多页教程在谷歌Web工具包（GWT）多页教程在谷歌Web工具包（GWT）(Multiple page

2019-05-14 05:58发布

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我欲成王，谁敢阻挡

女 | 书童

私信

我刚开始学习谷歌Web工具包（GWT）。如何使我的GWT应用程序不同的HTML页面？

例如，我想创建一个书店的应用程序。在这个应用程序，我将有三个页面：

主页在那里我会欢迎各用户，并为用户提供书籍
页面类别和查看详细信息浏览书籍（使用GWT小部件）
检查出的书在网上。

当然也有可能是其他页面，如用户的详细信息，添加新的书籍等，所以，什么是GWT制作不同的页面的最佳途径，如何才能让导航一页一页地？是否有任何例子或教程？还是我甚至需要创建不同的页面时，我可以在一个页面中创建一个整个应用程序？

Answer 1:

我最常做在这样的情况下是首先设计网页框架。我要为头，侧菜单和页脚一个div。我也将有一个div在我的HTML为主要内容。

例：

<html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <meta name='gwt:module' content='org.project.package.Core=org.project.package.Core'>
    </head>
    <body>
        <!-- Load the JavaScript code for GWT -->
        <script language="javascript" src="ui/org.project.package.ui.Core.nocache.js"></script>

        <!-- For some unknown reason in Internet Explorer you have to have cellpadding/spacing ON THE ELEMENT and not on the STYLE if it is in the body tag like this -->
        <table id="wrapper" cellpadding="0" cellspacing="0" style="width: 100%;height: 100%;">

             <!-- Header row -->
             <tr style="height: 25%;">
                 <td colspan="2" id="header"></td>
             </tr>

             <!-- Body row and left nav row -->
             <tr style="height: 65%;">
                 <td id="leftnav"></td>
                 <td id="content"></td>
             </tr>

             <!-- Footer row -->
             <tr style="height: 10%;">
                <td colspan="2" id="footer"></td>
             </tr>

        </table>

        <!-- This iframe handles history -->
        <iframe id="__gwt_historyFrame" style="width:0;height:0;border:0"></iframe>
    </body>
</html>

（如果你喜欢<div>的基础布局，随意使用这些来代替。）

然后你建立你的入口点（在我的情况Core.java ）像往常一样，设置每个元素如需要的话。

RootPanel.get("header").add(new Header());
RootPanel.get("leftnav").add(new NavigationMenu());
RootPanel.get("footer").add(new Footer());

这是当然，可能有一个静态页脚和头，但那是不伦不类。

我也有一个所谓的“内容”抽象类。内容对象延伸“综合”，将有简化的新页面的创建和布局的各种方法。我建立该程序的每一页，无论是一个帮助屏幕，搜索屏幕，购物车，或者别的，就是类型的Content 。

现在，我要做的就是创建一个名为“ContentContainer”级。这是一个单身是负责管理“内容”的元素。它有一个方法“setContent”接受类型为“内容”的对象。然后，它基本上是“内容” <TD>中删除任何东西，与任何部件（复合）您通过“setContent”的方法分配来替换它。该setContent方法也处理历史和标题栏管理。基本上ContentContainer用于聚合的结合，你可能不得不作出是否每一页的内容必须“知道”它必须执行的所有功能都不同点。

最后，您需要一种方式来获得该网页，对不对？这很简单：

ContentContainer.getInstance().setContent(new Search());

把上面在上单击事件的地方，你是金色的。

你的其他部件唯一需要的东西绑定到是ContentContainer和内容，他们添加的类型。

我可以看到ChrisBo的方法的缺点是，你已经得到了必须保持标记列表 - >页面。另一个缺点我能看到的是，我不明白你怎么能有这种方法的实际历史制度。

有一件事它确实提供了我的做法是，所有页面的选择是相当集中。我会用某种枚举或至少与字符串值静态类，以防止自己mongling了联系。

在任何情况下，我认为这一点可以为这个来概括： ~~你的用户点击~~您的用户（一个或多个）执行动作交换基于一些中央页面元素的含量。

Answer 2:

我会用超链接和历史课。关于超链接类的好处是，它设置这个标记（例如＃foobar的），以及所有你所要做的，就是抓住事件中，当令牌的值被改变（ValueChangeEvent）被解雇。在事件处理程序，你会然后替换页。

例如：欢迎页面的地址：此页面上www.yourpage.com/#home将“浏览书” -page一个链接，点击该链接时，新的地址将是这样的：www.yourpage.com /＃浏览

这里是代码：

 public class MainEntryPoint implements EntryPoint, ValueChangeHandler { VerticalPanel panel = new VerticalPanel(); Label label=new Label(); public void onModuleLoad() { Hyperlink link1 = new Hyperlink("books", "browse"); Hyperlink link2 = new Hyperlink("user details", "details"); panel.add(link1); panel.add(link2); panel.add(label); RootPanel.get().add(panel); History.addValueChangeHandler(this); //when there is no token, the "home" token is set else changePage() is called. //this is useful if a user has bookmarked a site other than the homepage. if(History.getToken().isEmpty()){ History.newItem("home"); } else { changePage(History.getToken()); } } 
  public void onValueChange(ValueChangeEvent event) { changePage(History.getToken()); } public void changePage(String token) { if(History.getToken().equals("browse")) { label.setText("Here would be some books"); } else if (History.getToken().equals("details")) { label.setText("Here would be the user details"); } else { label.setText("Welcome page"); } } 
   }

