急android 程序里如何给地图里加marker

急~android 程序里怎么给地图里加marker
如题，怎么才能给搜索到得点加上标记呢，网页里的会，不过在android里似乎不一样呢，谢谢啦

[解决办法]
给出源码：（你自己照着做了）
package com.android.MapView;
import java.util.*;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;

import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.widget.Toast;

import com.android.CommSocket.*;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.ItemizedOverlay;
import com.google.android.maps.MapView;
import com.google.android.maps.OverlayItem;

public class SitesOverlay extends ItemizedOverlay {
private List items = new ArrayList();
private Drawable marker = null;
private MapViewActivity ref;


public SitesOverlay(Drawable marker,MapViewActivity r) {
super(marker);
this.marker = marker;
this.ref=r;

}

public void addOverlay(Double lat,Double lng ,String name,String info)
{
GeoPoint point = new GeoPoint(lat.intValue(), lng.intValue());
items.add(new OverlayItem(point, name, info));
populate();
}

@Override
protected OverlayItem createItem(int i) {
return (OverlayItem) (items.get(i));
}

@Override
public void draw(Canvas canvas, MapView mapView, boolean shadow) {
super.draw(canvas, mapView, shadow);

boundCenterBottom(marker);
}




public int size() {
return (items.size());
}
}

调用方法：
SitesOverlay o = new SitesOverlay(marker, this);
o.addOverlay(site.getLat(), site.getLng(), site.getId(), site.getContent());
mapView = (MapView) findViewById(R.id.map);
mapView.invalidate();

坐着等分了~~