XML 데이터 구문 분석이 예기치 않게 실패합니다.

Question

현재 XML을 동적으로 사용하여 데이터를 구문 분석하려고합니다. 그래서 다른 태그를 통해 데이터를 검색하고 SimpleAdapter를 사용하여 다른 textviews에 삽입하려고합니다. 그러나 그것이 나의 관점에서 실패 할 때, 그것은 일하기로되어있다. 이 점을 이해하도록 도와주세요.

이 내 SearchResults.java입니다 :

public class SearchResult extends ListActivity{ 

String set_number; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.list); 

    ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>(); 

    //retrieve text passed from previous activity 
    Bundle bundle = getIntent().getExtras(); 
    String searchItems = bundle.getString("searchItems"); 

    //get the xml data using retrieve text from previous activity  
    String xmlSetNo = XMLFunctions.getSetNoXML(searchItems); 
    Document docSetNo = XMLFunctions.XMLfromString(xmlSetNo);//change xml data to doc format 

    NodeList nodeSetNo = docSetNo.getElementsByTagName("find"); 

    for (int i = 0; i < nodeSetNo.getLength(); i++) {       
     Element e = (Element)nodeSetNo.item(i); 
     set_number = XMLFunctions.getValue(e, "set_number"); 
    }  

    String xmlRecords = XMLFunctions.getRecordsXML(set_number); 
    Document docRecords = XMLFunctions.XMLfromString(xmlRecords); 

    NodeList nodeRecords = docRecords.getElementsByTagName("metadata"); 

    for(int i = 0; i < nodeRecords.getLength(); i++) { 
     HashMap<String, String> map = new HashMap<String, String>();  

     Element e = (Element)nodeRecords.item(i); 

     //map.put("cover_image", getTagValue("varfield id='20'", e)); 
     map.put("title", getTagValue("varfield id='245'", e)); 
     map.put("author", getTagValue("varfield id='100'", e)); 
     map.put("format", getTagValue("fixfield id='FMT'", e)); 
     map.put("call_number", getTagValue("varfield id='099'", e)); 
     /* 
     map.put("set_number", XMLFunctions.getValue(e, "set_number")); 
     map.put("no_records", "No. of Records:" + XMLFunctions.getValue(e, "no_records")); 
     map.put("no_entries", "No. of Entries: " + XMLFunctions.getValue(e, "no_entries")); 
     mylist.add(map); 
     */ 
    } 

    ListAdapter adapter = new SimpleAdapter(this, mylist , R.layout.search_result_display_list, 
        new String[] { "cover_image","title","author","format","call_number"}, 
        new int[] {R.id.cover_image, R.id.item_title, R.id.item_author,R.id.item_format,R.id.item_call_number }); 

    setListAdapter(adapter); 

    final ListView lv = getListView(); 
    lv.setTextFilterEnabled(true); 
    /*lv.setOnItemClickListener(new OnItemClickListener() { 
     public void onItemClick(AdapterView<?> parent, View view, int position, long id) {    
      @SuppressWarnings("unchecked") 
      HashMap<String, String> o = (HashMap<String, String>) lv.getItemAtPosition(position);     
      Toast.makeText(SearchResult.this, "ID '" + o.get("id") + "' was clicked.", Toast.LENGTH_LONG).show(); 

     } 
    });*/ 
} 

private static String getTagValue(String sTag, Element eElement){ 
     NodeList nlList= eElement.getElementsByTagName(sTag).item(0).getChildNodes(); 
     Node nValue = (Node) nlList.item(0); 

     return nValue.getNodeValue();  
    } 
} 

이 내 XMLFunctions.java 내 XML 데이터 분석입니다 :

public class XMLFunctions { 

public final static Document XMLfromString(String xml){ 

    Document doc = null; 

    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); 
    try { 

     DocumentBuilder db = dbf.newDocumentBuilder(); 

     InputSource is = new InputSource(); 
     is.setCharacterStream(new StringReader(xml)); 
     doc = db.parse(is); 

    } catch (ParserConfigurationException e) { 
     System.out.println("XML parse error: " + e.getMessage()); 
     return null; 
    } catch (SAXException e) { 
     System.out.println("Wrong XML file structure: " + e.getMessage()); 
     return null; 
    } catch (IOException e) { 
     System.out.println("I/O exeption: " + e.getMessage()); 
     return null; 
    } 

    return doc; 

} 

/** Returns element value 
    * @param elem element (it is XML tag) 
    * @return Element value otherwise empty String 
    */ 
public final static String getElementValue(Node elem) { 
    Node kid; 
    if(elem != null){ 
     if (elem.hasChildNodes()){ 
      for(kid = elem.getFirstChild(); kid != null; kid = kid.getNextSibling()){ 
       if(kid.getNodeType() == Node.TEXT_NODE ){ 
        return kid.getNodeValue(); 
       } 
      } 
     } 
    } 
    return ""; 
} 

public static String getSetNoXML(String searchItems){ 
     String line = null; 

     try { 

      DefaultHttpClient httpClient = new DefaultHttpClient(); 
      //request for item's set_number 
      HttpGet requestSetNumber = new HttpGet("http://spark.opac.tp.edu.sg/X?op=find&scan_code=find_wrd&request="+ searchItems +"&base=tpl01"); 

      HttpResponse httpResponse = httpClient.execute(requestSetNumber); 
      HttpEntity httpEntity = httpResponse.getEntity(); 
      line = EntityUtils.toString(httpEntity); 

