MobileKeyboard.java

package ch.unifr.pai.twice.mousecontrol.client;

/*
 * Copyright 2013 Oliver Schmid
 * 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.
 */
import java.util.Date;

import com.google.gwt.dom.client.Style.Unit;
import com.google.gwt.dom.client.Style.VerticalAlign;
import com.google.gwt.event.dom.client.BlurEvent;
import com.google.gwt.event.dom.client.BlurHandler;
import com.google.gwt.event.dom.client.FocusEvent;
import com.google.gwt.event.dom.client.FocusHandler;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.Event.NativePreviewEvent;
import com.google.gwt.user.client.Event.NativePreviewHandler;
import com.google.gwt.user.client.ui.TextBox;

/**
 * Implementation for triggering the keyboard through a "button".
 * 
 * @author Oliver Schmid
 * 
 */
public class MobileKeyboard extends TextBox {

	private StringBuilder log = new StringBuilder();

	private HandlerRegistration registration;

	/**
	 * Add information to the log
	 * 
	 * @param name
	 * @param message
	 * @param attributes
	 */
	private void addToLog(String name, String message, String attributes) {
		log.append("<").append(name);
		log.append(" time=\"");
		log.append(new Date().getTime());
		log.append("\">");
		if (message != null)
			log.append(message);
		log.append("</").append(name).append(">");
	}

	/**
	 * Event handler listening for key events
	 */
	private final NativePreviewHandler handler = new NativePreviewHandler() {

		@Override
		public void onPreviewNativeEvent(NativePreviewEvent event) {
			switch (event.getTypeInt()) {
				case Event.ONKEYDOWN:
					addToLog("keydown", null, null);
					break;
				case Event.ONKEYUP:
					addToLog("keyup", null, null);
					break;
				case Event.ONKEYPRESS:
					addToLog("keypress", null, null);
					break;
			}
		}
	};

	public MobileKeyboard() {
		this(null, null);
	}

	/**
	 * The mobile keyboard widget
	 * 
	 * @param openKeyboardText
	 *            - the text for the open keyboard button
	 * @param closeKeyboardText
	 *            - the text for the close keyboard button
	 */
	public MobileKeyboard(String openKeyboardText, String closeKeyboardText) {
		super();
		// Prevent IPhone and IPad to write everything in upper case
		getElement().setAttribute("autocapitalize", "off");
		setWidth("100%");
		setHeight("100%");
		getElement().getStyle().setFontSize(200, Unit.PCT);
		setAlignment(TextAlignment.CENTER);
		getElement().getStyle().setVerticalAlign(VerticalAlign.TOP);
		addFocusHandler(new FocusHandler() {

			/**
			 * If the text box gets focus, add the handler
			 * 
			 * @see com.google.gwt.event.dom.client.FocusHandler#onFocus(com.google.gwt.event.dom.client.FocusEvent)
			 */
			@Override
			public void onFocus(FocusEvent event) {
				getElement().getStyle().setZIndex(-1);
				registration = Event.addNativePreviewHandler(handler);
				// Scheduler.get().scheduleDeferred(new ScheduledCommand() {
				//
				// @Override
				// public void execute() {
				// Window.scrollTo(0, 1);
				// Document.get().setScrollTop(0);
				// RootLayoutPanel.get().onResize();
				// }
				// });
			}
		});
		addBlurHandler(new BlurHandler() {

			/**
			 * If the text box looses focus, hide the keyboard
			 * 
			 * @see com.google.gwt.event.dom.client.BlurHandler#onBlur(com.google.gwt.event.dom.client.BlurEvent)
			 */
			@Override
			public void onBlur(BlurEvent event) {
				hide();
			}
		});
		setValue(openKeyboardText);
		getElement().getStyle().setZIndex(2);
	}

	/**
	 * Stop the execution of the keyboard
	 */
	public void stop() {
		log = new StringBuilder();
		hide();
	}

	/**
	 * Hide the keyboard (and remove the handlers)
	 */
	private void hide() {
		getElement().getStyle().setZIndex(2);
		if (registration != null)
			registration.removeHandler();
		registration = null;
	}

	/**
	 * Start the execution of the keyboard (which is in hidden mode)
	 */
	public void start() {
		hide();
	}

}