AsyncTast异步线程使用

1.定义AsyncTast类

//AsyncTask<excute的参数,更新progress的参数,doinBackground返回的结果>
    class loadNewsAsyncTask extends AsyncTask<String, Void, List<NewsBean>>{
        //预加载
        @Override
        protected void onPreExecute() {
            // TODO Auto-generated method stub
            super.onPreExecute();
        }
        //真正的异步线程-用于读取，加载，转换等耗时操作（其他方法都属于主线程，主线程才可以更新UI）
        @Override
        protected List<NewsBean> doInBackground(String... params) {
            // TODO Auto-generated method stub
            List<NewsBean> list=getJsonData(params[0]);
            return list;
        }
        //更新进度，通常在doInBackground中调用publishProgress(values);更新
        @Override
        protected void onProgressUpdate(Void... values) {
            // TODO Auto-generated method stub
            super.onProgressUpdate(values);
        }
        //doInBackground结束后自动调用
        @Override
        protected void onPostExecute(List<NewsBean> result) {
            // TODO Auto-generated method stub
            super.onPostExecute(result);
            adapter=new NewsAdapter(MainActivity.this, result);
            listView.setAdapter(adapter);
        }
    }

2.执行AsyncTast线程

loadNewsAsyncTask tast=new loadNewsAsyncTask();
tast.execute(url);