Java tutorial
/* * Copyright 2011 SWM Services GmbH. * * 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 de.swm.commons.mobile.client.orientation; import com.google.gwt.core.client.GWT; import com.google.gwt.core.client.JavaScriptObject; import com.google.gwt.event.logical.shared.CloseEvent; import com.google.gwt.event.logical.shared.CloseHandler; import com.google.gwt.event.logical.shared.ResizeEvent; import com.google.gwt.event.logical.shared.ResizeHandler; import com.google.gwt.event.shared.EventBus; import com.google.gwt.event.shared.HandlerRegistration; import com.google.gwt.event.shared.SimpleEventBus; import com.google.gwt.user.client.Window; import de.swm.commons.mobile.client.SWMMobile; import java.util.logging.Logger; /** * Controller that supports orientation changes. * */ public class OrientationController { private static final Logger LOGGER = Logger.getLogger(OrientationChangeHandler.class.getName()); private static final int DEGREES_90 = 90; private static final int DEGREES_180 = 180; private static Orientation currentOrientation; private static JavaScriptObject nativeJsFunction; private static final EventBus MANAGER = new SimpleEventBus(); static { if (GWT.isClient()) { setupOrientation(); } } /** * Add a orientation handler to detect the device orientation * * @param handler * the handler to add {@link OrientationChangeHandler} . * @return a {@link com.google.gwt.event.shared.HandlerRegistration} object. */ public static HandlerRegistration addOrientationChangeHandler(OrientationChangeHandler handler) { return MANAGER.addHandler(OrientationChangeEvent.getType(), handler); } /** * Get the current orientation of the device * * @return the current orientation of the device */ public static Orientation getOrientation() { if (!orientationSupport()) { int height = Window.getClientHeight(); int width = Window.getClientWidth(); if (width > height) { return Orientation.LANDSCAPE; } else { return Orientation.PORTRAIT; } } else { int orientation = testBrowserOrientationSupport(); Orientation o; switch (orientation) { case 0: case DEGREES_180: o = Orientation.PORTRAIT; break; case DEGREES_90: case -DEGREES_90: o = Orientation.LANDSCAPE; break; default: throw new IllegalStateException("this should not happen!?"); } return o; } } /** * Fires an orientation change event to the event bus. * * @param orientation * the orientation */ private static void fireOrientationChangedEvent(Orientation orientation) { MANAGER.fireEvent(new OrientationChangeEvent(orientation)); } /** * Will test if the browser supports orientation events natively. * * @return true is supported. */ private static native int testBrowserOrientationSupport()/*-{ if (typeof ($wnd.orientation) == 'undefined') { return 0; } return $wnd.orientation; }-*/; /** * Will be called when the orientation will change. * * @param orientation * orientation value in degrees */ private static void onorientationChange(int orientation) { Orientation o; switch (orientation) { case 0: case DEGREES_180: o = Orientation.PORTRAIT; break; case DEGREES_90: case -DEGREES_90: o = Orientation.LANDSCAPE; break; default: LOGGER.info("on orientation changed called with invalid value: '" + orientation + "' - defaulting to Portrait"); o = Orientation.PORTRAIT; break; } currentOrientation = o; fireOrientationChangedEvent(o); } /** * Determine if the device provides Orientation support * * @return true if provided. */ private static boolean orientationSupport() { return SWMMobile.getOsDetection().isIPad() || SWMMobile.getOsDetection().isIPhone(); } /** * Set up orientation support. */ private static void setupOrientation() { if (!orientationSupport()) { Window.addResizeHandler(new ResizeHandler() { @Override public void onResize(ResizeEvent event) { Orientation orientation = getOrientation(); if (orientation != currentOrientation) { currentOrientation = orientation; fireOrientationChangedEvent(orientation); } } }); } else { nativeJsFunction = setupBrowserNativeOrientationSupport(); Window.addCloseHandler(new CloseHandler<Window>() { @Override public void onClose(CloseEvent<Window> event) { destroyOrientation(nativeJsFunction); } }); } } /** * Will register an orientation change handler to support native browser orientation cahnge event. * * @return true if supported */ private static native JavaScriptObject setupBrowserNativeOrientationSupport()/*-{ var func = $entry(function() { @de.swm.commons.mobile.client.orientation.OrientationController::onorientationChange(I)($wnd.orientation); }); $doc.body.onorientationchange = func; $doc.addEventListener("orientationChanged", func); return func; }-*/; /** * Unregister all orientation change events. * * @param o * the js-event handler. */ private static native void destroyOrientation(JavaScriptObject o)/*-{ $doc.body.onorientationchange = null; $doc.removeEventListener("orientationChanged", o); }-*/; }