com.google.gwt.demos.gwtcanvas.client.GWTCanvasDemo.java Source code

Introduction

Here is the source code for com.google.gwt.demos.gwtcanvas.client.GWTCanvasDemo.java

Source

/*
 * 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.demos.gwtcanvas.client;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.event.dom.client.ChangeEvent;
import com.google.gwt.event.dom.client.ChangeHandler;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.ListBox;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.widgetideas.graphics.client.GWTCanvas;

import java.util.ArrayList;

/**
 * Simple demo of the GWTCanvas Widget. 
 * 
 * Selection box at top to choose demo.
 * Single shared GWT Canvas in middle.
 * Optional control panel at bottom for demo descriptions
 * and demo UI controls
 * 
 * Entry point classes define <code>onModuleLoad()</code>.
 *
 */
public class GWTCanvasDemo implements EntryPoint {

    /*
     * Single shared canvas for all demos 
     */
    private GWTCanvas canvas;

    private SimpleCanvasDemo currentDemo;

    /*
     * Collection of the demos available
     */
    private ArrayList<SimpleCanvasDemo> demos = new ArrayList<SimpleCanvasDemo>();

    private HorizontalPanel layout;

    public void onModuleLoad() {

        layout = new HorizontalPanel();

        // Each demo will set their own dimensions, so it doesn't matter
        // what we initialize the canvas to.
        canvas = new GWTCanvas(400, 400);

        canvas.addStyleName("gwt-canvas");

        // Create demos
        demos.add(new StaticDemo(canvas));
        demos.add(new LogoDemo(canvas));
        demos.add(new ParticleDemo(canvas));
        demos.add(new GradientDemo(canvas));
        demos.add(new SuiteDemo(canvas));

        // Add them to the selection list box
        ListBox lb = new ListBox();
        lb.setStyleName("listBox");

        for (int i = 0; i < demos.size(); i++) {
            lb.addItem(((SimpleCanvasDemo) demos.get(i)).getName());
        }

        lb.addChangeHandler(new ChangeHandler() {
            public void onChange(ChangeEvent event) {
                int choice = ((ListBox) event.getSource()).getSelectedIndex();
                swapDemo(demos.get(choice));
            }
        });

        // start off with the first demo
        currentDemo = demos.get(0);

        // Add widgets to layout and RootPanel
        VerticalPanel vp = new VerticalPanel();
        vp.add(lb);
        vp.add(canvas);
        layout.add(vp);
        if (currentDemo.getControls() != null) {
            layout.add(currentDemo.getControls());
        }
        RootPanel.get().add(layout);
        currentDemo.drawDemo();
    }

    /*
     * Changes the current demo for the input demo
     */
    private void swapDemo(SimpleCanvasDemo newDemo) {
        currentDemo.stopDemo();
        layout.remove(currentDemo.getControls());
        currentDemo = newDemo;
        layout.add(currentDemo.getControls());
        currentDemo.drawDemo();
    }

}