/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.maps.client.overlay;
import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.maps.client.event.GroundOverlayVisibilityChangedHandler;
import com.google.gwt.maps.client.event.GroundOverlayVisibilityChangedHandler.GroundOverlayVisibilityChangedEvent;
import com.google.gwt.maps.client.geom.LatLngBounds;
import com.google.gwt.maps.client.impl.GroundOverlayImpl;
import com.google.gwt.maps.client.impl.HandlerCollection;
import com.google.gwt.maps.client.impl.MapEvent;
import com.google.gwt.maps.client.impl.EventImpl.BooleanCallback;
import com.google.gwt.maps.client.overlay.Overlay.ConcreteOverlay;
/**
* A rectangular image overlay whose boundaries are defined by a
* {@link LatLngBounds}.
*
* Example:
*
* <pre>
* MapWidget map; = ...;
* Overlay overlay = new GroundOverlay(<i>url</i>, <i>bounds</i>);
* map.addOverlay(overlay);
* </pre>
*
* TODO: more complete example
*
* @see com.google.gwt.maps.client.MapWidget#addOverlay(Overlay)
*/
public final class GroundOverlay extends ConcreteOverlay {
static GroundOverlay createPeer(JavaScriptObject jsoPeer) {
return new GroundOverlay(jsoPeer);
}
private HandlerCollection<GroundOverlayVisibilityChangedHandler> groundOverlayVisibilityChangedHandlers;
/**
* Creates a new ground overlay from the given image with the specified size.
*
* @param imageUrl the URL of the overlay image
* @param bounds the rectangle defining the bounds of the overlay
*/
public GroundOverlay(String imageUrl, LatLngBounds bounds) {
super(GroundOverlayImpl.impl.construct(imageUrl, bounds));
}
private GroundOverlay(JavaScriptObject jsoPeer) {
super(jsoPeer);
}
/**
* This event is fired when the visibility of the ground overlay is changed (i.e. the
* visibility is flipped from visible to hidden or vice-versa). The
* <code>visible</code> parameter refers to the state of the ground overlay after
* the visibility change has happened.
*
* @param handler the handler to call when this event fires.
*/
public void addGroundOverlayVisibilityChangedHandler(
final GroundOverlayVisibilityChangedHandler handler) {
maybeInitGroundOverlayVisibilityChangeHandlers();
groundOverlayVisibilityChangedHandlers.addHandler(handler, new BooleanCallback() {
@Override
public void callback(boolean visible) {
GroundOverlayVisibilityChangedEvent e = new GroundOverlayVisibilityChangedEvent(
GroundOverlay.this, visible);
handler.onVisibilityChanged(e);
}
});
}
/**
* Returns <code>true</code> if the overlay is currently visible.
* @return <code>true</code> if the overlay is currently visible.
*/
public boolean isVisible() {
return !GroundOverlayImpl.impl.isHidden(jsoPeer);
}
/**
* Removes a single handler of this map previously added with
* {@link GroundOverlay#addGroundOverlayVisibilityChangedHandler(GroundOverlayVisibilityChangedHandler)}.
*
* @param handler the handler to remove
*/
public void removeGroundOverlayVisibilityChangedHandler(
GroundOverlayVisibilityChangedHandler handler) {
if (groundOverlayVisibilityChangedHandlers != null) {
groundOverlayVisibilityChangedHandlers.removeHandler(handler);
}
}
/**
* Sets the overlay visible by passing <code>true</code> or hide it b passing <code>false</code>.
* @param enabled sets the overlay visible by passing <code>true</code> or hide it b passing <code>false</code>.
*/
public void setVisible(boolean enabled) {
if (enabled) {
GroundOverlayImpl.impl.show(jsoPeer);
} else {
GroundOverlayImpl.impl.hide(jsoPeer);
}
}
/**
* Manually trigger the specified event on this object.
*
* Note: The trigger() methods are provided for unit testing purposes only.
*
* @param event an event to deliver to the handler.
*/
void trigger(GroundOverlayVisibilityChangedEvent event) {
maybeInitGroundOverlayVisibilityChangeHandlers();
groundOverlayVisibilityChangedHandlers.trigger(event.isVisible());
}
/**
* Lazy init the HandlerCollection.
*/
private void maybeInitGroundOverlayVisibilityChangeHandlers() {
if (groundOverlayVisibilityChangedHandlers == null) {
groundOverlayVisibilityChangedHandlers = new HandlerCollection<GroundOverlayVisibilityChangedHandler>(
jsoPeer, MapEvent.VISIBILITYCHANGED);
}
}
}