Eclipse调试的时候Source not found，什么情况解决办法

package com.app.MainActivity;import java.io.IOException;import org.xmlpull.v1.XmlPullParser;import org.xmlpull.v1.XmlPullParserException;import android.app.Activity;import android.content.res.XmlResourceParser;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.TextView;public class Chapter03_ResourceActivity extends Activity {    /** Called when the activity is first created. */    private Button myButton;    final private TextView myTextView = (TextView)findViewById(R.id.text_xml);    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        myButton = (Button)findViewById(R.id.btn_xml);        myButton.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {            StringBuilder sb = new StringBuilder();                   <==断点            XmlResourceParser xrp = getResources().getXml(R.xml.test);            int counter = 0;            try {                while(xrp.getEventType() != XmlPullParser.END_DOCUMENT) {                    if(xrp.getEventType() == XmlPullParser.START_TAG) {                        String name = xrp.getName();                        if(name.equals("customer")) {                            counter ++;                            sb.append(counter + " Customer" + "\n");                            sb.append(xrp.getAttributeValue(0) + "\n");                            sb.append(xrp.getAttributeValue(1) + "\n");                            sb.append(xrp.getAttributeValue(2) + "\n\n");                        }                         xrp.next();                    }                }             myTextView.setText(sb.toString());            } catch(IOException e) {                e.printStackTrace();            } catch(XmlPullParserException e) {                e.printStackTrace();            }             }        });    }}