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POjava.lang.RuntimeException: Unable to start activity ComponentInfo java.lang.NullPointerException
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  1. POjava.lang.RuntimeException: Unable to start activity ComponentInfo java.lang.NullPointerException
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    copied!<p>I created an app to parse a XML file using SAXParser and the code is below.</p> <p>Below is the code of my main activity.</p> <pre><code>public class XMLAppActivity extends Activity{ ArrayList&lt;Question&gt; questionList = new ArrayList&lt;Question&gt;(); TextView tvXmlReader; InputSource xmlSource; InputStream xmlIs; String xmlFile; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); tvXmlReader=(TextView)findViewById(R.id.my_xml); try { xmlIs= getAssets().open("surveyquestions.xml"); xmlFile = convertStreamToString(xmlIs); } catch (IOException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } xmlSource= new InputSource(new StringReader(xmlFile)); tvXmlReader.setText(parseXML().toString()); } private String parseXML() { try { /** Handling XML */ SAXParserFactory spf = SAXParserFactory.newInstance(); SAXParser sp = spf.newSAXParser(); XMLReader xr = sp.getXMLReader(); QuestionXMLHandler myXMLHandler = new QuestionXMLHandler(); xr.setContentHandler(myXMLHandler); xr.parse(xmlSource); questionList= myXMLHandler.getQuestionList(); return "Success"; } catch (Exception e) { return "Failure due to " + e.toString(); } } public String convertStreamToString(InputStream is) throws IOException { Writer writer = new StringWriter(); char[] buffer = new char[2048]; try { Reader reader = new BufferedReader(new InputStreamReader(is,"UTF-8")); int n; while ((n = reader.read(buffer)) != -1) { writer.write(buffer, 0, n); } } finally { is.close(); } String text = writer.toString(); return text; } } </code></pre> <p>This is the code for my XMLhandler.</p> <pre><code>public class QuestionXMLHandler extends DefaultHandler { private ArrayList&lt;Question&gt; questionL= new ArrayList&lt;Question&gt;(); Question cQuestion; Boolean cElement = false; String cValue = ""; public ArrayList&lt;Question&gt; getQuestionList() { return questionL; } @Override public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { cElement = true; cValue = ""; // if current element is Question , create new question // clear tmpValue on start of element if (qName.equalsIgnoreCase("Question")) { cQuestion = new Question(); cQuestion.setQuestionId(attributes.getValue("id")); cQuestion.setQuestionName(attributes.getValue("name")); cQuestion.setQuestionType(attributes.getValue("type")); cQuestion.setQuestionIsRequired(Boolean.parseBoolean(attributes.getValue("isRequired"))); } } @Override public void endElement(String uri, String localName, String qName) throws SAXException { if (qName.equalsIgnoreCase("Question")) { questionL.add(cQuestion); } if (qName.equalsIgnoreCase("QuestionText")) { cQuestion.setQuestionText(cValue); } if(qName.equalsIgnoreCase("Answer")){ cQuestion.getAnswers().add(cValue); } } @Override public void characters(char[] ch, int start, int length) throws SAXException { // TODO Auto-generated method stub cValue = new String(ch,start,length); } } </code></pre> <p>And This is my Question class.</p> <pre><code>public class Question { private String qId; private String qName; private String qType; private String qText; private Boolean isRequired; private String qSurveyId; private List&lt;String&gt; answers; public Question() { qId=""; qName=""; qType=""; qText=""; isRequired=false; qSurveyId=""; } //getters and setter methods } </code></pre> <p>But I m getting an error of:</p> <pre><code>06-27 14:44:36.148: W/System.err(591): java.lang.NullPointerException 06-27 14:44:36.187: W/System.err(591): at com.optimus.mobile.xml.QuestionXMLHandler.endElement(QuestionXMLHandler.java:52) 06-27 14:44:36.187: W/System.err(591): at org.apache.harmony.xml.ExpatParser.endElement(ExpatParser.java:160) 06-27 14:44:36.187: W/System.err(591): at org.apache.harmony.xml.ExpatParser.append(Native Method) 06-27 14:44:36.187: W/System.err(591): at org.apache.harmony.xml.ExpatParser.parseFragment(ExpatParser.java:505) 06-27 14:44:36.197: W/System.err(591): at org.apache.harmony.xml.ExpatParser.parseDocument(ExpatParser.java:492) 06-27 14:44:36.197: W/System.err(591): at org.apache.harmony.xml.ExpatReader.parse(ExpatReader.java:308) 06-27 14:44:36.197: W/System.err(591): at org.apache.harmony.xml.ExpatReader.parse(ExpatReader.java:264) 06-27 14:44:36.197: W/System.err(591): at com.optimus.mobile.xml.XMLAppActivity.parseXML(XMLAppActivity.java:68) 06-27 14:44:36.197: W/System.err(591): at com.optimus.mobile.xml.XMLAppActivity.onCreate(XMLAppActivity.java:52) 06-27 14:44:36.197: W/System.err(591): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 06-27 14:44:36.197: W/System.err(591): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627) 06-27 14:44:36.197: W/System.err(591): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 06-27 14:44:36.197: W/System.err(591): at android.app.ActivityThread.access$2300(ActivityThread.java:125) 06-27 14:44:36.197: W/System.err(591): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 06-27 14:44:36.197: W/System.err(591): at android.os.Handler.dispatchMessage(Handler.java:99) 06-27 14:44:36.207: W/System.err(591): at android.os.Looper.loop(Looper.java:123) 06-27 14:44:36.207: W/System.err(591): at android.app.ActivityThread.main(ActivityThread.java:4627) 06-27 14:44:36.207: W/System.err(591): at java.lang.reflect.Method.invokeNative(Native Method) 06-27 14:44:36.207: W/System.err(591): at java.lang.reflect.Method.invoke(Method.java:521) 06-27 14:44:36.207: W/System.err(591): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 06-27 14:44:36.207: W/System.err(591): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 06-27 14:44:36.207: W/System.err(591): at dalvik.system.NativeStart.main(Native Method) </code></pre>
 

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