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  3. Google 알림 피드에서 구문 분석하려고 할 때 java.lang.NullPointerException 오류가 발생합니다.

Google 알림 피드에서 구문 분석하려고 할 때 java.lang.NullPointerException 오류가 발생합니다.

2014-10-13 4 views
0

Google Alerts Source에서 이미 Android RSS Feed 앱을 만들었습니다. 컴파일 된 후 빈 화면 만 표시하고 충돌은 발생하지 않습니다. rss_item_list.xmlGoogle 알림 피드에서 구문 분석하려고 할 때 java.lang.NullPointerException 오류가 발생합니다.

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:orientation="vertical" 
    android:background="#ffffff"> 

    <!-- Header --> 
    <include layout="@layout/header"/> 

    <ListView 
     android:id="@android:id/list" 
     android:layout_below="@id/layoutHeader" 
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content" 
     android:divider="#bababa" 
     android:dividerHeight="1dp" 
     android:listSelector="@drawable/list_selector" 
     android:background="#ffffff" 
     android:cacheColorHint="#00000000"/> 

</RelativeLayout>

에서 RSSParser.java

import android.text.Html; 
import android.text.Spanned; 
import android.util.Log; 
import java.io.IOException; 
import java.io.StringReader; 
import java.io.UnsupportedEncodingException; 
import java.text.ParseException; 
import java.text.SimpleDateFormat; 
import java.util.ArrayList; 
import java.util.Date; 
import java.util.List; 
import javax.xml.parsers.DocumentBuilder; 
import javax.xml.parsers.DocumentBuilderFactory; 
import javax.xml.parsers.ParserConfigurationException; 
import org.apache.http.HttpResponse; 
import org.apache.http.client.ClientProtocolException; 
import org.apache.http.client.methods.HttpGet; 
import org.apache.http.impl.client.DefaultHttpClient; 
import org.apache.http.util.EntityUtils; 
import org.w3c.dom.Document; 
import org.w3c.dom.Element; 
import org.w3c.dom.Node; 
import org.w3c.dom.NodeList; 
import org.xml.sax.InputSource; 
import org.xml.sax.SAXException; 

public class RSSParser 
{ 
    private static String TAG_CHANNEL = "channel"; 
    private static String TAG_DESRIPTION; 
    private static String TAG_GUID; 
    private static String TAG_ITEM; 
    private static String TAG_LANGUAGE; 
    private static String TAG_LINK; 
    private static String TAG_PUB_DATE; 
    private static String TAG_TITLE = "title"; 

    static 
    { 
    TAG_LINK = "link"; 
    TAG_DESRIPTION = "content"; 
    TAG_LANGUAGE = "language"; 
    TAG_ITEM = "entry"; 
    TAG_PUB_DATE = "published"; 
    TAG_GUID = "guid"; 
    } 

    private String setTime(String paramString) 
    { 
    String str1 = paramString.substring(0, 10) + " " + paramString.substring(11, 19); 
    Log.d("date", str1); 
    SimpleDateFormat localSimpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 
    try 
    { 
     String str2 = localSimpleDateFormat.format(new Date(25200000L + localSimpleDateFormat.parse(str1).getTime())); 
     return str2; 
    } 
    catch (ParseException localParseException) 
    { 
     localParseException.printStackTrace(); 
    } 
    return str1; 
    } 

    public Document getDomElement(String paramString) 
    { 
    DocumentBuilderFactory localDocumentBuilderFactory = DocumentBuilderFactory.newInstance(); 
    try 
    { 
     DocumentBuilder localDocumentBuilder = localDocumentBuilderFactory.newDocumentBuilder(); 
     InputSource localInputSource = new InputSource(); 
     localInputSource.setCharacterStream(new StringReader(paramString)); 
     Document localDocument = localDocumentBuilder.parse(localInputSource); 
     return localDocument; 
    } 
    catch (ParserConfigurationException localParserConfigurationException) 
    { 
     Log.e("Error: ", localParserConfigurationException.getMessage()); 
     return null; 
    } 
    catch (SAXException localSAXException) 
    { 
     Log.e("Error: ", localSAXException.getMessage()); 
     return null; 
    } 
    catch (IOException localIOException) 
    { 
     Log.e("Error: ", localIOException.getMessage()); 
    } 
    return null; 
    } 

