基于IntentService的Android登录完整示例

               

1.后台使用简单的servlet，支持GET或POST。这个servlet最终返回给前台一个字符串flag，值是true或false，表示登录是否成功。

/*** Copyright(C) 2014** 模块名称：     * 子模块名称：   ** 备注：** 修改历史：* 2014-1-26 1.0  [email protected]  新建*/package cn.edu.hbcit.minicms.controller;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.log4j.Logger;import cn.edu.hbcit.minicms.dao.Login;import cn.edu.hbcit.minicms.util.PasswordEncodeBean;/** * 登录控制类 * 简要说明: * @author [email protected] * @version 1.00  2014-1-26下午07:21:13 新建 */public class LoginServlet extends HttpServlet { protected final static Logger log = Logger.getLogger(LoginServlet.class.getName()); /**  * Constructor of the object.  */ public LoginServlet() {  super(); } /**  * Destruction of the servlet. <br>  */ public void destroy() {  super.destroy(); // Just puts "destroy" string in log  // Put your code here } /**  * The doGet method of the servlet. <br>  */ public void doGet(HttpServletRequest request, HttpServletResponse response)   throws ServletException, IOException {  this.doPost(request, response); } /**  * The doPost method of the servlet. <br>  *  * This method is called when a form has its tag value method equals to post.  *   * @param request the request send by the client to the server  * @param response the response send by the server to the client  * @throws ServletException if an error occurred  * @throws IOException if an error occurred  */ public void doPost(HttpServletRequest request, HttpServletResponse response)   throws ServletException, IOException {  response.setContentType("text/html");  PrintWriter out = response.getWriter();  Boolean flag = false;  Login login = new Login();  PasswordEncodeBean encode = new PasswordEncodeBean();  String userName = request.getParameter("un");  String password = request.getParameter("pw");  flag = login.login(userName, encode.MD5Encode(password));  log.debug("登录结果是：" + flag);  out.print(flag);  out.flush();  out.close(); } /**  * Initialization of the servlet. <br>  *  * @throws ServletException if an error occurs  */ public void init() throws ServletException {  // Put your code here }}

2.在ADT中新建一个android工程，建立两个Activity，分别作为登录界面和登录成功界面。

activity_main.xml

<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:id="@+id/mainContent"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="TextView" />    <EditText        android:id="@+id/userName"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:ems="10"         android:inputType="text" />"    <EditText        android:id="@+id/password"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:ems="10"        android:inputType="textPassword" />    <Button        android:id="@+id/myButton"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Submit" /></LinearLayout>

activity_result.xml

<RelativeLayout 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=".ResultActivity" >    <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/hello_world" /></RelativeLayout>

3.HTTP的访问公共类，用于处理GET和POST请求

package edu.hbcit.testandroid.util;import java.util.ArrayList;import java.util.List;import java.util.Map;import org.apache.http.HttpResponse;import org.apache.http.NameValuePair;import org.apache.http.client.HttpClient;import org.apache.http.client.entity.UrlEncodedFormEntity;import org.apache.http.client.methods.HttpGet;import org.apache.http.client.methods.HttpPost;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.message.BasicNameValuePair;import org.apache.http.util.EntityUtils;import android.util.Log;public class HttpUtil{ // 创建HttpClient对象 public static HttpClient httpClient = new DefaultHttpClient(); public static final String BASE_URL =   "http://192.168.1.101:8080/server/"; //注意不要用127.0.0.1 /**  *   * @param url 发送请求的URL  * @return 服务器响应字符串  * @throws Exception  */ public static String getRequest(String url)  throws Exception {  // 创建HttpGet对象。  HttpGet get = new HttpGet(url);  // 发送GET请求  HttpResponse httpResponse = httpClient.execute(get);  // 如果服务器成功地返回响应  if (httpResponse.getStatusLine()   .getStatusCode() == 200){   // 获取服务器响应字符串   String result = EntityUtils.toString(httpResponse.getEntity());   return result;  }else{   Log.d("服务器响应代码", (new Integer(httpResponse.getStatusLine().getStatusCode())).toString());   return null;  }   } /**  *   * @param url 发送请求的URL  * @param params 请求参数  * @return 服务器响应字符串  * @throws Exception  */ public static String postRequest(String url, Map<String ,String> rawParams)throws Exception{  // 创建HttpPost对象。  HttpPost post = new HttpPost(url);  // 如果传递参数个数比较多的话可以对传递的参数进行封装  List<NameValuePair> params = new ArrayList<NameValuePair>();  for(String key : rawParams.keySet()){   //封装请求参数   params.add(new BasicNameValuePair(key , rawParams.get(key)));  }  // 设置请求参数  post.setEntity(new UrlEncodedFormEntity(params, "gbk"));  // 发送POST请求  HttpResponse httpResponse = httpClient.execute(post);  // 如果服务器成功地返回响应  if (httpResponse.getStatusLine().getStatusCode() == 200){   // 获取服务器响应字符串   String result = EntityUtils.toString(httpResponse.getEntity());   return result;  }  return null; }}