     } catch (UnsupportedEncodingException e) { 
      line = "<find status=\"error\"><msg>Can't connect to server</msg></find>"; 
     } catch (MalformedURLException e) { 
      line = "<find status=\"error\"><msg>Can't connect to server</msg></find>"; 
     } catch (IOException e) { 
      line = "<find status=\"error\"><msg>Can't connect to server</msg></find>"; 
     } 
     return line; 
} 

public static String getRecordsXML(String setNumber){ 
     String line = null; 

     try { 

      DefaultHttpClient httpClient = new DefaultHttpClient(); 
      //request records via set_number 
      HttpGet requestRecords = new HttpGet("http://spark.opac.tp.edu.sg/X?op=present&set_no="+ setNumber +"&set_entry=000000001,000000002,000000003," + 
        "000000004,000000005,000000006,000000007,000000008,000000009,000000010&format=marc"); 


      HttpResponse httpResponse = httpClient.execute(requestRecords); 
      HttpEntity httpEntity = httpResponse.getEntity(); 
      line = EntityUtils.toString(httpEntity); 

     } catch (UnsupportedEncodingException e) { 
      line = "<find status=\"error\"><msg>Can't connect to server</msg></find>"; 
     } catch (MalformedURLException e) { 
      line = "<find status=\"error\"><msg>Can't connect to server</msg></find>"; 
     } catch (IOException e) { 
      line = "<find status=\"error\"><msg>Can't connect to server</msg></find>"; 
     } 
     return line; 
} 

public static int numResults(Document doc){  
    Node results = doc.getDocumentElement(); 
    int res = -1; 

    try{ 
     res = Integer.valueOf(results.getAttributes().getNamedItem("find").getNodeValue()); 
    }catch(Exception e){ 
     res = -1; 
    } 

    return res; 
} 

public static String getValue(Element item, String str) {  
    NodeList n = item.getElementsByTagName(str);   
    return XMLFunctions.getElementValue(n.item(0)); 
} 
} 

마지막을,이 의 출력입니다 LogCat :

04-25 10 : 20 : 15.932 : ERROR/AndroidRuntime (418) : 치명적인 예외 : 주
04-25 10 : 20 : 15.932 : ERROR/AndroidRuntime (418) : java.lang.RuntimeException : 활동을 시작할 수 없습니다. ComponentInfo {joel.TPLibrary/joel.TPLibrary.SearchResult} : java.lang.NullPointerException
04-25 10:20:15.932 : ERROR/AndroidRuntime (418) : android.app.ActivityThread.performLaunchActivity (ActivityThread.java:2663))
10월 4일부터 25일까지 : 20 : 15.932 : ERROR/AndroidRuntime (418) : 20 :
10월 4일에서 25일까지 android.app.ActivityThread.handleLaunchActivity (ActivityThread.java:2679)로 15.932 : ERROR/AndroidRuntime (418) : android.app.ActivityThread.access $ 2300 (ActivityThread.java:125)
04-25 10 : 20 : 15.932 : ERROR/그리고 roidRuntime (418) : android.app.ActivityThread $ H.handleMessage (ActivityThread.java:2033)
04-25 10 : 20 : 15.932 : ERROR/AndroidRuntime (418) : android.os.Handler.dispatchMessage (Handler .java : 99)
04-25 10 : 20 : 15.932 : ERROR/AndroidRuntime (418) : android.os.Looper.loop (Looper.java:123)
04-25 10 : 20 : 15.932 : ERROR/AndroidRuntime (418) : android.app.ActivityThread.main (ActivityThread.java:4627)
04-25 10 : 20 : 15.932 : ERROR/AndroidRuntime (418) : java.lang.reflect.Method.invokeNative에서 네이티브 메소드)
04-25 10 : 20 : 15.932 : ERROR/AndroidRuntime (418) : java.lang.reflect.Method.invoke (Method.java:521)
04-25 10 : 20 : 15.932 : ERROR/AndroidRun 시간 (418) : com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run (ZygoteInit.java:868)
04-25 10 : 20 : 15.932 : ERROR/AndroidRuntime (418) : com.android.internal .os.ZygoteInit.main (ZygoteInit.java:626) 04-25 10 : 20 : 15.932 : ERROR/AndroidRuntime (418) : at dalvik.system.NativeStart.main (기본 메소드)
04-25 10:20 : 15.932 : ERROR/AndroidRuntime (418) : 원인 : java.lang.NullPointerException 04-25 10 : 20 : 15.932 : ERROR/AndroidRuntime (418) : joel.TPLibrary.SearchResult.getTagValue (SearchResult.java:89))
04-25 10:20:15.932 : ERROR/AndroidRuntime (418) : joel.TPLibrary.SearchResult.onCreate (SearchResult.java:58)
04-25 10 : 20 : 15.9 32 : ERROR/AndroidRuntime (418) : android.app.Instrumentation.callActivityOnCreate (Instrumentation.java:1047)
04-25 10 : 20 : 15.932 : ERROR/AndroidRuntime (418) : android.app.ActivityThread.performLaunchActivity (ActivityThread.java:2627)
04-25 10 : 20 : 15.932 : ERROR/AndroidRuntime (418) : ...11 이상

Answer 1

나는 안드로이드에서 XML을 구문 분석하려고한다고 생각합니다. 솔직히 코드는 필요 이상으로 복잡해 보입니다.

대신 XML을 쉽게 작성하고 출력하는 데 도움이되는 Simple이라는 주석 기반 XML 프레임 워크를 사용하는 것이 좋습니다. 그럴만 한 이유는 I even wrote a blog post about how to include it in your Android projects입니다.

몇 가지 예제 XML을 제공하면 잘못된 정보에 대한 정보를 더 많이 제공 할 수 있습니다.