    public final String getElementValue(Node paramNode) 
    { 
    if ((paramNode != null) && (paramNode.hasChildNodes())); 
    for (Node localNode = paramNode.getFirstChild(); ; localNode = localNode.getNextSibling()) 
    { 
     if (localNode == null) 
     return ""; 
     if ((localNode.getNodeType() == 3) || (localNode.getNodeType() == 4)) 
     return localNode.getNodeValue(); 
    } 
    } 

    public RSSFeed getRSSFeed(String paramString) 
    { 
    if (paramString != null) 
    { 
     String str1 = getXmlFromUrl(paramString); 
     if (str1 != null) 
     try 
     { 
      Element localElement = (Element)getDomElement(str1).getElementsByTagName(TAG_CHANNEL).item(0); 
      String str2 = getValue(localElement, TAG_TITLE); 
      String str3 = getValue(localElement, TAG_LINK); 
      RSSFeed localRSSFeed = new RSSFeed(str2, getValue(localElement, TAG_DESRIPTION), str3, paramString, getValue(localElement, TAG_LANGUAGE)); 
      return localRSSFeed; 
     } 
     catch (Exception localException) 
     { 
      localException.printStackTrace(); 
     } 
    } 
    return null; 
    } 

    public List<RSSItem> getRSSFeedItems(String paramString) 
    { 
    ArrayList localArrayList = new ArrayList(); 
    String str1 = getXmlFromUrl(paramString); 
    if (str1 != null) 
     try 
     { 
     NodeList localNodeList1 = getDomElement(str1).getElementsByTagName(TAG_ITEM); 
     for (int i = 0; ; i++) 
     { 
      if (i >= localNodeList1.getLength()) 
      return localArrayList; 
      Element localElement = (Element)localNodeList1.item(i); 
      String str2 = Html.fromHtml(getValue(localElement, TAG_TITLE)).toString(); 
      NodeList localNodeList2 = localElement.getElementsByTagName(TAG_LINK); 
      localElement.getAttribute("href"); 
      localArrayList.add(new RSSItem(str2, ((Element)localNodeList2.item(0)).getAttribute("href").split("&")[0].replace("https://www.google.com/url?q=", ""), Html.fromHtml(getValue(localElement, TAG_DESRIPTION)).toString(), setTime(getValue(localElement, TAG_PUB_DATE)), getValue(localElement, TAG_GUID))); 
     } 
     } 
     catch (Exception localException) 
     { 
     localException.printStackTrace(); 
     } 
    return localArrayList; 
    } 

    public String getValue(Element paramElement, String paramString) 
    { 
    return getElementValue(paramElement.getElementsByTagName(paramString).item(0)); 
    } 

    public String getXmlFromUrl(String paramString) 
    { 
    try 
    { 
     String str = EntityUtils.toString(new DefaultHttpClient().execute(new HttpGet(paramString)).getEntity()); 
     return str; 
    } 
    catch (UnsupportedEncodingException localUnsupportedEncodingException) 
    { 
     localUnsupportedEncodingException.printStackTrace(); 
     return null; 
    } 
    catch (ClientProtocolException localClientProtocolException) 
    { 
     localClientProtocolException.printStackTrace(); 
     return null; 
    } 
    catch (IOException localIOException) 
    { 
     localIOException.printStackTrace(); 
    } 
    return null; 
    } 
}

에서

import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.List; 



import android.app.ListActivity; 
import android.app.ProgressDialog; 
import android.content.Intent; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.View; 
import android.widget.AdapterView; 
import android.widget.AdapterView.OnItemClickListener; 
import android.widget.ImageButton; 
import android.widget.ListAdapter; 
import android.widget.ListView; 
import android.widget.SimpleAdapter; 
import android.widget.TextView; 

public class ListRSSItemsActivity extends ListActivity { 

    // Progress Dialog 
    private ProgressDialog pDialog; 

    // Array list for list view 
    ArrayList<HashMap<String, String>> rssItemList = new ArrayList<HashMap<String,String>>(); 

    RSSParser rssParser = new RSSParser(); 

    // button add new website 
    ImageButton btnAddSite; 

    List<RSSItem> rssItems = new ArrayList<RSSItem>(); 

    RSSFeed rssFeed; 

    private static String TAG_TITLE = "title"; 
    private static String TAG_LINK = "link"; 
    private static String TAG_DESRIPTION = "description"; 
    private static String TAG_PUB_DATE = "pubDate"; 
    private static String TAG_GUID = "guid"; // not used 
    private String urlString = "http://www.google.com/alerts/feeds/01662123773360489091/16526224428036307178"; 

