gistfile1.java

package com.example.maptest;

import java.util.ArrayList;
import java.util.Timer;
import java.util.TimerTask;

import org.osmdroid.DefaultResourceProxyImpl;
import org.osmdroid.util.GeoPoint;
import org.osmdroid.views.MapView;
import org.osmdroid.views.overlay.ItemizedIconOverlay;
import org.osmdroid.views.overlay.OverlayItem;

import android.app.Activity;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.widget.RelativeLayout;
import android.widget.RelativeLayout.LayoutParams;

public class MainActivity extends Activity {

	private static final float DUMMY_LAT = 20.60636f;
	private static final float DUMMY_LON = 8.13008f;
	
	public static final int PULSE_INTERVAL = 20;
	public static final int PULSE_SPEED = 100;

	private OverlayItem overlayItem;
	private MapView osmMapView;
	private ItemizedIconOverlay<OverlayItem> overlayIcon;
	private boolean alphaDirection;
	private int currentOverlayAlpha;

	@Override
	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.activity_main);

		osmMapView = new MapView(this, 256);

		GeoPoint dummyGeoPoint = new GeoPoint(DUMMY_LAT, DUMMY_LON);
		osmMapView.getController().setCenter(dummyGeoPoint);

		Drawable overlayDrawable = getResources().getDrawable(R.drawable.person);

		final ArrayList<OverlayItem> items = new ArrayList<OverlayItem>();
		overlayItem = new OverlayItem("title", "description", dummyGeoPoint);
		
		overlayItem.setMarker(overlayDrawable);
		items.add(overlayItem);
		
		overlayIcon = new ItemizedIconOverlay<OverlayItem>(items, null, new DefaultResourceProxyImpl(getBaseContext()));
		osmMapView.getOverlays().add(overlayIcon);

		addContentView(osmMapView, new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
	
		Timer timer = new Timer();
	        alphaDirection = true;
	        currentOverlayAlpha = 0;

		timer.schedule(new TimerTask() {
			@Override
			public void run() {
				runOnUiThread(new Runnable() {
					@Override
					public void run() {
						if (currentOverlayAlpha > 255) {
							currentOverlayAlpha = 255;
							alphaDirection = !alphaDirection;
						} else if (currentOverlayAlpha < 0) {
							currentOverlayAlpha = 0;
							alphaDirection = !alphaDirection;
						}
						
						// first remove the current overlay icon from map view
						osmMapView.getOverlays().remove(overlayIcon);
						osmMapView.invalidate();
						
						// set the new alpha to the overlayDrawable
						Drawable overlayDrawable = overlayItem.getDrawable();
						overlayDrawable.setAlpha(currentOverlayAlpha);
						overlayItem.setMarker(overlayDrawable);

						// add the overlay item with the new alpha to map view
						overlayIcon.removeAllItems();
						overlayIcon.addItem(overlayItem);
						osmMapView.getOverlays().add(overlayIcon);
						
						if (alphaDirection) {
							currentOverlayAlpha += PULSE_INTERVAL;
						} else {
							currentOverlayAlpha -= PULSE_INTERVAL;	
						}
					}
				});
			}
		}, PULSE_SPEED, PULSE_SPEED);
	}

}