解析XML数据形成的Internet2

Question

你好，大家好我开发一个简单的应用程序，通过使用SAX读取来自互联网一个XML文件，但我得到的logcat此错误的任何帮助，可帮助

<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
package="com.reaf.xml" 
android:versionCode="1" 
android:versionName="1.0" > 
<uses-sdk 
android:minSdkVersion="8" 
android:targetSdkVersion="15" /> 
<uses-permission android:name="android.permission.INTERNET" /> 
<application 
android:icon="@drawable/ic_launcher" 
android:label="@string/app_name" 
android:theme="@style/AppTheme" > 
<activity 
    android:name="com.read.xml.DataHandler" 
    android:label="@string/title_activity_main" > 
    <intent-filter> 
     <action android:name="android.intent.action.MAIN" /> 

     <category android:name="android.intent.category.LAUNCHER" /> 
    </intent-filter> 
</activity> 
<activity android:name=".MainActivity" > 
</activity> 
</application> 
</manifest> 

logcat的

 10-06 08:29:52.204: D/AndroidRuntime(614): Shutting down VM 
     10-06 08:29:52.204: W/dalvikvm(614): threadid=1: thread exiting with uncaught exception (group=0x40015560) 
     10-06 08:29:52.254: E/AndroidRuntime(614): FATAL EXCEPTION: main 
     10-06 08:29:52.254: E/AndroidRuntime(614): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.read.xml/com.read.xml.DataHandler}: java.lang.ClassCastException: com.read.xml.DataHandler 
    10-06 08:29:52.254: E/AndroidRuntime(614):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1569) 
     10-06 08:29:52.254: E/AndroidRuntime(614): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 
     10-06 08:29:52.254: E/AndroidRuntime(614): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 
    10-06 08:29:52.254: E/AndroidRuntime(614):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 
     10-06 08:29:52.254: E/AndroidRuntime(614): at android.os.Handler.dispatchMessage(Handler.java:99) 
     10-06 08:29:52.254: E/AndroidRuntime(614): at android.os.Looper.loop(Looper.java:123) 
    10-06 08:29:52.254: E/AndroidRuntime(614):  at android.app.ActivityThread.main(ActivityThread.java:3683) 
    10-06 08:29:52.254: E/AndroidRuntime(614): at java.lang.reflect.Method.invokeNative(Native Method) 
    10-06 08:29:52.254: E/AndroidRuntime(614): at java.lang.reflect.Method.invoke(Method.java:507) 
    10-06 08:29:52.254: E/AndroidRuntime(614): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
    10-06 08:29:52.254: E/AndroidRuntime(614): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 

8月10日至6日：29：52.254：E/AndroidRuntime（614）：在dalvik.system.NativeStart.main（本机方法） 8月10日至6日：29：52.254：E/AndroidRuntime（614）：引起：java.lang.ClassCastException：com.read.xml.DataHandler 10-06 08：29：52.254：E/AndroidRuntime（614）：在android.app.Instrumentation.newActivity（Instrumentation.java:1021） 10-06 08：29：52.254：E/AndroidRuntime（614）：at android.app.ActivityThread.performLaunchActivity（ActivityThread.java ：1561） 10-06 08：29：52.254：E/AndroidRuntime（614）：... 11更多 10-06 08：29：54.514：I /进程（614）：发送信号。 PID：614 SIG：9

，这是的DataHandler类

   package com.read.xml; 

    import java.io.BufferedReader; 
    import java.io.IOException; 
    import java.io.InputStreamReader; 
    import java.net.URL; 
    import java.net.URLConnection; 
    import java.util.ArrayList; 

    import javax.xml.parsers.SAXParser; 
    import javax.xml.parsers.SAXParserFactory; 

    import org.xml.sax.Attributes; 
    import org.xml.sax.InputSource; 
    import org.xml.sax.SAXException; 
    import org.xml.sax.XMLReader; 
    import org.xml.sax.helpers.DefaultHandler; 

    import android.content.Context; 
    import android.graphics.Color; 
import android.util.Log; 
import android.widget.TextView; 

    public class DataHandler extends DefaultHandler { 

//list for imported product data 
private ArrayList<TextView> theViews; 
//string to track each entry 
private String currBrand = ""; 
//flag to keep track of XML processing 
private boolean isProduct = false; 
//context for user interface 
private Context theContext; 
//constructor 
public DataHandler(Context cont) { 
    super(); 
    theViews = new ArrayList<TextView>(); 
    theContext = cont; 
} 
//start of the XML document 
public void startDocument() 
{ Log.i("DataHandler", "Start of XML document"); } 

