public class MainActivity extends TabActivity{
    private TabHost tabHost;

    private static final String HOME_TAB="home"; 
    private static final String AT_TAB="at"; 
    private static final String MSG_TAB="msg"; 
    private static final String MORE_TAB="more"; 

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        tabHost = this.getTabHost();
        TabSpec homeSpec=tabHost.newTabSpec(HOME_TAB).setIndicator(HOME_TAB).setContent(new Intent(this,HomeActivity.class));
        TabSpec atSpec=tabHost.newTabSpec(AT_TAB).setIndicator(AT_TAB).setContent(new Intent(this,AtActivity.class));
        TabSpec msgSpec=tabHost.newTabSpec(MSG_TAB).setIndicator(MSG_TAB).setContent(new Intent(this,MsgActivity.class));
        TabSpec moreSpec=tabHost.newTabSpec(MORE_TAB).setIndicator(MORE_TAB).setContent(new Intent(this,MoreActivity.class));

        tabHost.addTab(homeSpec);
        tabHost.addTab(atSpec);
        tabHost.addTab(msgSpec);
        tabHost.addTab(moreSpec);

        tabHost.setCurrentTabByTag(HOME_TAB);

        RadioGroup radioGroup =  (RadioGroup) this.findViewById(R.id.main_radio);
        final RadioButton rb=(RadioButton)this.findViewById(R.id.rb_home);
        rb.setBackgroundResource(R.drawable.tabhost_press);

        radioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener()
        {
            public void onCheckedChanged(RadioGroup group, int checkedId)
            {
                rb.setBackgroundResource(R.drawable.tabhost_bg_selector);
                switch (checkedId)
                {
                    case R.id.rb_home:
                        tabHost.setCurrentTabByTag(HOME_TAB);
                        break;

                    case R.id.rb_at:
                        tabHost.setCurrentTabByTag(AT_TAB);
                        break;

                    case R.id.rb_mess:
                        tabHost.setCurrentTabByTag(MSG_TAB);
                        break;

                    case R.id.rb_more:
                        tabHost.setCurrentTabByTag(MORE_TAB);
                        break;

                    default:
                        break;
                }
            }
        });

    }
}

<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@android:id/tabhost"<!--注意这里 -->
    android:background="#ffffff"
    >
    <TabWidget
         android:id="@android:id/tabs"<!--注意这里 -->
          android:layout_width="fill_parent"
         android:layout_height="wrap_content" 
         android:visibility="gone"/>
    <FrameLayout
         android:id="@android:id/tabcontent"<!--注意这里 -->
         android:layout_width="fill_parent"
         android:layout_height="fill_parent"/>
    <RadioGroup
        android:id="@+id/main_radio"
        android:layout_width="fill_parent"
        android:layout_height="48dp"
        android:layout_gravity="bottom"
        android:orientation="horizontal"
        android:background="@drawable/bar" >
        <RadioButton
            android:id="@+id/rb_home"
            android:drawableTop="@drawable/home_icon"
            style="@style/rg_style"
            android:text="主页" />
        <RadioButton
            android:id="@+id/rb_at"
            android:drawableTop="@drawable/at_icon"
            style="@style/rg_style"
            android:text="我" />
        <RadioButton
            android:id="@+id/rb_mess"
            android:drawableTop="@drawable/msg_icon"      
            style="@style/rg_style"
            android:text="消息" />
        <RadioButton
            android:id="@+id/rb_more"      
            android:drawableTop="@drawable/more_icon"
            style="@style/rg_style"
            android:text="更多" />                
    </RadioGroup>
</TabHost>

package com.fangjie.weibo.util;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.List;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import com.fangjie.weibo.bean.User;
import com.fangjie.weibo.bean.Weibo;
public class WeiboUtil {

