怎么在 OverlayItem 中展示 图片和文字

如何在 OverlayItem 中展示 图片和文字
package com.mainaer.android.Map;

import java.util.ArrayList;

import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;
import android.graphics.drawable.Drawable;

import com.google.android.maps.ItemizedOverlay;
import com.google.android.maps.MapView;
import com.google.android.maps.Projection;

import com.google.android.maps.OverlayItem;

public class GeoItemizedOverlay extends ItemizedOverlay<OverlayItem> {

private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>();

public GeoItemizedOverlay(Drawable defaultMarker) {
super( boundCenterBottom(defaultMarker));

}

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

@Override
public int size() {
return mOverlays.size();
}

public void addOverlay(OverlayItem overlay) {
mOverlays.add(overlay);
populate();
}

public void draw(Canvas canvas, MapView mapView, boolean shadow) {
Projection projection = mapView.getProjection();
for (int index = size() - 1; index >= 0; index--) {
OverlayItem overLayItem = getItem(index);
/* 题目 */
String title = overLayItem.getTitle();
/* 简介 */
String snippet = overLayItem.getSnippet();
/* 象素点取得转换 */
Point point = projection.toPixels(overLayItem.getPoint(), null);

/* 目标城市圈出来 */
Paint paintCircle = new Paint();
paintCircle.setColor(Color.YELLOW);
canvas.drawCircle(point.x, point.y, 5, paintCircle);

/* 文字设置 */
Paint paintText = new Paint();
paintText.setColor(Color.RED);
paintText.setTextSize(25);

canvas.drawText(title+snippet, point.x, point.y, paintText);
}
super.draw(canvas, mapView, shadow);
}

}

在 onCreate 里面
调用：
public class WhereToBuy extends MapActivity {

MapView mMap;
TextView mCurrentCityName;
EditText mKey;
ImageButton mSwitchCity;
ImageButton mSearch;
Location mCurrentLocation;
GpsLocationListener mGpsLocation;
MapController mapController;

GeoItemizedOverlay itemizedOverlay;
Drawable drawable;
List<Overlay> mapOverlays;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
initCtrl();

mMap.setBuiltInZoomControls(true);
mMap.setClickable(true);
mMap.setEnabled(true);

GeoPoint point1 = new GeoPoint(19240000, -99120000);
GeoPoint point2 = new GeoPoint(35410000, 139460000);
// 设置初始地图的中心位置
  GeoPoint geoBeijing=new GeoPoint((int)(39.95*1000000), (int)(116.37*1000000));
   
  OverlayItem bjItem = new OverlayItem(geoBeijing, "JQQ", "Bei jing Welcome you !!");

OverlayItem overlayitem1 = new OverlayItem(point1, "DHZ", "what are you doing now ?");
overlayitem1.setMarker(drawable);
OverlayItem overlayitem2 = new OverlayItem(point2, "SRH", "where are you from ?");
overlayitem1.setMarker(drawable);

itemizedOverlay.addOverlay(overlayitem1);
itemizedOverlay.addOverlay(overlayitem2);
itemizedOverlay.addOverlay(bjItem);

mapOverlays.add(itemizedOverlay);
mapController.animateTo(geoBeijing);
mapController.setCenter(geoBeijing);
mapController.setZoom(9);

}

protected void initCtrl() {
mMap = (MapView) findViewById(R.id.mMap);
mCurrentCityName = (TextView) findViewById(R.id.mCurrentCity);
mKey = (EditText) findViewById(R.id.mKey);