1

我有一个正在解析的 Rss 提要。我需要它按发布日期从上到下进行排序和组织。这是我正在使用的代码。

XML 解析器

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);

    } 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));
    }
 }

解析活动

 public class AndroidXMLParsingActivity extends ListActivity {

// All static variables
static final String URL = "http://www.cpcofc.org/devoapp.xml";
// XML node keys
static final String KEY_ITEM = "item"; // parent node
static final String KEY_ID = "item";
static final String KEY_NAME = "title";
static final String KEY_COST = "description";
static final String KEY_DESC = "description";

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

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

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

    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 <item>
    for (int i = 0; i < nl.getLength(); i++) {
        // creating new HashMap
        HashMap<String, String> map = new HashMap<String, String>();
        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, 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_DESC, KEY_NAME, KEY_COST}, new int[] {
                    R.id.desciption, R.id.name, 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();

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

        }
    });
}
 }

这是现在的样子

在此处输入图像描述

我需要在顶部显示第 1 天的反面。有人对如何使这项工作有任何想法吗？

4

3 回答 3

3

你只需要颠倒List的顺序就可以实现你想要的，我们可以使用java集合框架提供的Collections类...这里是简单的代码

Collections.reverse(menuItems);

它会逆转你的收藏......我希望这会对你有所帮助

于 2013-01-11T05:03:18.320 回答
0

您不需要重写 ArrayAdapter 类为您实现的排序。您需要做的就是创建自己的 Comparator，它将按照您希望它们出现的方式对泛型类型对象进行排序。此外，如果您使用这种方法，您的代码应该可以正常工作。

adapter = new CustomAdapter(this, R.layout.list,R.id.title, data);

adapter.sort(new Comparator<RowData>() {
    public int compare(RowData arg0, RowData arg1) {
        return arg0.mProductName.compareTo(arg1.mProductName);
    }
});

setListAdapter(adapter);
adapter.notifyDataSetChanged();

更多参考..

http://www.vogella.com/articles/AndroidListView/article.html#listview_filtersort

https://github.com/bauerca/drag-sort-listview/tree/master/demo

于 2013-01-11T05:03:35.770 回答
0

之前的两个答案都会花费您一些性能，因为它们至少会循环遍历 ArrayList 一次。

您可以像这样简单地为您的循环使用反向迭代器：

 int len = nl.getLength();
 for (int i = len; i > 0; --i)

我还将数组的长度提取到一个局部变量中，因为它比每次调用 getLength 方法都要快。

于 2013-02-22T14:43:04.643 回答