    public List<Weibo> getWeiboList(String token, long i) {
        List<Weibo> weibos=new ArrayList<Weibo>();
        String url="https://api.weibo.com/2/statuses/home_timeline.json";
        String params="access_token="+token+"&max_id="+i;
        String result=HttpRequest(1, url, params);
        try {
            JSONObject json_res=new JSONObject(result);
            JSONArray json_weibos=json_res.getJSONArray("statuses");
            for(int j=0;j<json_weibos.length();j++)
            {
                Weibo weibo=new Weibo();
                JSONObject json_weibo=json_weibos.getJSONObject(j);
                weibo.setComments_count(json_weibo.getInt("comments_count"));
                weibo.setContent(json_weibo.getString("text"));
                weibo.setFrom(json_weibo.getString("source"));
                weibo.setReposts_count(json_weibo.getInt("reposts_count"));
                weibo.setTime(json_weibo.getString("created_at"));
                weibo.setWid(json_weibo.getLong("id"));

                User user=new User();
                JSONObject json_user=json_weibo.getJSONObject("user");
                user.setUid(json_user.getLong("id"));
                user.setName(json_user.getString("screen_name"));
                user.setProfile_image_url(json_user.getString("profile_image_url"));
                user.setIsv(json_user.getBoolean("verified"));
                weibo.setUser(user);

                if(!json_weibo.isNull("thumbnail_pic"))
                    weibo.setBmiddle_pic(json_weibo.getString("thumbnail_pic"));
                else
                    weibo.setBmiddle_pic("");

                if(!json_weibo.isNull("retweeted_status"))
                {
                    Weibo zweibo=new Weibo();

                    JSONObject json_zweibo=json_weibo.getJSONObject("retweeted_status");
                    zweibo.setComments_count(json_zweibo.getInt("comments_count"));
                    zweibo.setContent(json_zweibo.getString("text"));
                    zweibo.setFrom(json_zweibo.getString("source"));
                    zweibo.setReposts_count(json_zweibo.getInt("reposts_count"));
                    zweibo.setTime(json_zweibo.getString("created_at"));
                    zweibo.setWid(json_zweibo.getLong("id"));

                    User zuser=new User();
                    JSONObject json_zuser=json_zweibo.getJSONObject("user");
                    zuser.setUid(json_zuser.getLong("id"));
                    zuser.setName(json_zuser.getString("screen_name"));
                    zuser.setProfile_image_url(json_zuser.getString("profile_image_url"));
                    zuser.setIsv(json_zuser.getBoolean("verified"));
                    zweibo.setUser(zuser);

                    if(!json_zweibo.isNull("thumbnail_pic"))
                        zweibo.setBmiddle_pic(json_zweibo.getString("thumbnail_pic"));
                    else
                        zweibo.setBmiddle_pic("");

                    weibo.setWeibo(zweibo);
                }
                else
                {
                    weibo.setWeibo(null);
                }
                weibos.add(weibo);
                System.out.println(weibo.content);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return weibos;
    }

    //HTTP请求   way-0 Post   way-1  Get
    public static String HttpRequest(int way,String url,String params)
    {
        String result = "";
        BufferedReader in = null;
        PrintWriter out = null;
        try {
            String urlNameString = url + "?" + params;
            System.out.println(urlNameString);
            URL realUrl = new URL(urlNameString);
            URLConnection connection;
            if(way==0)
            {
                // 打开和URL之间的连接
                connection= realUrl.openConnection();
                // 发送POST请求必须设置如下两行
                connection.setDoOutput(true);
                connection.setDoInput(true);
                // 获取URLConnection对象对应的输出流
                out = new PrintWriter(connection.getOutputStream());
                // 发送请求参数
                out.print(params);
                // flush输出流的缓冲
                out.flush();                
            }
            else
            {
                // 打开和URL之间的连接
                connection = realUrl.openConnection();
                // 设置通用的请求属性
                connection.setRequestProperty("accept", "*/*");
                connection.setRequestProperty("connection", "Keep-Alive");
                connection.setRequestProperty("user-agent",
                        "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
                // 建立实际的连接
                //connection.connect();
            }
            // 定义 BufferedReader输入流来读取URL的响应
            in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            System.out.println("发送GET请求出现异常！" + e);
            e.printStackTrace();
        }
        // 使用finally块来关闭输入流
        finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return result;
    }
}