Button         android:id="@+id/btn_login"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:layout_marginTop="25dp"         android:background="#3C8DC4"         android:text="登录"         android:textColor="@android:color/white"         android:textSize="20sp" /> </LinearLayout>  

实现效果如下：