    @Override 
    public void onCreate(Bundle paramBundle) 
     { 
     super.onCreate(paramBundle); 
     setContentView(R.layout.rss_item_list); 
     String str = urlString; 
     new loadRSSFeed().execute(str); 
     getListView().setOnItemClickListener(new AdapterView.OnItemClickListener() 
     { 
      public void onItemClick(AdapterView<?> paramAdapterView, View paramView, int paramInt, long paramLong) 
      { 
      Intent localIntent = new Intent(ListRSSItemsActivity.this.getApplicationContext(), DisPlayWebPageActivity.class); 
      localIntent.putExtra("page_url", ((TextView)paramView.findViewById(R.id.page_url)).getText().toString()); 
      ListRSSItemsActivity.this.startActivity(localIntent); 
      } 
     }); 
     } 

     class loadRSSFeed extends AsyncTask<String, String, String> 
     { 
     loadRSSFeed() 
     { 
     } 

     protected String doInBackground(String[] paramArrayOfString) 
     { 
      String str1 = paramArrayOfString[0]; 
      ListRSSItemsActivity.this.rssFeed = ListRSSItemsActivity.this.rssParser.getRSSFeed(str1); 
      Log.d("rssFeed", "rssFeed: " + ListRSSItemsActivity.this.rssFeed); 
      Log.d("rssFeed", "url: " + str1); 
      if (ListRSSItemsActivity.this.rssFeed != null) 
      { 
      Log.e("RSS URL", ListRSSItemsActivity.this.rssFeed.getTitle() + ListRSSItemsActivity.this.rssFeed.getLink() + ListRSSItemsActivity.this.rssFeed.getDescription() + ListRSSItemsActivity.this.rssFeed.getLanguage()); 
      WebSite localWebSite = new WebSite(ListRSSItemsActivity.this.rssFeed.getTitle(), ListRSSItemsActivity.this.rssFeed.getLink(), ListRSSItemsActivity.this.rssFeed.getRSSLink(), ListRSSItemsActivity.this.rssFeed.getDescription()); 
      HashMap localHashMap = new HashMap(); 
      localHashMap.put(ListRSSItemsActivity.TAG_TITLE, localWebSite.getTitle()); 
      localHashMap.put(ListRSSItemsActivity.TAG_LINK, localWebSite.getLink()); 
      String str2 = localWebSite.getDescription(); 
      if (str2.length() > 100) 
       str2 = str2.substring(0, 97) + ".."; 
      localHashMap.put(ListRSSItemsActivity.TAG_DESRIPTION, str2); 
      ListRSSItemsActivity.this.rssItemList.add(localHashMap); 
      } 
      ListRSSItemsActivity.this.runOnUiThread(new Runnable() 
      { 
      public void run() 
      { 
       ListRSSItemsActivity localListRSSItemsActivity = ListRSSItemsActivity.this; 
       ArrayList localArrayList = ListRSSItemsActivity.this.rssItemList; 
       String[] arrayOfString = new String[4]; 
       arrayOfString[0] = ListRSSItemsActivity.TAG_LINK; 
       arrayOfString[1] = ListRSSItemsActivity.TAG_TITLE; 
       arrayOfString[2] = ListRSSItemsActivity.TAG_PUB_DATE; 
       arrayOfString[3] = ListRSSItemsActivity. TAG_DESRIPTION; 
       SimpleAdapter localSimpleAdapter = new SimpleAdapter(localListRSSItemsActivity, localArrayList, R.layout.rss_item_list_row, arrayOfString, new int[] { R.id.page_url, R.id.title , R.id.pub_date, R.id.link }); 
       ListRSSItemsActivity.this.setListAdapter(localSimpleAdapter); 
      } 
      }); 
      return null; 
     } 

     protected void onPostExecute(String paramString) 
     { 
      ListRSSItemsActivity.this.pDialog.dismiss(); 
     } 

     protected void onPreExecute() 
     { 
      super.onPreExecute(); 
      ListRSSItemsActivity.this.pDialog = new ProgressDialog(ListRSSItemsActivity.this); 
      ListRSSItemsActivity.this.pDialog.setMessage("Fetching RSS Information ..."); 
      ListRSSItemsActivity.this.pDialog.setIndeterminate(false); 
      ListRSSItemsActivity.this.pDialog.setCancelable(false); 
      ListRSSItemsActivity.this.pDialog.show(); 
     } 
     } 

