Question

我使用的是sax xmlparser，我无法通过toast打印结果。我得到一个空指针异常。我找到了一个使用textview数组的例子，但我想使用toast。来自android人员的原始代码工作正常，但如果我在我自己的项目中应用相同的代码，它每次都会失败。

Main.java＆gt;

import java.net.URL;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.CheckBox;
import android.widget.Toast;

public class Main extends Activity {

String strGK = null;
String strHWW = null;
String strHak5 = null;

    CheckBox GK;
    CheckBox HWW;
    CheckBox Hak5;

    SitesList sitesList = null;

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

    public void getUrl(View v) {
        try {
            /** Handling XML */
            SAXParserFactory spf = SAXParserFactory.newInstance();
            SAXParser sp = spf.newSAXParser();
            XMLReader xr = sp.getXMLReader();

            /** Send URL to parse XML Tags */
            URL sourceUrl = new URL("http://websitethatcontains/feed");

            /** Create handler to handle XML Tags ( extends DefaultHandler ) */
            MyXMLHandler myXMLHandler = new MyXMLHandler();
            xr.setContentHandler(myXMLHandler);
            xr.parse(new InputSource(sourceUrl.openStream()));

        } catch (Exception e) {
            System.out.println("XML Parsing Exception = " + e);
        }

        /** Get result from MyXMLHandler SitlesList Object */
        sitesList = MyXMLHandler.sitesList;

        /** Set the result text in textview and add it to layout */
        for (int i = 0; i < sitesList.getName().size(); i++) { /** <- the prob. seems to be here */
            Toast.makeText(getApplicationContext(), sitesList.getName().get(i), Toast.LENGTH_LONG).show();
        }
    }
}

Answer 1

试

public void getUrl(View v) {
    MyXMLHandler myXMLHandler;
    try {
        /** Handling XML */
        SAXParserFactory spf = SAXParserFactory.newInstance();
        SAXParser sp = spf.newSAXParser();
        XMLReader xr = sp.getXMLReader();

        /** Send URL to parse XML Tags */
        URL sourceUrl = new URL("http://websitethatcontains/feed");

        /** Create handler to handle XML Tags ( extends DefaultHandler ) */
        myXMLHandler = new MyXMLHandler();
        xr.setContentHandler(myXMLHandler);
        xr.parse(new InputSource(sourceUrl.openStream()));

    } catch (Exception e) {
        System.out.println("XML Parsing Exception = " + e);
    }

    if (MyXMLHandler != null){
        /** Get result from MyXMLHandler SitlesList Object */
        sitesList = MyXMLHandler.sitesList;

        /** Set the result text in textview and add it to layout */
        for (int i = 0; i < sitesList.getName().size(); i++) { /** <- the prob. seems to be here */
            Toast.makeText(getApplicationContext(), sitesList.getName().get(i), Toast.LENGTH_LONG).show();
        }
    }
}

Android xml nullpointer异常xml解析器

1 个答案: