InfoPanel.java

package com.gwt.ui.client;

import java.util.ArrayList;

import com.google.gwt.core.client.GWT;
import com.google.gwt.uibinder.client.UiBinder;
import com.google.gwt.uibinder.client.UiField;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.PopupPanel;
import com.google.gwt.user.client.ui.Widget;


public class InfoPanel extends PopupPanel {

    public static void display(String title, String message) {
        final InfoPanel info = new InfoPanel(title, message);

        info.show();
        
        Timer t = new Timer() {
            @Override
            public void run() {
                info.hide();
            }
        };
        t.schedule(4000);
    }

    @Override
    public void show() {
        super.show();
        slots.add(level, this);
    }


    @Override
    public void hide() {
        super.hide();
        slots.set(level, null);
    }


    protected InfoPanel(String title, String message) {
        this.addStyleName("infoClientPanel");
        add(new InfoWidget(title, message));
        setWidth("300px");
        setHeight("50px");

        @SuppressWarnings("unused")
        int root_width = Window.getClientWidth();
        int root_height = Window.getClientHeight();

        level = findAvailableLevel();

        int left = 25;
        int top = root_height - 100 - (level * 80);

        setPopupPosition(left, top);
    }

    private static ArrayList<InfoPanel> slots = new ArrayList<InfoPanel>();

    private int level;

    private static int findAvailableLevel() {
        int size = slots.size();
        for (int i=0; i<size; i++) {
            if (slots.get(i) == null) {
                return i;
            }
        }
        return size;
    }
    
    public static class InfoWidget extends Composite {
        MyUiBinder binder = GWT.create(MyUiBinder.class);
        interface MyUiBinder extends UiBinder<Widget, InfoWidget> {}
        @UiField
        Label title;
        @UiField
        Label message;
        
        private InfoWidget(String title, String message) {
            initWidget(binder.createAndBindUi(this));
            this.title.setText(title);
            this.message.setText(message);
        }
    }



}