多重值测试，如何替换许多其他if语句？

Question

在我的android应用程序中，我测试了一些字符串（我从另一个活动中获取）以查看它们是否为空。如果没有，我建我的网址，从这些值，例如：（编者）

//country only 
    if (!fetchData_country.isEmpty() && fetchData_city.isEmpty() && fetchData_pmin.isEmpty() && fetchData_pmax.isEmpty()){ 
     query_url = URL_PRODUCT + "?" + URL_SEARCH_COUNTRY + id_country + URL_LANGUAGE; 
     Log.i("INFO", "Url country only : " + query_url); 
    } 
    //country & price min 
    else if(!fetchData_country.isEmpty() && fetchData_city.isEmpty() && !fetchData_pmin.isEmpty() && fetchData_pmax.isEmpty()) { 
     query_url = URL_PRODUCT + "?" + URL_SEARCH_COUNTRY + id_country + "&" + URL_SEARCH_PRICE_MIN + id_pmin + URL_LANGUAGE; 
     Log.i("INFO", "Url country & price_min : " + query_url); 
    } 

    //city & price_min 
    else if(fetchData_country.isEmpty() && !fetchData_city.isEmpty() && !fetchData_pmin.isEmpty() && fetchData_pmax.isEmpty()) { 
     query_url = URL_PRODUCT + "?" + URL_SEARCH_CITY + id_city + "&" + URL_SEARCH_PRICE_MIN + id_pmin + URL_LANGUAGE; 
     Log.i("INFO", "Url city & price_min : " + query_url); 
    } 

    // country & city & pmin 
    else if(!fetchData_country.isEmpty() && !fetchData_city.isEmpty() && !fetchData_pmin.isEmpty() && fetchData_pmax.isEmpty()) { 
     query_url = URL_PRODUCT + "?" + URL_SEARCH_COUNTRY + id_country + "&" + URL_SEARCH_CITY + id_city + "&" + URL_SEARCH_PRICE_MIN + id_pmin + URL_LANGUAGE; 
     Log.i("INFO", "Url country & city & pmin : " + query_url); 
    }//many values to test still... 

我不知道我怎样才能提高这些测试的部分，感谢您的帮助！

Answer 1

类似这样写的东西

String query_url = URL_PRODUCT + "?" + (!fetchData_country.isEmpty() ? "URL_SEARCH_COUNTRY + id_country " : "") 
      +(!fetchData_country.isEmpty() ? "&":"")+ (!fetchData_pmin.isEmpty() ? " + URL_SEARCH_PRICE_MIN + id_pmin " : "") 
      +(!fetchData_pmin.isEmpty() ? "&":"")+ (!fetchData_city.isEmpty() ? " + URL_SEARCH_CITY + id_city " : "");