Java tutorial
/* * 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.gears.sample.workerpooldemo.client; import com.google.gwt.animation.client.Animation; import com.google.gwt.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.user.client.ui.AbsolutePanel; import com.google.gwt.user.client.ui.Button; import com.google.gwt.user.client.ui.Composite; import com.google.gwt.user.client.ui.HTML; import com.google.gwt.user.client.ui.HasHorizontalAlignment; import com.google.gwt.user.client.ui.HorizontalPanel; import com.google.gwt.user.client.ui.Image; import com.google.gwt.user.client.ui.VerticalPanel; import com.google.gwt.user.client.ui.Widget; /** * A class that creates a little animation window. */ public class AnimationToy extends Composite { /** * A custom animation that moves a small image around a circle in an * {@link AbsolutePanel}. * * (Ripped from the GWT Showcase demo) */ public class CustomAnimation extends Animation { /** * The x-coordinate of the center of the circle. */ private int centerX = 60; /** * The y-coordinate of the center of the circle. */ private int centerY = 60; /** * The radius of the circle. */ private int radius = 50; protected CustomAnimation(int radius) { this.radius = radius; this.centerX = this.centerY = radius + 10; } @Override protected void onComplete() { super.onComplete(); startButton.setEnabled(true); cancelButton.setEnabled(false); } @Override protected void onStart() { super.onStart(); startButton.setEnabled(false); cancelButton.setEnabled(true); } @Override protected void onUpdate(double progress) { double radian = 2 * Math.PI * progress; updatePosition(animateeLeft, radian, 0); updatePosition(animateeBottom, radian, 0.5 * Math.PI); updatePosition(animateeRight, radian, Math.PI); updatePosition(animateeTop, radian, 1.5 * Math.PI); } /** * Update the position of the widget, adding a rotational offset. * * @param w the widget to move * @param radian the progress in radian * @param offset the offset in radian */ private void updatePosition(Widget w, double radian, double offset) { radian += offset; double x = radius * Math.cos(radian) + centerX; double y = radius * Math.sin(radian) + centerY; absolutePanel.setWidgetPosition(w, (int) x, (int) y); } } /** * The absolute panel used in the example. */ private AbsolutePanel absolutePanel = null; /** * The widget that is being animated. */ private Widget animateeBottom = null; /** * The widget that is being animated. */ private Widget animateeLeft = null; /** * The widget that is being animated. */ private Widget animateeRight = null; /** * The widget that is being animated. */ private Widget animateeTop = null; /** * The instance of an animation. */ private CustomAnimation animation = null; /** * The {@link Button} used to cancel the {@link Animation}. */ private Button cancelButton = null; /** * The {@link Button} used to start the {@link Animation}. */ private Button startButton = null; /** * Constructor. */ public AnimationToy() { initWidget(initialize()); } /** * Initialize this example. */ private Widget initialize() { // Create a new panel absolutePanel = new AbsolutePanel(); // Add a widget that we will animate animateeTop = new Image("gwtLogoThumb.png"); animateeBottom = new Image("gwtLogoThumb.png"); animateeLeft = new Image("gwtLogoThumb.png"); animateeRight = new Image("gwtLogoThumb.png"); absolutePanel.add(animateeTop); absolutePanel.add(animateeBottom); absolutePanel.add(animateeLeft); absolutePanel.add(animateeRight); // Wrap the absolute panel in a DecoratorPanel VerticalPanel absolutePanelWrapper = new VerticalPanel(); absolutePanelWrapper.add(absolutePanel); // Add the components to a panel and return it absolutePanelWrapper.add(createOptionsBar()); // Create the custom animation animation = new CustomAnimation(70); // Set the start position of the widgets animation.onComplete(); absolutePanel.setSize((animation.centerX * 2 + 10) + "px", (animation.centerY * 2 + 10) + "px"); // Return the layout return absolutePanelWrapper; } /** * Create an options panel that allows users to select a widget and reposition * it. * * @return the new options panel */ private Widget createOptionsBar() { // Create a panel to move components around HorizontalPanel optionsBar = new HorizontalPanel(); optionsBar.setSpacing(5); optionsBar.setHorizontalAlignment(HasHorizontalAlignment.ALIGN_CENTER); // Add a title optionsBar.add(new HTML("<b>Animate Logos</b>")); // Add start button startButton = new Button("Start"); startButton.addClickHandler(new ClickHandler() { public void onClick(ClickEvent event) { animation.run(2000); } }); optionsBar.add(startButton); // Add cancel button cancelButton = new Button("Cancel"); cancelButton.addClickHandler(new ClickHandler() { public void onClick(ClickEvent event) { animation.cancel(); } }); optionsBar.add(cancelButton); // Return the options bar return optionsBar; } }