}

: ListRSSItemsActivity.java에서

: 당신은 같은 아래에있는 내 스크립트에서 문제가 있는지 확인하실 수 있습니다 rss_item_list_row.xml에서

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:orientation="vertical" 
    android:padding="8dip" > 

    <TextView android:id="@+id/page_url" 
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content" 
     android:visibility="gone"/> 

    <!-- Article title --> 
    <TextView 
     android:id="@+id/title" 
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content" 
     android:paddingBottom="1dip" 
     android:textSize="18dip" 
     android:textStyle="bold" 
     android:textColor="#303030" /> 

    <!-- published date --> 
    <TextView 
     android:id="@+id/pub_date" 
     android:layout_below="@id/title" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:paddingBottom="3dip" 
     android:textSize="14dip" 
     android:textColor="#b70400"/> 

    <!-- article description --> 
    <TextView android:id="@+id/link" 
     android:layout_height="wrap_content" 
     android:layout_width="wrap_content" 
     android:paddingBottom="6dip" 
     android:textSize="15dip" 
     android:textColor="#8d8d8d" 
     android:layout_below="@id/pub_date"/> 
</RelativeLayout>

내 오류 로그 캣 :

10-12 21:29:26.353: W/System.err(1697): java.lang.NullPointerException 
10-12 21:29:26.353: W/System.err(1697):  at com.a.b.RSSParser.getValue(RSSParser.java:157) 
10-12 21:29:26.353: W/System.err(1697):  at com.a.b.RSSParser.getRSSFeed(RSSParser.java:116) 
10-12 21:29:26.353: W/System.err(1697):  at com.a.b.ListRSSItemsActivity$loadRSSFeed.doInBackground(ListRSSItemsActivity.java:75) 
10-12 21:29:26.363: W/System.err(1697):  at com.a.b.ListRSSItemsActivity$loadRSSFeed.doInBackground(ListRSSItemsActivity.java:1) 
10-12 21:29:26.363: W/System.err(1697):  at android.os.AsyncTask$2.call(AsyncTask.java:288) 
10-12 21:29:26.363: W/System.err(1697):  at java.util.concurrent.FutureTask.run(FutureTask.java:237) 
10-12 21:29:26.363: W/System.err(1697):  at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 
10-12 21:29:26.363: W/System.err(1697):  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
10-12 21:29:26.363: W/System.err(1697):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
10-12 21:29:26.363: W/System.err(1697):  at java.lang.Thread.run(Thread.java:841) 
10-13 09:00:01.940: D/rssFeed(1816): rssFeed: null 
10-13 09:00:01.940: D/rssFeed(1816): url: http://www.google.com/alerts/feeds/01662123773360489091/16526224428036307178

나는 그것을 해결할 수 있습니까? 이 방법에서는

출처

2014-10-13 user3077416

+0

이 시도하면이 전체 스택 트레이스가 ? 'by by by'로 시작하는 행 확인 – Aniruddha

+0

@Aniruddha 위 XML 파일로 이미 업데이트했습니다 – user3077416

답변

0

는

public String getValue(Element paramElement, String paramString) { 
    return getElementValue(paramElement.getElementsByTagName(paramString).item(0)); 
}

어느 parentElement 또는 paramElement.getElementsByTagName(paramString) 널이다. 디버거를 실행하여 파악하십시오.

편집

대상의 XML 문서에

private String urlString = "http://www.google.com/alerts/feeds/01662123773360489091/16526224428036307178";

를 가져 오는, 당신은 채널 노드

private static String TAG_CHANNEL = "channel"; 
// [...] 
Element localElement = (Element)getDomElement(str1).getElementsByTagName(TAG_CHANNEL).item(0);

그러나 문서에서 이러한 태그를 찾고 있습니다. 그래서 localElement은 null입니다 (항목 (0)은 null을 반환합니다). 그래서

String str2 = getValue(localElement, TAG_TITLE);

EDIT2

(이 글의 시작 부분에 설명 된대로) getValue이 호출에서 NullPointerException이 트리거 getRSSFeed

Element localElement = getDomElement(str1).getDocumentElement(); 
String str2 = getValue(localElement, TAG_TITLE);

출처

2014-10-13 07:35:57 ToYonos

+0

위의 XML 파일을 확인하고 완료된 logcat – user3077416

+0

예, 여전히 맞습니다.) getRSSFeed가 null을 반환하면 rssFeed가 null입니다. . – ToYonos

+0

그래서이 솔루션을 urlString에서 paramString이 될 때까지 변경해야합니까? – user3077416

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