多重值測試，如何替換許多其他if語句？

Question

在我的android應用程序中，我測試了一些字符串（我從另一個活動中獲取）以查看它們是否爲空。如果沒有，我建我的網址，從這些值，例如：（編者）

//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... 

我不知道我怎樣才能提高這些測試的部分，感謝您的幫助！

Answer 1

類似這樣寫的東西

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 " : "");