@Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.fragment_choose_main);
    listview = (ListView) findViewById(R.id.list_view);
    titleText = (TextView) findViewById(R.id.title_text);
    adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, dataList);
    listview.setAdapter(adapter);
    coolweatherdb = CoolWeatherDB.getInstance(this);
    // listview的点击事件
    listview.setOnItemClickListener(
        new OnItemClickListener() {

          @Override
          public void onItemClick(AdapterView<?> arg0, View view, int index, long arg3) {
            if (currentLevel == LEVEL_PROVINCE) {
              selectedprovince = provinceList.get(index);
              querycity();
            } else if (currentLevel == LEVEL_CITY) {
              selectedcity = cityList.get(index);
              querycounty();
            }
          }
        });
    queryprovince();
  }
 /*
  * 查询省内所有市,优先在数据库中查询,如果没有查询到再到服务器上去查询
  */
 private void querycity() {
   cityList = coolweatherdb.loadCities(selectedprovince.getId());
   if (cityList.size() > 0) {
     dataList.clear();
     for (City province : cityList) {
       dataList.add(province.getCityname());
     }
     adapter.notifyDataSetChanged();
     listview.setSelection(0);
     titleText.setText(selectedprovince.getProvincename());
     currentLevel = LEVEL_CITY;
   } else {
     queryFromServer(selectedprovince.getProvincecode(), "city");
   }
 }
 /*
  * 查询全国所有的省,优先在数据库中查询,如果没有查询到再到服务器上去查询
  */
 private void queryprovince() {
   provinceList = coolweatherdb.loadProvinces();
   if (provinceList.size() > 0) {
     dataList.clear();
     for (Province province : provinceList) {
       dataList.add(province.getProvincename());
     }
     adapter.notifyDataSetChanged();
     listview.setSelection(0);
     titleText.setText("中国");
     currentLevel = LEVEL_PROVINCE;
   } else {
     queryFromServer(null, "province");
   }
 }