Menampilkan overlay diatas map

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.map.marker"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="8" />

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" >
    </uses-permission>
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" >
    </uses-permission>

    <application
        android:icon="@drawable/marker"
        android:label="@string/app_name" >
        <activity
            android:name=".MapMarker"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <uses-library android:name="com.google.android.maps" />
    </application>

</manifest>

CustomOverlay.java

package com.map.marker;

import java.util.ArrayList;

import android.app.AlertDialog;
import android.content.Context;
import android.graphics.drawable.Drawable;

import com.google.android.maps.ItemizedOverlay;
import com.google.android.maps.OverlayItem;

public class CustomOverlay extends ItemizedOverlay<OverlayItem> {
	
	private ArrayList<OverlayItem> mapOverlays = new ArrayList<OverlayItem>();
	private Context context;

	public CustomOverlay(Drawable defaultMarker) {
		super(boundCenterBottom(defaultMarker));
		// TODO Auto-generated constructor stub
	}

	public CustomOverlay(Drawable defaultMarker, Context context) {
		this(defaultMarker);
		this.context = context;
	}

	@Override
	protected OverlayItem createItem(int i) {
		// TODO Auto-generated method stub
		return mapOverlays.get(i);
	}

	@Override
	public int size() {
		// TODO Auto-generated method stub
		return mapOverlays.size();
	}

	@Override
	protected boolean onTap(int index) {
		OverlayItem item = mapOverlays.get(index);
		AlertDialog.Builder ad = new AlertDialog.Builder(context);
		ad.setTitle(item.getTitle());
		ad.setMessage(item.getSnippet());
		ad.show();
		return true;

	}

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

}

MapMarker.java

package com.map.marker;

import java.util.List;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;
import com.google.android.maps.OverlayItem;
import android.graphics.drawable.Drawable;
import android.os.Bundle;

public class MapMarker extends MapActivity {

	private MapView mapView;

	private static final int latitude1 = -7824269;
	private static final int longitude1 = 110364532;

	private static final int latitude2 = -7822269;
	private static final int longitude2 = 110424532;

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

		mapView = (MapView) findViewById(R.id.map_view);
		mapView.setBuiltInZoomControls(true);

		List<Overlay> mapOverlays = mapView.getOverlays();

		Drawable drawable = this.getResources().getDrawable(R.drawable.marker);

		GeoPoint point = new GeoPoint(latitude1, longitude1);
		GeoPoint point2 = new GeoPoint(latitude2, longitude2);

		OverlayItem overlayitem = new OverlayItem(point, "Hai..", "Saya omayib");
		OverlayItem overlayitem2 = new OverlayItem(point2, "Hai..",
				"Saya Fitri");

		CustomOverlay itemizedOverlay = new CustomOverlay(drawable, this);

		itemizedOverlay.addOverlay(overlayitem);
		itemizedOverlay.addOverlay(overlayitem2);
		mapOverlays.add(itemizedOverlay);

		MapController mapController = mapView.getController();
		mapController.animateTo(point2);
		mapController.setZoom(15);

	}

	@Override
	protected boolean isRouteDisplayed() {
		// TODO Auto-generated method stub
		return false;
	}
}