在黑莓xml解析中的空節點處顯示消息

Question

解析黑莓應用程序中的XML結果，該應用程序返回表單中的節點;

<searches> 
<search id ='1234'> 
<name> somename </name> 
<address> some address </address> 
<sector> some sector </sector> 
<contacts> 12345, me@me.com </contacts> 
<searches>  

當搜索沒有任何匹配時返回空結果，也就是說;

<name></name> 
<address></address> 
<sector></sector> 
<contacts></contacts> 

不返回結果。它看起來就像<searches></searches>。在搜索結果返回時，如何指定對話框警報<searches></searches>

這裏是我的Http連接附帶的解析器。

try{ 
     HttpConnection connection = (HttpConnection)Connector.open("http://someurl.xml",Connector.READ_WRITE); 
     URLEncodedPostData postData = new URLEncodedPostData(URLEncodedPostData.DEFAULT_CHARSET, false); 
     postData.append("username", "someusername"); 
     postData.append("password", "somepassword"); 
     postData.append("term", word); 
     connection.setRequestMethod(HttpConnection.POST); 
     connection.setRequestProperty("Content-Type","application/x-www-form-urlencoded"); 
     connection.setRequestProperty("User-Agent","Profile/MIDP-2.0 Configuration/CLDC-1.0"); 
     OutputStream requestOut = connection.openOutputStream(); 
     requestOut.write(postData.getBytes()); 
     connection.getHeaderField("Content-type"); 
     DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance(); 
     DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder(); 
     docBuilder.isValidating(); 
     InputStream detailIn = connection.openInputStream(); 
     doc = docBuilder.parse(detailIn); 
     requestOut.close(); 
     connection.close(); 
     NodeList list = doc.getElementsByTagName("name"); 
     NodeList list1 = doc.getElementsByTagName("address"); 
     NodeList list2 = doc.getElementsByTagName("sector"); 
     NodeList list3 = doc.getElementsByTagName("contacts"); 
     callback(list,list1,list2,list3); 
     requestOut.close(); 
     connection.close(); 
    } 
    catch(Exception ex){ 
     System.out.println(ex.toString()); 
    } 

是否使用if或for？

Answer 1

我沒有在我面前（所以我不能對此進行測試代碼）的Eclipse插件，但這樣的事情應該工作：

doc = docBuilder.parse(detailIn); 
requestOut.close(); 
connection.close(); 
NodeList list = doc.getElementsByTagName("name"); 
NodeList list1 = doc.getElementsByTagName("address"); 
NodeList list2 = doc.getElementsByTagName("sector"); 
NodeList list3 = doc.getElementsByTagName("contacts"); 
if (list == null || list.getLength() == 0) { 
    // no results, so post an alert on the UI thread 
    UiApplication.getUiApplication().invokeLater(new Runnable() { 
     public void run() { 
      Dialog.alert("No results found!"); 
     } 
    }); 
} 

這只是測試存在name元素，假設如果name丟失，其他人（地址，扇區和聯繫人）也將丟失。如果這不適用於您的應用程序，則可以選擇使if語句也檢查list1，list2和list3。