简单的进行登录和签到的操作，程序编译后再2.3的系统下可以正常运行，但是无法在4.0的系统上运行，httpclient.execute方法出现错误进行跳出。
代码如下：

package com.vi88;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.http.HttpEntity;
import org.apache.http.HttpHost;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
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.conn.params.ConnRouteParams;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpParams;
import org.apache.http.protocol.HTTP;


import android.net.Proxy;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.support.v4.app.NavUtils;

public class Main extends Activity {
	private DefaultHttpClient httpclient;
	private String login_url="http://www.vi88.com/forum/member.php?mod=logging&action=login&loginsubmit=yes&infloat=yes&lssubmit=yes&inajax=1";
	private String sign_url="plugin.php?id=dsu_amupper:pper&ajax=1&formhash=";
	private String bbs_url="http://www.vi88.com/forum/forum.php";
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //获取代理信息 
        
        String host = Proxy.getDefaultHost();  
        int port = Proxy.getDefaultPort();  
        Log.d("", "[createHttpClient] proxyHost = " + host); 
        Log.d("", "[createHttpClient] proxyPort = " + port);
        //设置代理
        if(port!=-1){
        	HttpHost httpHost = new HttpHost(host, port);
            HttpParams httpParams = new BasicHttpParams();  
            httpParams.setParameter(ConnRouteParams.DEFAULT_PROXY, httpHost); 
            httpclient=new DefaultHttpClient(httpParams);
        }else{
        	httpclient=new DefaultHttpClient();
        }       
        //.0.post();
        login("123456789","123456789");
        String sign_url1=getsignurl();
        sign(sign_url1);
        
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    private void login(String username,String password){
    	HttpPost httppost = new HttpPost(login_url);
    	List<NameValuePair> parameters = new ArrayList<NameValuePair>();
    	parameters.add(new BasicNameValuePair("fastloginfield", "username"));
    	parameters.add(new BasicNameValuePair("handlekey", "ls"));
    	parameters.add(new BasicNameValuePair("password", password));
    	parameters.add(new BasicNameValuePair("quickforward", "yes"));
    	parameters.add(new BasicNameValuePair("username", username));
    	String result="";
    	int j=0;
    	while(!result.contains("欢迎您回来")&&j<5){
    		try {
            	UrlEncodedFormEntity uef = new UrlEncodedFormEntity(parameters, HTTP.UTF_8);
                httppost.setEntity(uef);
                result=get_post_result(httppost,httpclient); 
                
                Log.e("result", result);
                j++;
            } catch (Exception e) {
            	j++;
            }
    	}
    	
    	
    }
	private static String get_post_result(HttpPost httppost,DefaultHttpClient httpclient){
    	String result="";
    	BufferedReader in = null; 
    	HttpResponse response;
		try {
			response = httpclient.execute(httppost);
			
			
			in = new BufferedReader(new InputStreamReader(response.getEntity()  
	                .getContent(),"gbk"));  
	        StringBuffer sb = new StringBuffer("");  
	        String line = "";  
	        String NL = System.getProperty("line.separator"); 
	        while ((line = in.readLine()) != null) {  
	            sb.append(line + NL);  
	        }  
	        in.close();  
	        result = sb.toString(); 
	        
	        
		} catch (ClientProtocolException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			Log.e("ClientProtocolException", e.getMessage());
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			Log.e("IOException", e.getMessage());
		}  
        
        
    	return result;
    	
    }
	private String getsignurl(){
		String url="";
		HttpGet get = new HttpGet(bbs_url);
		String result="";
    	BufferedReader in = null; 
    	HttpResponse response;
		try {
            response = httpclient.execute(get);
            in = new BufferedReader(new InputStreamReader(response.getEntity()  
	                .getContent(),"gbk"));  
	        StringBuffer sb = new StringBuffer("");  
	        String line = "";  
	        String NL = System.getProperty("line.separator"); 
	        while ((line = in.readLine()) != null) {  
	            sb.append(line + NL);  
	        }  
	        in.close();  
	        result = sb.toString(); 
	        String regEx="plugin.php[?]{1}id=dsu_amupper:pper&ajax=1&formhash=[0-9|a-z]{8}";
	        Pattern p=Pattern.compile(regEx);  
	        Matcher m=p.matcher(result);
	        while(m.find()){
	        	url="http://www.vi88.com/forum/"+m.group().toString();
	        }
		} catch (Exception e) {
            //log.error(e);
		}
		return url;
	}
	public void sign(String sign_url1){
		HttpGet get = new HttpGet(sign_url1);
		String result="";
    	BufferedReader in = null; 
    	HttpResponse response;
		try {
            response = httpclient.execute(get);
            in = new BufferedReader(new InputStreamReader(response.getEntity()  
	                .getContent(),"gbk"));  
	        StringBuffer sb = new StringBuffer("");  
	        String line = "";  
	        String NL = System.getProperty("line.separator"); 
	        while ((line = in.readLine()) != null) {  
	            sb.append(line + NL);  
	        }  
	        in.close();  
	        result = sb.toString(); 
	        
		} catch (Exception e) {
            //log.error(e);
		}
	}
    
}