4.IntentService服务，用于在后台以队列方式处理耗时操作。

package edu.hbcit.testandroid.service;import java.util.HashMap;import edu.hbcit.testandroid.util.HttpUtil;import android.app.IntentService;import android.content.Intent;import android.util.Log;public class ConnectService extends IntentService { private static final String ACTION_RECV_MSG = "edu.hbcit.testandroid.intent.action.RECEIVE_MESSAGE"; public ConnectService() {  super("TestIntentService");  // TODO Auto-generated constructor stub } @Override protected void onHandleIntent(Intent intent) {  // TODO Auto-generated method stub  /**   * 经测试，IntentService里面是可以进行耗时的操作的    * IntentService使用队列的方式将请求的Intent加入队列，   * 然后开启一个worker thread(线程)来处理队列中的Intent     * 对于异步的startService请求，IntentService会处理完成一个之后再处理第二个     */  Boolean flag = false;  //通过intent获取主线程传来的用户名和密码字符串  String username = intent.getStringExtra("username");  String password = intent.getStringExtra("password");  flag = doLogin(username, password);  Log.d("登录结果", flag.toString());    Intent broadcastIntent = new Intent();  broadcastIntent.setAction(ACTION_RECV_MSG);          broadcastIntent.addCategory(Intent.CATEGORY_DEFAULT);    broadcastIntent.putExtra("result", flag.toString());  sendBroadcast(broadcastIntent); }   // 定义发送请求的方法  private Boolean doLogin(String username, String password)  {   String strFlag = "";   // 使用Map封装请求参数   HashMap<String, String> map = new HashMap<String, String>();   map.put("un", username);   map.put("pw", password);   // 定义发送请求的URL//   String url = HttpUtil.BASE_URL + "LoginServlet?un=" + username + "&pw=" + password;  //GET方式   String url = HttpUtil.BASE_URL + "LoginServlet"; //POST方式   Log.d("url", url);   Log.d("username", username);   Log.d("password", password);   try {   // 发送请求   strFlag = HttpUtil.postRequest(url, map);  //POST方式//    strFlag = HttpUtil.getRequest(url);  //GET方式   Log.d("服务器返回值", strFlag);  } catch (Exception e) {   // TODO Auto-generated catch block   e.printStackTrace();  }      if(strFlag.trim().equals("true")){    return true;   }else{    return false;   }     }}

5.在AndroidManifest.xml中注册IntentService。注意uses-permission节点，为程序开启访问网络的权限。

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="edu.hbcit.testandroid"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="9"        android:targetSdkVersion="14" />    <uses-permission android:name="android.permission.INTERNET"/>    <application        android:allowBackup="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity            android:name="edu.hbcit.testandroid.activity.MainActivity"            android:label="@string/app_name" >            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>        <activity            android:name="edu.hbcit.testandroid.activity.ResultActivity"            android:label="@string/title_activity_result" >        </activity>        <service android:name="edu.hbcit.testandroid.service.ConnectService">        </service>    </application></manifest>

6.重头戏Activity登场——需要注意的几个要点

1. 按钮监听事件中，使用Intent将要传递的值传给service。有点类似于Java Web中的session。
   
2. 接收广播类中，同样使用Intent将要传递的值传给下一个Activity。
3. 在onCreate()中，动态注册接收广播类的实例receiver。
4. 在接收广播类中，不要使用完毕后忘记注销接收器，否则会报一个Are you missing a call to unregisterReceiver()? 的异常。
   

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package edu.hbcit.testandroid.activity;import java.util.HashMap;import edu.hbcit.testandroid.R;import edu.hbcit.testandroid.R.id;import edu.hbcit.testandroid.R.layout;import edu.hbcit.testandroid.R.menu;import edu.hbcit.testandroid.service.ConnectService;import edu.hbcit.testandroid.util.DialogUtil;import edu.hbcit.testandroid.util.HttpUtil;import android.os.Bundle;import android.os.StrictMode;import android.app.Activity;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.util.Log;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;public class MainActivity extends Activity { private static final String ACTION_RECV_MSG = "edu.hbcit.testandroid.intent.action.RECEIVE_MESSAGE"; private MessageReceiver receiver ; EditText et_username ; EditText et_password;  @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //获取文本view        TextView tv = (TextView)findViewById(R.id.mainContent);        //获取输入框        et_username = (EditText)findViewById(R.id.userName);        et_password = (EditText)findViewById(R.id.password);        //获取按钮        Button submit = (Button)findViewById(R.id.myButton);        tv.setText("这是Hello World登录示例");        //http://192.168.1.101:8080/server/LoginServlet?un=aaa&pw=123456        //为按钮绑定事件监听器        submit.setOnClickListener(new OnClickListener(){         public void onClick(View v){          if (validate()){           // 如果登录成功           Intent msgIntent = new Intent(MainActivity.this, ConnectService.class);           msgIntent.putExtra("username", et_username.getText().toString().trim());           msgIntent.putExtra("password", et_password.getText().toString().trim());           startService(msgIntent);          }         }        });                //动态注册receiver          IntentFilter filter = new IntentFilter(ACTION_RECV_MSG);          filter.addCategory(Intent.CATEGORY_DEFAULT);          receiver = new MessageReceiver();          registerReceiver(receiver, filter);      }  // 对用户输入的用户名、密码进行校验   private boolean validate()   {    String username = et_username.getText().toString().trim();    if (username.equals(""))    {     DialogUtil.showDialog(this, "用户名是必填项！", false);     return false;    }    String pwd = et_password.getText().toString().trim();    if (pwd.equals(""))    {     DialogUtil.showDialog(this, "密码是必填项！", false);     return false;    }    return true;   }     //接收广播类      public class MessageReceiver extends BroadcastReceiver {          @Override          public void onReceive(Context context, Intent intent) {             String message = intent.getStringExtra("result");             Log.d("MessageReceiver", message);        // 如果登录成功   if (message.equals("true")){    // 启动Main Activity    Intent nextIntent = new Intent(MainActivity.this, ResultActivity.class);    startActivity(nextIntent);    // 结束该Activity    finish();    //注销广播接收器    context.unregisterReceiver(this);   }else{    DialogUtil.showDialog(MainActivity.this, "用户名称或者密码错误，请重新输入！", false);   }           }      }      }

运行效果：

1.登录界面

2.登录失败界面

3.登录成功界面

小李专栏原创文章，转自需注明出处【http://blog.csdn.net/softwave】。

           

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