handler异步

handler用于多线程

handler必须存在于主线程中

界面ui更新必须在handler中

对于异步，对于每一个任务我们都要创建一个线程

Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            String response = (String) msg.obj;
            Log.e("msg handler1", String.valueOf(msg.what));
            switch (msg.what) {
            case 1:
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                news_flag.setText(response);
                
                break;
            case 2:
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                meetings_flag.setText(response);
                
                break;
            
            }
        }
    };

private void loginPost(final String url, final String flag) {
        new Thread(new Runnable() {
            @Override
            public void run() {


                HttpClient client = new DefaultHttpClient();
                HttpPost post=new HttpPost(url);
                List<NameValuePair> params=new ArrayList<NameValuePair>();
                JSONObject obj= new JSONObject();
                try {
                    obj.put("flag", flag);
                } catch (JSONException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
                params.add(new BasicNameValuePair("num",obj.toString()));
                
                try {
                    post.setEntity(new UrlEncodedFormEntity(params,HTTP.UTF_8));
                    HttpResponse response = client.execute(post);
                    // 判断请求是否成功
                    if (response.getStatusLine().getStatusCode() == 200) {
                        HttpEntity entity = response.getEntity();

                        String out;
                        if (entity != null) {
                            out = EntityUtils.toString(entity, "utf-8");
                            
                            JSONObject json=null;
                            try {
                        
                                json=new JSONObject(out);
                        
                            } catch (JSONException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                            }
                            // 在子线程中将Message对象发出去
                            Message message = new Message();
                            
                                try {
                                    Log.e("1.........",json.getString("flag") );
                                    if(json.getString("flag").equals("news")){
                                    message.what = 1;
                                    message.obj=json.getString("value");
                                    handler.sendMessage(message);
                                    }else if(json.getString("flag").equals("meetings")){
                                        
                                        message.what = 2;// 请求的地址是访问会议资讯地址
                                        message.obj=json.getString("value");
                                        handler.sendMessage(message);
                                    }
                                } catch (JSONException e) {
                                    // TODO Auto-generated catch block
                                    e.printStackTrace();
                                    
                                }// 请求的地址是访问新闻资讯地址
                                
                            
                        } 
                    } 
                } catch (ClientProtocolException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }}).start();
    }
    

public void onResume() {
        // TODO Auto-generated method stub
        super.onResume();
        loginPost(url+"/news", "news");
        loginPost(url+"/meetings", "meetings");
    }