android - 从内部存储解析 Android XML

Question

我正在尝试使用 DOM 和 PullParser 读取和写入 XML 文件。我从这个链接http://www.phonesdevelopers.com/1707053/启发了这段代码的一部分。这是主要活动：

public class MainActivity extends Activity implements OnClickListener {
Button button;
ListView listView;
List<Classe> classes = null;
// XML node names
static final String NODE_CL = "tns:classe";
@Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    findViewsById();
    try {
        testClasse() ;
        testSave();
    } catch (Exception e) {
        e.printStackTrace();
    }
    
    
    button.setOnClickListener(this);
}

private void findViewsById() {
     button = (Button) findViewById(R.id.button);
        listView = (ListView) findViewById(R.id.employeeList);      
}

@Override
public void onClick(View v) {
XMLDOMParser parser = new XMLDOMParser();

File file = new File("data/data/com/theopentutorials/android/xy.xml");

    InputStream is;
try {
    is = new FileInputStream(file.getPath());
    Document doc = parser.getDocument(is);
    // Get elements by name employee
    NodeList nodeList = doc.getElementsByTagName(NODE_CL);
    classes = new ArrayList<Classe>();
    /*
     * for each <employee> element get text of name, department, type
     * and email and line1, city, state, zipcode of <address> element.
     */
    for (int i = 0; i < nodeList.getLength(); i++) {
        Element c = (Element) nodeList.item(i);
        Classe classe = new Classe();
        classe.setName(c.getAttribute("namecls"));
        classes.add(classe);
    }
    displayOutput();

} catch (IOException e1) {
    e1.printStackTrace();
}
}
private void displayOutput() {
    ArrayAdapter<Classe> adapter = new ArrayAdapter<Classe>(this,R.layout.list_item,classes);
    listView.setAdapter(adapter);
}        
public void testClasse() throws Exception  
{  
    ClasseService ps = new ClasseService();  
    InputStream xml = this.getClass().getClassLoader().getResourceAsStream("Classe.xml");  
    List<Classe> lst = ps.getPeople(xml);  
}  

public void testSave() throws Exception  
{  
    ClasseService ps = new ClasseService();  
    List<Classe> lst = new ArrayList<Classe>();  
    lst.add(new Classe("XY0001"));  
    lst.add(new Classe("0002"));  
    File xmlFile = new File(this.getBaseContext().getFilesDir(), "xy.xml"); // data/data/package name/files  
    OutputStream os = new FileOutputStream(xmlFile);  
    ps.saveDataToXML(os, lst);
}
}

这是 XML 解析器

public class XMLDOMParser {
//Returns the entire XML document 
  public static Document getDocument(InputStream inputStream) {
    Document document = null;
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    try {
        DocumentBuilder db = factory.newDocumentBuilder();
        InputSource inputSource = new InputSource(inputStream);
        document = db.parse(inputSource);
        document.getDocumentElement().normalize();
    } catch (ParserConfigurationException e) {
        Log.e("Error: ", e.getMessage());
        return null;
    } catch (SAXException e) {
        Log.e("Error: ", e.getMessage());
        return null;
    } catch (IOException e) {
        Log.e("Error: ", e.getMessage());
        return null;
    }
    return document;
}

/*
 * I take a XML element and the tag name, look for the tag and get
 * the text content i.e for <employee><name>Kumar</name></employee>
 * XML snippet if the Element points to employee node and tagName 
 * is name I will return Kumar. Calls the private method 
 * getTextNodeValue(node) which returns the text value, say in our 
 * example Kumar. */
public String getValue(Element item, String name) {
    NodeList nodes = item.getElementsByTagName(name);
    return this.getTextNodeValue(nodes.item(0));
}

private final String getTextNodeValue(Node node) {
    Node child;
    if (node != null) {
        if (node.hasChildNodes()) {
            child = node.getFirstChild();
            while(child != null) {
                if (child.getNodeType() == Node.TEXT_NODE) {
                    return child.getNodeValue();
                }
                child = child.getNextSibling();
            }
        }
    }
    return "";
}  
}

我们在其中进行写作的 ClasseService 类

public class ClasseService  
{  
/** 
 * XML 
 *  
 * @param xml XML 
 */  
public List<Classe> getPeople(InputStream xml) throws Exception  
{  
    List<Classe> lst = null; 
    com.theopentutorials.android.beans.Classe classe = null;

    // ANDROIDAPIpull  
    XmlPullParser pullParser = Xml.newPullParser();  

    // XML  
    pullParser.setInput(xml, "UTF-8");  

    //   
    int event = pullParser.getEventType();  

    //   
    while (event != XmlPullParser.END_DOCUMENT) //   
    {   String nodeName = pullParser.getName();  
    switch (event)  
    {  
        case XmlPullParser.START_DOCUMENT: //   
            lst = new ArrayList<Classe>();  
            break;  
        case XmlPullParser.START_TAG: //   
            if ("tns:classe".equals(nodeName))  
            {  
                String id = pullParser.getAttributeValue(0);  
                 classe = new Classe();  
                classe.setName(id);  
            }  
            
            break;    
    }  
    }
    return lst;  
}  

/** 
 * XML 
 *  
 * @param os 
 * @param Classe 
 * @throws Exception 
 */  
public void saveDataToXML(OutputStream os, List<Classe> lst) throws Exception  
{  
    XmlSerializer xs = Xml.newSerializer();  
    xs.setOutput(os, "UTF-8");  
    xs.startDocument("UTF-8", true);  
    xs.startTag(null, "tns:Classes");  
    for (Classe p : lst)  
    {  
        xs.startTag(null, "tns:classe");
        xs.attribute(null,"name",p.getName());  
        xs.endTag(null, "tns:classe");
        
    }  
    xs.endTag(null, "Classes");  
    xs.endDocument();  
    os.flush();  
    os.close();  
}  
}  

最后这是xml文件classe.xml

<?xml version="1.0" encoding="UTF-8"?>
<tns:Classes xmlns:tns="http://www.example.org/classe" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.example.org/classe classe.xsd ">
<tns:classe namecls="SmallArc"/>
<tns:classe namecls="SmallBar"/>
<tns:classe namecls="SmallTrunk"/>
<tns:classe namecls="SouthEastLine"/>
<tns:classe namecls="SouthEastLittleLine"/>
</tns:Classes>