Android : Want To Implement App On ListView Instead Of TextView

In my project whenever I extend activity it works fine but as soon as I extend ListActivity it throws exception and shows file not found. Why is that? We already know that ListActivity itself extends the Activity class. The application must run fine.

Here's the java file:

package com.android.feedGrabber;

import java.net.URL;
import java.net.URLConnection;
import java.util.Collection;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

import com.sun.cnpi.rss.elements.Item;
import com.sun.cnpi.rss.elements.Rss;
import com.sun.cnpi.rss.parser.RssParser;
import com.sun.cnpi.rss.parser.RssParserFactory;

If I change "extends Activity" to "extends ListActivity" it gives the exception. I need to bring this change because I want to implement it on ListView instead of TextView.

Error it throws:
debug mode gets active and it highlights under Suspended(exception RunTimeException): ActivityThread.performLaunchActivity(ActivityThread$ActivityRecord, Intent) line: 2663.