MfMapView.java

package cgeo.geocaching.maps.mapsforge.v6;

import cgeo.geocaching.location.Geopoint;
import cgeo.geocaching.location.Viewport;
import cgeo.geocaching.maps.MapMode;
import cgeo.geocaching.maps.interfaces.OnMapDragListener;
import cgeo.geocaching.settings.Settings;
import cgeo.geocaching.utils.Log;

import android.annotation.SuppressLint;
import android.content.Context;
import android.util.AttributeSet;
import android.view.GestureDetector;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.MotionEvent;

import org.mapsforge.core.model.LatLong;
import org.mapsforge.core.model.Point;
import org.mapsforge.core.util.MercatorProjection;
import org.mapsforge.map.android.view.MapView;

public class MfMapView extends MapView {

    private final GestureDetector gestureDetector;
    private OnMapDragListener onDragListener;

    public MfMapView(final Context context, final AttributeSet attributeSet) {
        super(context, attributeSet);

        gestureDetector = new GestureDetector(context, new GestureListener());
    }

    public Viewport getViewport() {
        final LatLong center = getModel().mapViewPosition.getCenter();
        return new Viewport(new Geopoint(center.latitude, center.longitude), getLatitudeSpan(), getLongitudeSpan());
    }

    public double getLatitudeSpan() {

        double span = 0;

        final long mapSize = MercatorProjection.getMapSize(getModel().mapViewPosition.getZoomLevel(), getModel().displayModel.getTileSize());
        final Point center = MercatorProjection.getPixelAbsolute(getModel().mapViewPosition.getCenter(), mapSize);

        if (getHeight() > 0) {

            try {
                final LatLong low = MercatorProjection.fromPixels(center.x, center.y - getHeight() / 2, mapSize);
                final LatLong high = MercatorProjection.fromPixels(center.x, center.y + getHeight() / 2, mapSize);

                span = Math.abs(high.latitude - low.latitude);
            } catch (final IllegalArgumentException ex) {
                Log.w("Exception when calculating latitude span", ex);
            }
        }

        return span;
    }

    public double getLongitudeSpan() {

        double span = 0;

        final long mapSize = MercatorProjection.getMapSize(getModel().mapViewPosition.getZoomLevel(), getModel().displayModel.getTileSize());
        final Point center = MercatorProjection.getPixelAbsolute(getModel().mapViewPosition.getCenter(), mapSize);

        if (getWidth() > 0) {
            try {
                final LatLong low = MercatorProjection.fromPixels(center.x - getWidth() / 2, center.y, mapSize);
                final LatLong high = MercatorProjection.fromPixels(center.x + getWidth() / 2, center.y, mapSize);

                span = Math.abs(high.longitude - low.longitude);
            } catch (final IllegalArgumentException ex) {
                Log.w("Exception when calculating longitude span", ex);
            }
        }

        return span;
    }

    public int getMapZoomLevel() {
        return getModel().mapViewPosition.getZoomLevel() + 3;
    }

    public void setMapZoomLevel(final int zoomLevel) {
        getModel().mapViewPosition.setZoomLevel((byte) (zoomLevel - 3));
    }

    public void zoomToViewport(final Viewport viewport) {

        if (viewport.bottomLeft.equals(viewport.topRight)) {
            setMapZoomLevel(Settings.getMapZoom(MapMode.SINGLE));
        } else {
            final int tileSize = getModel().displayModel.getTileSize();
            final long mapSize = MercatorProjection.getMapSize((byte) 0, tileSize);
            final double dxMax = MercatorProjection.longitudeToPixelX(viewport.getLongitudeMax(), mapSize) / tileSize;
            final double dxMin = MercatorProjection.longitudeToPixelX(viewport.getLongitudeMin(), mapSize) / tileSize;
            final double zoomX = Math.floor(-Math.log(3.8) * Math.log(Math.abs(dxMax - dxMin)) + getWidth() / tileSize);
            final double dyMax = MercatorProjection.longitudeToPixelX(viewport.getLatitudeMax(), mapSize) / tileSize;
            final double dyMin = MercatorProjection.longitudeToPixelX(viewport.getLatitudeMin(), mapSize) / tileSize;
            final double zoomY = Math.floor(-Math.log(3.8) * Math.log(Math.abs(dyMax - dyMin)) + getHeight() / tileSize);
            final byte newZoom = (byte) Math.min(zoomX, zoomY);
            getModel().mapViewPosition.setZoomLevel(newZoom);
        }
        getModel().mapViewPosition.setCenter(new LatLong(viewport.getCenter().getLatitude(), viewport.getCenter().getLongitude()));
    }

    @SuppressLint("ClickableViewAccessibility")
    @Override
    public boolean onTouchEvent(final MotionEvent ev) {
        gestureDetector.onTouchEvent(ev);
        return super.onTouchEvent(ev);
    }

    private class GestureListener extends SimpleOnGestureListener {
        @Override
        public boolean onDoubleTap(final MotionEvent e) {
            if (onDragListener != null) {
                onDragListener.onDrag();
            }
            return true;
        }

        @Override
        public boolean onScroll(final MotionEvent e1, final MotionEvent e2,
                final float distanceX, final float distanceY) {
            if (onDragListener != null) {
                onDragListener.onDrag();
            }
            return super.onScroll(e1, e2, distanceX, distanceY);
        }
    }

    public void setOnMapDragListener(final OnMapDragListener onDragListener) {
        this.onDragListener = onDragListener;
    }
}