Question

我的代码从网站获取RSS提要并在列表视图中显示。我已编写代码，但显示空白页面。

MainActivity.java

package com.example.rssreadertest;

import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends ActionBarActivity implements OnClickListener {

    Button bt;
    EditText txt;
    RSSfeed feed;

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

        bt = (Button) findViewById(R.id.button1);
        txt = (EditText) findViewById(R.id.editText1);
        bt.setOnClickListener(this);
        Log.d("check", "onCreate was called");

    }

        public void onClick(View v)
        {
            int id=v.getId();

            switch(id)
            {

            case R.id.button1:

                Log.d("check", "Button was clicked");
                 String feedUrl = "http://www.websiteurl.com/feed/";
                 new AsyncLoadXMLFeed(feedUrl).execute();
                 Log.d("check", "url" +feedUrl +" was sent");
        }

    }

        private class AsyncLoadXMLFeed extends AsyncTask<Void, Void, Void>
        {

            String feedUrl;

            public AsyncLoadXMLFeed(String feedUrl) {
                this.feedUrl = feedUrl;
            }


            @Override
            protected Void doInBackground(Void... arg0) {

                DOMParser parser = new DOMParser();
                feed = parser.read(feedUrl);

                Log.d("check", "parsing begins");

                return null;            

            }


            @Override
            protected void onPostExecute(Void result) {
                // TODO Auto-generated method stub
                super.onPostExecute(result);

                Bundle bundle = new Bundle();
                bundle.putSerializable("feed", feed);
                Intent intent = new Intent(MainActivity.this, ListActivity.class);
                intent.putExtras(bundle);
                startActivity(intent);
                finish();

                Log.d("check", "here s the feed " +feed);


            }

        }

}

ListActivity.java

package com.example.rssreadertest;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;

public class ListActivity extends Activity {

    RSSfeed feed;
    CustomAdapter ca;
    ListView lv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.list_feed);

        Log.d("check", "entered");


        feed = (RSSfeed) getIntent().getExtras().get("feed");
        lv = (ListView) findViewById(R.id.listView1);

        ca = new CustomAdapter(this);
        lv.setAdapter(ca);

    }



    class CustomAdapter extends BaseAdapter {

        private LayoutInflater layoutInflater;

        public CustomAdapter(ListActivity listActivity) {
            // TODO Auto-generated constructor stub

            layoutInflater = (LayoutInflater) listActivity
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        }

        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            return feed.getItemcount();
        }

        @Override
        public Object getItem(int arg0) {
            // TODO Auto-generated method stub
            return arg0;
        }

        @Override
        public long getItemId(int arg0) {
            // TODO Auto-generated method stub
            return arg0;
        }

        @Override
        public View getView(int arg0, View arg1, ViewGroup arg2) {
            // TODO Auto-generated method stub



            View listItem = arg1;
            int pos = arg0;

            if (listItem == null) {
                listItem = layoutInflater.inflate(R.layout.list_item, null);
            }

            // Initialize the views in the layout
            TextView tvTitle = (TextView) listItem.findViewById(R.id.textView1);
            TextView tcDesc = (TextView) listItem.findViewById(R.id.textView2);

            Log.d("check", feed.getItem(pos).getTitle());
            Log.d("check", feed.getItem(pos).getDesc());


            tvTitle.setText(feed.getItem(pos).getTitle());
            tcDesc.setText(feed.getItem(pos).getDesc());
            return listItem;
        }

    }


}

DOMParser.java

package com.example.rssreadertest;

import java.net.MalformedURLException;
import java.net.URL;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;

import android.util.Log;

public class DOMParser {

    RSSfeed feed = new RSSfeed();
    RSSItem item = new RSSItem();
    public RSSfeed read(String link)
    {

        URL url = null;
        try {
            url = new URL(link);
        } catch (MalformedURLException e1) {
            e1.printStackTrace();
        }

        try {
            // Create required instances
            DocumentBuilderFactory dbf;
            dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder db = dbf.newDocumentBuilder();

            // Parse the xml
            Document doc = db.parse(new InputSource(url.openStream()));
            doc.getDocumentElement().normalize();

            // Get all <item> tags.
        NodeList nl = doc.getElementsByTagName("item");
            int length = nl.getLength();

                        for (int i = 0; i < length; i++) {
                            Node currentNode = nl.item(i);
                            NodeList nchild = currentNode.getChildNodes();
                            int clength = nchild.getLength();

                            // Get the required elements from each Item
                            for (int j = 0; j < clength; j = j++) {

                                Node thisNode = nchild.item(j);
                                String theString = null;
                                String nodeName = thisNode.getNodeName();

                                theString = nchild.item(j).getFirstChild().getNodeValue();

                                if (theString != null) {
                                    if ("title".equals(nodeName)) {
                                        // Node name is equals to 'title' so set the Node
                                        // value to the Title in the RSSItem.
                                        item.setTitle(theString);
                                        Log.d("check", "Title is " +theString);


                                    }

                                    else if ("description".equals(nodeName)) {
                                        item.setDesc(theString);
                                        Log.d("check", "desc is " +theString);

                                    }
                                }
                            }

                            // add item to the list
                            feed.addItem(item);
                        }

                    } 

        catch (Exception e) 
        {

        }



        return feed;

    }
}

RSSfeed.java

package com.example.rssreadertest;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

public class RSSfeed implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private List<RSSItem> itemlist = new ArrayList<RSSItem>();
    private int itemcount=0;
    public List<RSSItem> getItemlist() {
        return itemlist;
    }

    public void addItem(RSSItem item)
    {
        itemlist.add(item);
        itemcount++;
    }

    public int getItemcount() {
        return itemcount;
    }

    public RSSItem getItem(int arg0) {
        // TODO Auto-generated method stub
        return itemlist.get(arg0);
    }

}

RSSitem.java

public class RSSItem {

    private String title,desc;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getDesc() {
        return desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

}

布局文件：

activity_main.xml中

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.rssreadertest.MainActivity" >

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="158dp"
        android:text="Start to parse" />

</RelativeLayout>

list_feed.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="23dp"
        android:layout_marginTop="31dp"
        android:text="Large Text"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="35dp" >
    </ListView>

</RelativeLayout>

list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:text="Large Text"
        android:textColor="#FC0707"
        android:textStyle="bold"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/textView1"
        android:text="Small Text"
        android:textAppearance="?android:attr/textAppearanceSmall" />

</RelativeLayout>

我无法找到解决方案，因为它没有显示任何错误。任何帮助都会有用。

输出：

enter image description here

ListView是空白的，没有任何数据

0 个答案: