ItemizedLayer.java

/*
 * Copyright 2012 osmdroid authors: Nicolas Gramlich, Theodore Hong, Fred Eisele
 * 
 * Copyright 2013 Hannes Janetzek
 *
 * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
 *
 * This program is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.oscim.layers.marker;

import java.util.ArrayList;
import java.util.List;

import org.oscim.core.BoundingBox;
import org.oscim.core.Point;
import org.oscim.event.Gesture;
import org.oscim.event.GestureListener;
import org.oscim.event.MotionEvent;
import org.oscim.map.Map;
import org.oscim.map.Viewport;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ItemizedLayer<Item extends MarkerItem> extends MarkerLayer<Item>
        implements GestureListener {

	static final Logger log = LoggerFactory.getLogger(ItemizedLayer.class);

	protected final List<Item> mItemList;
	protected final Point mTmpPoint = new Point();
	protected OnItemGestureListener<Item> mOnItemGestureListener;
	protected int mDrawnItemsLimit = Integer.MAX_VALUE;

	public ItemizedLayer(Map map, MarkerSymbol defaulMarker) {
		this(map, new ArrayList<Item>(), defaulMarker, null);
	}

	public ItemizedLayer(Map map, List<Item> list,
	        MarkerSymbol defaultMarker,
	        OnItemGestureListener<Item> listener) {

		super(map, defaultMarker);

		mItemList = list;
		mOnItemGestureListener = listener;
		populate();
	}

	public void setOnItemGestureListener(OnItemGestureListener<Item> listener) {
		mOnItemGestureListener = listener;
	}

	@Override
	protected Item createItem(int index) {
		return mItemList.get(index);
	}

	@Override
	public int size() {
		return Math.min(mItemList.size(), mDrawnItemsLimit);
	}

	public boolean addItem(Item item) {
		final boolean result = mItemList.add(item);
		populate();
		return result;
	}

	public void addItem(int location, Item item) {
		mItemList.add(location, item);
	}

	public boolean addItems(List<Item> items) {
		final boolean result = mItemList.addAll(items);
		populate();
		return result;
	}

	public void removeAllItems() {
		removeAllItems(true);
	}

	public void removeAllItems(boolean withPopulate) {
		mItemList.clear();
		if (withPopulate) {
			populate();
		}
	}

	public boolean removeItem(Item item) {
		final boolean result = mItemList.remove(item);
		populate();
		return result;
	}

	public Item removeItem(int position) {
		final Item result = mItemList.remove(position);
		populate();
		return result;
	}

	/**
	 * Each of these methods performs a item sensitive check. If the item is
	 * located its corresponding method is called. The result of the call is
	 * returned. Helper methods are provided so that child classes may more
	 * easily override behavior without resorting to overriding the
	 * ItemGestureListener methods.
	 */
	//	@Override
	//	public boolean onTap(MotionEvent event, MapPosition pos) {
	//		return activateSelectedItems(event, mActiveItemSingleTap);
	//	}

	protected boolean onSingleTapUpHelper(int index, Item item) {
		return mOnItemGestureListener.onItemSingleTapUp(index, item);
	}

	private final ActiveItem mActiveItemSingleTap = new ActiveItem() {
		@Override
		public boolean run(int index) {
			final ItemizedLayer<Item> that = ItemizedLayer.this;
			if (mOnItemGestureListener == null) {
				return false;
			}
			return onSingleTapUpHelper(index, that.mItemList.get(index));
		}
	};

	protected boolean onLongPressHelper(int index, Item item) {
		return this.mOnItemGestureListener.onItemLongPress(index, item);
	}

	private final ActiveItem mActiveItemLongPress = new ActiveItem() {
		@Override
		public boolean run(final int index) {
			final ItemizedLayer<Item> that = ItemizedLayer.this;
			if (that.mOnItemGestureListener == null) {
				return false;
			}
			return onLongPressHelper(index, that.mItemList.get(index));
		}
	};

	/**
	 * When a content sensitive action is performed the content item needs to be
	 * identified. This method does that and then performs the assigned task on
	 * that item.
	 * 
	 * @return true if event is handled false otherwise
	 */
	protected boolean activateSelectedItems(MotionEvent event, ActiveItem task) {
		int size = mItemList.size();
		if (size == 0)
			return false;

		int eventX = (int) event.getX() - mMap.getWidth() / 2;
		int eventY = (int) event.getY() - mMap.getHeight() / 2;
		Viewport mapPosition = mMap.viewport();

		BoundingBox bbox = mapPosition.getBBox(128);

		int nearest = -1;
		int inside = -1;
		double insideY = -Double.MAX_VALUE;

		/* squared dist: 50*50 pixel ~ 2mm on 400dpi */
		double dist = 2500;

		for (int i = 0; i < size; i++) {
			Item item = mItemList.get(i);

			if (!bbox.contains(item.geoPoint))
				continue;

			mapPosition.toScreenPoint(item.getPoint(), mTmpPoint);

			float dx = (float) (mTmpPoint.x - eventX);
			float dy = (float) (mTmpPoint.y - eventY);

			MarkerSymbol it = item.getMarker();
			if (it == null)
				it = mMarkerRenderer.mDefaultMarker;

			if (it.isInside(dx, dy)) {
				if (mTmpPoint.y > insideY) {
					insideY = mTmpPoint.y;
					inside = i;
				}
			}
			if (inside >= 0)
				continue;

			double d = dx * dx + dy * dy;
			if (d > dist)
				continue;

			dist = d;
			nearest = i;
		}

		if (inside >= 0)
			nearest = inside;

		if (nearest >= 0 && task.run(nearest)) {
			mMarkerRenderer.update();
			mMap.render();
			return true;
		}
		return false;
	}

	/**
	 * When the item is touched one of these methods may be invoked depending on
	 * the type of touch. Each of them returns true if the event was completely
	 * handled.
	 */
	public static interface OnItemGestureListener<T> {
		public boolean onItemSingleTapUp(int index, T item);

		public boolean onItemLongPress(int index, T item);
	}

	public static interface ActiveItem {
		public boolean run(int aIndex);
	}

	@Override
	public boolean onGesture(Gesture g, MotionEvent e) {
		if (g instanceof Gesture.Tap)
			return activateSelectedItems(e, mActiveItemSingleTap);

		if (g instanceof Gesture.LongPress)
			return activateSelectedItems(e, mActiveItemLongPress);

		return false;
	}

	public Item getByUid(Object uid) {
		for (Item it : mItemList)
			if (it.getUid() == uid)
				return it;

		return null;
	}
}