//end of the XML document 
public void endDocument() 
{ Log.i("DataHandler", "End of XML document"); } 

//opening element tag 
public void startElement (String uri, String name, String qName, Attributes atts) 
{ 
    //find out if the element is a brand 
    if(qName.equals("brand")) 
    { 
     //set product tag to false 
     isProduct = false; 
     //create View item for brand display 
     TextView brandView = new TextView(theContext); 
     brandView.setTextColor(Color.rgb(73, 136, 83)); 
     //add the attribute value to the displayed text 
     String viewText = "Items from " + atts.getValue("name") + ":"; 
     brandView.setText(viewText); 
     //add the new view to the list 
     theViews.add(brandView); 
    } 
    //the element is a product 
    else if(qName.equals("product")) 
     isProduct = true; 
} 

//closing element tag 
public void endElement (String uri, String name, String qName) 
{ 
    if(qName.equals("brand")) 
    { 
     //create a View item for the products 
     TextView productView = new TextView(theContext); 
     productView.setTextColor(Color.rgb(192, 199, 95)); 
     //display the compiled items 
     productView.setText(currBrand); 
     //add to the list 
     theViews.add(productView); 
     //reset the variable for future items 
     currBrand = ""; 
    } 
} 

//element content 
public void characters (char ch[], int start, int length) 
{ 
    //string to store the character content 
    String currText = ""; 
    //loop through the character array 
    for (int i=start; i<start+length; i++) 
    { 
     switch (ch[i]) { 
     case '\\': 
      break; 
     case '"': 
      break; 
     case '\n': 
      break; 
     case '\r': 
      break; 
     case '\t': 
      break; 
     default: 
      currText += ch[i]; 
      break; 
     } 
    } 
    //prepare for the next item 
    if(isProduct && currText.length()>0) 
     currBrand += currText+"\n"; 
} 

public ArrayList<TextView> getData() 
{ 
    //take care of SAX, input and parsing errors 
    try 
    { 
      //set the parsing driver 
     System.setProperty("org.xml.sax.driver","org.xmlpull.v1.sax2.Driver"); 
      //create a parser 
     SAXParserFactory parseFactory = SAXParserFactory.newInstance(); 
     SAXParser xmlParser = parseFactory.newSAXParser(); 
      //get an XML reader 
     XMLReader xmlIn = xmlParser.getXMLReader(); 
      //instruct the app to use this object as the handler 
     xmlIn.setContentHandler(this); 
      //provide the name and location of the XML file 
     URL xmlURL = new URL("www.data-online.bugs3.com/public_html/test.xml"); 
      //open the connection and get an input stream 
     URLConnection xmlConn = xmlURL.openConnection(); 
     InputStreamReader xmlStream = new  
      InputStreamReader(xmlConn.getInputStream()); 
      //build a buffered reader 
     BufferedReader xmlBuff = new BufferedReader(xmlStream); 
      //parse the data 
     xmlIn.parse(new InputSource(xmlBuff)); 
    } 
    catch(SAXException se) { Log.e("AndroidTestsActivity", 
      "SAX Error " + se.getMessage()); } 
    catch(IOException ie) { Log.e("AndroidTestsActivity", 
      "Input Error " + ie.getMessage()); } 
    catch(Exception oe) { Log.e("AndroidTestsActivity", 
      "Unspecified Error " + oe.getMessage()); } 
     //return the parsed product list 
    return theViews; 
} 


} 

我不知道什么是错误

请帮助

Answer 1

你在哪里打电话DataHandler.getData？如果这是在一个活动构造函数或创建调用中，这将导致NetworkOnMainThreadException。

如果是这样，请考虑的AsyncTask的情况：http://developer.android.com/reference/android/os/AsyncTask.html

您需要调用的getData在doInBackground。

Answer 2

您没有空的构造函数集集。你应该有一个空的构造函数来使用newInstance方法，就像我在前面的问题中提到的那样。类似于

public DataHandler() { 
}