Google Web Toolkit - Simple Example

The Google Web Toolkit (GWT) is a framework that allows for web development using Java. The framework will convert the Java code into html/javascript.

This approach makes developing and debugging feature rich clients much easier than writing javascript yourself.

To get familiar with the framework I wrote a simple getting started app inspired from the GWT docs. It simply creates a button, label and grid.

It adds an event to the button to hide the label. Also adds a TableListener to the grid. I use this to capture cell clicks and popup a dialog.

Reading the docs you can then style this using css with the following attributes:

    *  .gwt-DialogBox { the outside of the dialog }
    * .gwt-DialogBox .Caption { the caption }

/*
 * mcintoshEntryPoint.java
 *
 * Created on June 29, 2008, 1:46 PM
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */
package com.client;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.ClickListener;
import com.google.gwt.user.client.ui.DialogBox;
import com.google.gwt.user.client.ui.Grid;
import com.google.gwt.user.client.ui.HTMLTable;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.PopupPanel;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.SourcesTableEvents;
import com.google.gwt.user.client.ui.TableListener;
import com.google.gwt.user.client.ui.Widget;

/**
 *
 * @author avalanche
 */
public class mcintoshEntryPoint implements EntryPoint {

    /** Creates a new instance of mcintoshEntryPoint */
    public mcintoshEntryPoint() {
    }

    private static class MyDialog extends DialogBox {

        public MyDialog(String text) {
            // Set the dialog box's caption.
            setText(text);

            // DialogBox is a SimplePanel, so you have to set its widget property to
            // whatever you want its contents to be.
            Button ok = new Button("OK");
            ok.addClickListener(new ClickListener() {

                public void onClick(Widget sender) {
                    MyDialog.this.hide();
                }
                });
            setWidget(ok);
        }
        }

    /**
     * The entry point method, called automatically by loading a module
     * that declares an implementing class as an entry-point
     */
    public void onModuleLoad() {
        final Label label = new Label("Hello, Chris!!!");
        final Button button = new Button("Click me!");
        final HTMLTable table = new Grid(5, 5);
        // Put some values in the grid cells.
        for (int row = 0; row < 5; ++row) {
            for (int col = 0; col < 5; ++col) {
                table.setText(row, col, "" + row + ", " + col);
            }
        }

        button.addClickListener(new ClickListener() {

            public void onClick(Widget w) {
                label.setVisible(!label.isVisible());
            }
            });

        table.addTableListener(new TableListener() {

            public void onCellClicked(SourcesTableEvents arg0, int arg1, int arg2) {
                new MyDialog("You clicked" + arg1 + "," + arg2).show();
            }
            });



        RootPanel.get().add(button);
        RootPanel.get().add(label);
        RootPanel.get().add(table);
    }
    }