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Android开发使用Dom从网络端解析xml文件

2013-05-06 23:17 453 查看
本程序实现了从网络端解析xml文件,展示在列表,并实现点击进入相关页面。





首先我们创建一个类,用来实现http请求和xml文件节点的获取
public class XMLParser {

// constructor
public XMLParser() {

}

/**
* Getting XML from URL making HTTP request
* @param url string
* */
public String getXmlFromUrl(String url) {
String xml = null;
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
xml = EntityUtils.toString(httpEntity,"utf-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
// return XML
return xml;
}

/**
* Getting XML DOM element
* @param XML string
* */
public Document getDomElement(String xml){
Document doc = null;
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
try {

DocumentBuilder db = dbf.newDocumentBuilder();

InputSource is = new InputSource();
is.setCharacterStream(new StringReader(xml));
doc = db.parse(is);

} 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 doc;
}

/** Getting node value
* @param elem element
*/
public final String getElementValue( Node elem ) {
Node child;
if( elem != null){
if (elem.hasChildNodes()){
for( child = elem.getFirstChild(); child != null; child = child.getNextSibling() ){
if( child.getNodeType() == Node.TEXT_NODE  ){
return child.getNodeValue();
}
}
}
}
return "";
}
/**
* Getting node value
* @param Element node
* @param key string
* */
public String getValue(Element item, String str) {
NodeList n = item.getElementsByTagName(str);
return this.getElementValue(n.item(0));
}
}


然后我们创建一个Activity继承与ListActivity,在这个Activity中定义一些节点。
public class AndroidXMLParsingActivity extends ListActivity {

// All static variables
static final String URL = "http://10.0.2.2/biyeshejidata/menu.xml";
// XML node keys
static final String KEY_ITEM = "item"; // parent node
static final String KEY_ID = "id";
static final String KEY_NAME = "name";
static final String KEY_COST = "cost";
static final String KEY_DESC = "description";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

ArrayList<HashMap> menuItems = new ArrayList<HashMap>();

XMLParser parser = new XMLParser();
String xml = parser.getXmlFromUrl(URL); // getting XML
Document doc = parser.getDomElement(xml); // getting DOM element

NodeList nl = doc.getElementsByTagName(KEY_ITEM);
// looping through all item nodes
for (int i = 0; i < nl.getLength(); i++) {
// creating new HashMap
HashMap map = new HashMap();
Element e = (Element) nl.item(i);
// adding each child node to HashMap key => value
map.put(KEY_ID, parser.getValue(e, KEY_ID));
map.put(KEY_NAME, parser.getValue(e, KEY_NAME));
map.put(KEY_COST, "Rs." + parser.getValue(e, KEY_COST));
map.put(KEY_DESC, parser.getValue(e, KEY_DESC));

// adding HashList to ArrayList
menuItems.add(map);
}

// Adding menuItems to ListView
ListAdapter adapter = new SimpleAdapter(this, menuItems,
R.layout.list_item,
new String[] { KEY_NAME, KEY_DESC, KEY_COST }, new int[] {
R.id.name, R.id.desciption, R.id.cost });

setListAdapter(adapter);

// selecting single ListView item
ListView lv = getListView();

lv.setOnItemClickListener(new OnItemClickListener() {

@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String name = ((TextView) view.findViewById(R.id.name)).getText().toString();
String cost = ((TextView) view.findViewById(R.id.cost)).getText().toString();
String description = ((TextView) view.findViewById(R.id.desciption)).getText().toString();

// Starting new intent
Intent in = new Intent(getApplicationContext(), SingleMenuItemActivity.class);
in.putExtra(KEY_NAME, name);
in.putExtra(KEY_COST, cost);
in.putExtra(KEY_DESC, description);
startActivity(in);

}
});
}
}


最后实现点击进入一个新的页面的Activity
public class SingleMenuItemActivity  extends Activity {

// XML node keys
static final String KEY_NAME = "name";
static final String KEY_COST = "cost";
static final String KEY_DESC = "description";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.single_list_item);

// getting intent data
Intent in = getIntent();

// Get XML values from previous intent
String name = in.getStringExtra(KEY_NAME);
String cost = in.getStringExtra(KEY_COST);
String description = in.getStringExtra(KEY_DESC);

// Displaying all values on the screen
TextView lblName = (TextView) findViewById(R.id.name_label);
TextView lblCost = (TextView) findViewById(R.id.cost_label);
TextView lblDesc = (TextView) findViewById(R.id.description_label);

lblName.setText(name);
lblCost.setText(cost);
lblDesc.setText(description);
}
}
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