问题描述

android 多个Handler问题

新手入门求各位大牛指教。
在做一个应用时，要汇总多个数据库里的数据，因此用了多个Handler请求数据，获取到所有数据后再汇总。现在问题是怎样才能知道所有数据都请求到了？代码如下 ：

for (BranchVO m : response.getData()) {
                if(!m.isIsGroup())
                ResponseBusingessEarningData(sDate,m.getBranchID(),URL);
            }

    /*
     * 请求营业统计数据
     */
    private void ResponseBusingessEarningData(String Date,String BranchID,String URL){
        //封装传递参数的集合
        String str="[u4e00-u9fa5]";
        String localDate = Date.replaceAll(str, "-").substring(0,10);
        List<NameValuePair> parameters = new ArrayList<NameValuePair>();
        parameters.add(new BasicNameValuePair("Date",localDate));
        parameters.add(new BasicNameValuePair("BranchID",BranchID));
        HttpConnectionUtil.getResponseByPost(URL, "BusinessEarning",parameters, beHandler,(BaseActivity)myContext);
    }

    ResponseHandler beHandler = new ResponseHandler(){

        @Override
        protected void handleResponse(Message msg) {
            String responseText = (String) msg.getData().get("responseText");
            Gson gson = new Gson();
            ApiResultModel<BusinessEarningVO> response = gson.fromJson(responseText,new TypeToken<ApiResultModel<BusinessEarningVO>>(){}.getType());
            if(response.getData() != null && response.getData().size() > 0){
                for (BusinessEarningVO vo : response.getData()) {
                    beList.add(vo);
                }
                beAdapter.notifyDataSetChanged();
            }

            //dismissDialog();
        }

    };

解决方案

CountDownLatch，类似下面这样

CountDownLatch latch=new CountDownLatch( response.getData()的数量)
 for (BranchVO m : response.getData()) {
                if(!m.isIsGroup()){
                  ResponseBusingessEarningData(sDate,m.getBranchID(),URL);
                                    }else{
                                       latch.countDown();//这里，不用获取数据down一次
                                    }
            }

    /*
     * 请求营业统计数据
     */
    private void ResponseBusingessEarningData(String Date,String BranchID,String URL){
        //封装传递参数的集合
        String str="[u4e00-u9fa5]";
        String localDate = Date.replaceAll(str, "-").substring(0,10);
        List<NameValuePair> parameters = new ArrayList<NameValuePair>();
        parameters.add(new BasicNameValuePair("Date",localDate));
        parameters.add(new BasicNameValuePair("BranchID",BranchID));
        HttpConnectionUtil.getResponseByPost(URL, "BusinessEarning",parameters, beHandler,(BaseActivity)myContext);
    }

    ResponseHandler beHandler = new ResponseHandler(){

        @Override
        protected void handleResponse(Message msg) {
            String responseText = (String) msg.getData().get("responseText");
            Gson gson = new Gson();
            ApiResultModel<BusinessEarningVO> response = gson.fromJson(responseText,new TypeToken<ApiResultModel<BusinessEarningVO>>(){}.getType());
            if(response.getData() != null && response.getData().size() > 0){
                for (BusinessEarningVO vo : response.getData()) {
                    beList.add(vo);
                }
                beAdapter.notifyDataSetChanged();
            }
            latch.countDown();//这里，完成一个down一次
            //dismissDialog();
        }

    };

解决方案二：

简单来说就是将每个数据库对应的一个变量（自己加），然后初始化为false，处理一个置一个true，并且在置true的下一句可以去判断是否全部置为true了