android中的简单XML解析器无法正常工作

Question

应用程序应解析XML并输出到和ListView，但它似乎无法正常工作

我的代码

public class MainActivity extends AppCompatActivity {

ListView spiska;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    spiska = (ListView) findViewById(R.id.spiska);
    try {
        MainActivity obj = new MainActivity ();
        String[] arra = obj.run ("http://feeds.reuters.com/reuters/sportsNews?format=xml");

        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1, arra);

        spiska.setAdapter(adapter);
    }
    catch (Exception e)
    {
        e.printStackTrace();
    }
}

public String[] run (String url) throws Exception
{

    String[] forlist = new String[100];
    try {
        DocumentBuilderFactory f =
                DocumentBuilderFactory.newInstance();
        DocumentBuilder b = f.newDocumentBuilder();
        Document doc = b.parse(url);

        // loop through each item
        NodeList items = doc.getElementsByTagName("item");
        for (int i = 0; i < items.getLength(); i++) {
            Node n = items.item(i);
            if (n.getNodeType() != Node.ELEMENT_NODE)
                continue;
            Element e = (Element) n;

            // get the "title elem" in this item (only one)
            NodeList titleList =
                    e.getElementsByTagName("title");
            Element titleElem = (Element) titleList.item(0);

            // get the "text node" in the title (only one)
            Node titleNode = titleElem.getChildNodes().item(0);
            forlist[i] = titleNode.getNodeValue();
        }
    }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    return forlist;

}
}

android studio outputs

处理：com.example.javarulit，PID：15400                       java.lang.NullPointerException：尝试调用虚方法＆＃39; java.lang.String java.lang.Object.toString（）＆＃39;在空对象引用上

此代码适用于java

public class Main {

public static void main(String[] args) {
    System.out.println("Hell o world");

    try
    {
        Main obj = new Main ();
        obj.run ("http://feeds.reuters.com/reuters/sportsNews?format=xml");
    }
    catch (Exception e)
    {
        e.printStackTrace ();
    }

}
public void run (String url) throws Exception
{
    String[] forlist = new String[100];
    try
    {
        DocumentBuilderFactory f =
                DocumentBuilderFactory.newInstance();
        DocumentBuilder b = f.newDocumentBuilder();
        Document doc = b.parse(url);

        doc.getDocumentElement().normalize();
        System.out.println ("Root element: " +
                doc.getDocumentElement().getNodeName());

        // loop through each item
        NodeList items = doc.getElementsByTagName("item");
        for (int i = 0; i < items.getLength(); i++)
        {
            Node n = items.item(i);
            if (n.getNodeType() != Node.ELEMENT_NODE)
                continue;
            Element e = (Element) n;

            // get the "title elem" in this item (only one)
            NodeList titleList =
                    e.getElementsByTagName("title");
            Element titleElem = (Element) titleList.item(0);

            // get the "text node" in the title (only one)
            Node titleNode = titleElem.getChildNodes().item(0);
            forlist[i] = "\"" + titleNode.getNodeValue().toString() + "\"";
        }

        System.out.println(Arrays.toString(forlist));
    }
    catch (Exception e)
    {
        e.printStackTrace();
    }
}

}