gwt的這些特性還是很有意思的，感覺比echo更貼近html, 比如說尺寸等數據，寫"20%"和"200px"都可以。echo則盡量封裝的象swing, 屏蔽掉html.

anyway, 對于大多數邏輯都在客戶端的應用，gwt可以大展身手。比如小游戲～

guess number demo看這里：http://steeven.googlepages.com/MyApp.html
完全在瀏覽器上運行的玩意，沒有寫一句js，感覺還是很爽的～

代碼如下：
package?org.steeven.gwt.test.client;

import?com.google.gwt.core.client.EntryPoint;
import?com.google.gwt.user.client.Random;
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.HasHorizontalAlignment;
import?com.google.gwt.user.client.ui.RootPanel;
import?com.google.gwt.user.client.ui.TextBox;
import?com.google.gwt.user.client.ui.VerticalPanel;
import?com.google.gwt.user.client.ui.Widget;

/**
?*?@author?steeven@gmail.com
?*/
public?class?MyApp?implements?EntryPoint?{

????TextBox?txtCount?=?new?TextBox();

????private?Grid?pnlMain;

????private?Button[]?numbers?=?new?Button[100];

????private?int?target;

????private?int?count;

????private?DialogBox?box;

????private?Button?btnRetry;

????private?Button?btnClose;

????/**
?????*?This?is?the?entry?point?method.
?????*/
????public?void?onModuleLoad()?{
????????VerticalPanel?pnlStatus?=?new?VerticalPanel();
????????pnlStatus.setHorizontalAlignment(HasHorizontalAlignment.ALIGN_CENTER);
????????pnlStatus.setSpacing(20);

????????txtCount.setEnabled(false);
????????txtCount.setVisibleLength(10);
????????pnlStatus.add(txtCount);
????????btnRetry?=?new?Button();
????????btnRetry.setHTML("<img?src=\"replay.gif\"/>?<u>R</u>etry");
????????btnRetry.setAccessKey('r');
????????btnRetry.addClickListener(new?ClickListener()?{
????????????public?void?onClick(Widget?sender)?{
????????????????doInit();
????????????}
????????});
????????pnlStatus.add(btnRetry);

????????Button?btnAbout?=?new?Button();
????????btnAbout.setHTML("<img?src='about.gif'/>?<u>A</u>bout");
????????btnAbout.setAccessKey('a');
????????btnAbout.addClickListener(new?ClickListener()?{
????????????public?void?onClick(Widget?sender)?{
????????????????doAbout();
????????????}
????????});
????????pnlStatus.add(btnAbout);

????????RootPanel.get("status").add(pnlStatus);

????????pnlMain?=?new?Grid(10,?10);
????????RootPanel.get("main").add(pnlMain);

????????for?(int?i?=?0;?i?<?100;?i++)?{
????????????numbers[i]?=?new?Button();
????????????numbers[i].setText(i?+?"");
????????????numbers[i].addClickListener(new?ClickListener()?{
????????????????public?void?onClick(Widget?sender)?{
????????????????????doGuess(sender);
????????????????}
????????????});
????????????pnlMain.setWidget(i?/?10,?i?%?10,?numbers[i]);
????????}

????????box?=?new?DialogBox();
????????box.setPopupPosition(400,?200);
????????btnClose?=?new?Button("<u>C</u>lose",?new?ClickListener()?{
????????????public?void?onClick(Widget?sender)?{
????????????????box.hide();
????????????????doInit();
????????????}
????????});
????????btnClose.setAccessKey('c');
????????box.add(btnClose);
????????doInit();
????}

????protected?void?doGuess(Widget?sender)?{
????????Button?btn?=?(Button)?sender;
????????btnRetry.setEnabled(true);
????????int?n?=?Integer.parseInt(btn.getText());
????????txtCount.setText(""?+?(++count));
????????if?(n?==?target)?{
????????????numbers[n].setEnabled(false);
????????????btnClose.setFocus(true);
????????????box.clear();
????????????box
????????????????????.setHTML("<center><img?src='win.gif'/><h1>YOU?WIN!!!</h1><br/><br/><br/>");
????????????box.add(btnClose);
????????????box.show();
????????}?else?{
????????????if?(n?<?target)
????????????????for?(int?i?=?0;?i?<=?n;?i++)
????????????????????numbers[i].setEnabled(false);
????????????else
????????????????for?(int?i?=?n;?i?<?100;?i++)
????????????????????numbers[i].setEnabled(false);
????????}

????}

????protected?void?doAbout()?{
????????box.clear();
????????box
????????????????.setHTML("<img?src='about.gif'/><h1>Guess?Number</h1><h3>Google?web?toolkit?test</h3>");
????????box.add(btnClose);
????????box.show();
????}

????private?void?doInit()?{
????????btnRetry.setEnabled(false);
????????target?=?Random.nextInt(99);
????????count?=?0;
????????txtCount.setText("0");
????????for?(int?i?=?0;?i?<?100;?i++)?{
????????????numbers[i].setVisible(true);
????????????numbers[i].setEnabled(true);
????????}
????}

}

第一次玩gwt, 總共花了3個小時，菜呀