MapItemizedOverlay.java

package com.ushahidi.android.app;

import java.lang.reflect.Method;
import java.util.List;

import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.ViewGroup.LayoutParams;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;
import com.google.android.maps.OverlayItem;
import com.ushahidi.android.app.data.IncidentsData;

/**
 * An abstract extention to the ItemizedOverlay for displaying information on a
 * ballon upon a tap of each marker overlay.
 * 
 * @credits - http://github.com/jgilfelt/android-mapviewballoons/
 * @author Jeff Gilfelt
 */
public abstract class MapItemizedOverlay<Item> extends com.google.android.maps.ItemizedOverlay<OverlayItem> {

    private MapView mapView;

    private BalloonOverlayView balloonView;

    private IncidentMap iMap;

    private List<IncidentsData> mNewIncidents;

    //private Bundle extras;

    private int viewOffset;

    private View clickRegion;

    MapController mc;

    /**
     * @param marker - An icon to be drawn on the map for each item in the
     *            overlay.
     * @param mapView - The map view upon which the overlay item will be drawn.
     */
    public MapItemizedOverlay(Drawable marker, MapView mapView, IncidentMap iMap,
            List<IncidentsData> mNewIncidents, Bundle extras) {

        super(marker);

        this.mapView = mapView;
        this.viewOffset = 32;
        this.iMap = iMap;
        this.mNewIncidents = mNewIncidents;
        //this.extras = extras;
        this.mc = mapView.getController();

    }

    /**
     * Set the horizontal distance between the marker and the bottom of the
     * information balloon. The default is 0 which works well for center bounded
     * markers. If your marker is center-bottom bounded, call this before adding
     * overlay items to ensure the balloon hovers exactly above the marker.
     * 
     * @param pixels - The padding between the center point and the bottom of
     *            the information balloon.
     */
    public void setBalloonBottomOffset(int pixels) {
        viewOffset = pixels;
    }

    /**
     * Override this method to handle a "tap" on a balloon. By default, does
     * nothing and returns false.
     * 
     * @param index - The index of the item whose balloon is tapped.
     * @return true if you handled the tap, otherwise false.
     */
    protected boolean onBalloonTap(int index) {
        return false;
    }

    /*
     * (non-Javadoc)
     * @see com.google.android.maps.ItemizedOverlay#onTap(int)
     */
    @Override
    protected boolean onTap(int index) {
        boolean isRecycled;
        int thisIndex;
        GeoPoint point;
        thisIndex = index;
        
        point = createItem(index).getPoint();

        if (balloonView == null) {

            balloonView = new BalloonOverlayView(this.iMap, mapView.getContext(),
                    viewOffset, this.mNewIncidents, index);
            clickRegion = balloonView.findViewById(R.id.balloon_inner_layout);
            isRecycled = false;

        } else {
            
            isRecycled = true;
        }

        balloonView.setVisibility(View.GONE);

        balloonView.setData(createItem(index),index);
        
        MapView.LayoutParams params = new MapView.LayoutParams(LayoutParams.WRAP_CONTENT,
                LayoutParams.WRAP_CONTENT, point, MapView.LayoutParams.BOTTOM_CENTER);

        params.mode = MapView.LayoutParams.MODE_MAP;

        setBalloonTouchListener(thisIndex);
        balloonView.setVisibility(View.VISIBLE);

        if (isRecycled) {
            balloonView.setLayoutParams(params);
        } else {
            mapView.addView(balloonView, params);
        }

        mc.animateTo(point);
        return true;
    }

    /**
     * Sets the onTouchListener for the balloon being displayed, calling the
     * overridden onBalloonTap if implemented.
     * 
     * @param thisIndex - The index of the item whose balloon is tapped.
     */
    private void setBalloonTouchListener(final int thisIndex) {

        try {
            @SuppressWarnings("unused")
            Method m = this.getClass().getDeclaredMethod("onBalloonTap", int.class);

            clickRegion.setOnTouchListener(new OnTouchListener() {
                public boolean onTouch(View v, MotionEvent event) {

                    View l = ((View)v.getParent()).findViewById(R.id.balloon_main_layout);
                    Drawable d = l.getBackground();

                    if (event.getAction() == MotionEvent.ACTION_DOWN) {
                        int[] states = {
                            android.R.attr.state_pressed
                        };
                        if (d.setState(states)) {
                            d.invalidateSelf();
                        }
                        return true;
                    } else if (event.getAction() == MotionEvent.ACTION_UP) {
                        int newStates[] = {};
                        if (d.setState(newStates)) {
                            d.invalidateSelf();
                        }
                        // call overridden method
                        onBalloonTap(thisIndex);
                        return true;
                    } else {
                        return false;
                    }

                }
            });

        } catch (SecurityException e) {
            return;
        } catch (NoSuchMethodException e) {
            // method not overridden - do nothing
            return;
        }
    }

}