Answer 3:

真棒！我结合克里斯R.与克里斯Boesing的答案拿出这样的：

这是“索引”开始页面

public class Index implements EntryPoint, ValueChangeHandler<String> {
    public void onModuleLoad() {
        History.addValueChangeHandler(this);
        if (History.getToken().isEmpty()) History.newItem("index");
        Composite c = new Login(); 
        FlowControl.go(c);
    }

    public void onValueChange(ValueChangeEvent<String> e) {
        FlowControl.go(History.getToken());
    }
}

这是根据克里斯R.控制器，或ContentContainer

public class FlowControl {
private static FlowControl instance;
private FlowControl() {}
public static void go(Composite c) {
    if (instance == null) instance = new FlowControl(); // not sure why we need this yet since everything is static.
    RootPanel.get("application").clear();
    RootPanel.get("application").getElement().getStyle().setPosition(Position.RELATIVE); // not sure why, but GWT throws an exception without this. Adding to CSS doesn't work.
    // add, determine height/width, center, then move. height/width are unknown until added to document. Catch-22!
    RootPanel.get("application").add(c);
    int left = Window.getClientWidth() / 2 - c.getOffsetWidth() / 2; // find center
    int top = Window.getClientHeight() / 2 - c.getOffsetHeight() / 2;
    RootPanel.get("application").setWidgetPosition(c, left, top);
    History.newItem(c.getTitle()); // TODO: need to change and implement (or override) this method on each screen
}

public static void go(String token) {
    if (token == null) go(new Login());
    if (token.equals("cart")) go(new Cart());
    if (token.equals("login")) go(new Login());
    // Can probably make these constants in this class
}

然后你可以辣椒超链接和按钮在你的代码的任何地方。（有没有试过超链接呢。）

    Button submit = new Button("Submit");
    submit.addClickHandler(new ClickHandler() {
        public void onClick(ClickEvent event) {
            FlowControl.go(new MyScreen());             
        }           
    });

我添加一个div到我的HTML

<!-- This is where the application will reside within. It is controlled by FlowControl class. -->
<div id="application"></div>

现在，所有屏幕必须在构造函数，而不是向RootPanel调用initWidget（），因为它是一个综合类的现在，像

    initWidget(myPanel); // all composites must call this in constructor

Answer 4:

如果你希望它是FULL Ajax化（像一个桌面应用程序），当然你只需要一个页面。然后，只需改变取决于链路上的正文的内容。

此外，还有一个谷歌组GWT，这是非常非常活跃，我知道这之前已经有问，你只需要使用“搜索”功能。

Answer 5:

GWT多页 -多页GWT应用简单的框架。

Answer 6:

您可以使用MVP百通。这里是MI简单的库https://code.google.com/p/gwt-simple-mvp/wiki/GettingStarted 。

你可以拆分代码更js文件。 https://code.google.com/p/gwt-spliting/

Answer 7:

我用克洛伊S.答案（合并克里斯R.与克里斯Boesing的答案）来构建这个程序控制器工作GWT Web应用程序。在生产版本测试（和工作100％），但低于这个删节版本将需要进行修改，以与自己的应用程序整合（通过重命名翻页键的菜单项开始）。

AppController.java ：

/**
 * This App Controller utilizes two static inner-classes (Pages and External) 
 * to manage and server multiple pages with multiple sub-page (through their presenters) 
 * via String key constants which also serve as the literal text for the menu items.
 * 
 * Pages are added as menu commands in their respective views:
 *  // Add menu items to the menu with commands:
 *  menuItems.put(Pages.PAGE1, mainMenu.addItem(Pages.PAGE1, new Command() {
 *      public void execute() {
 *          History.newItem(Pages.PAGE1);
 *      }
 *  }));
 * 
 * Pages are fired as History tokens (from entry point java class):
 * 
 *   **
 *   * Receives history events and pushes them to the AppController using a deferred command.
 *   * Changes the cursor to show waiting.
 *   * @param the value change token
 *   *
 *  public void onValueChange(ValueChangeEvent<String> e) {
 *      // check token to cover first historical "back" navigation:
 *      if(!History.getToken().isEmpty()) {
 *          AppController.waitCursor.execute(); // cursor is reset in page attach method
 *      }
 *      Scheduler.get().scheduleDeferred(new ScheduledCommand() {
 *          public void execute() {
 *              AppController.go(History.getToken());
 *          }
 *      });
 *  }
 *  
 * Wait cursors are implemented as CSS:
 *
 *  body.wait, body.wait * {
 *      cursor: wait !important;   
 *  }
 * 
 * NOTE: This page swapping implementation technique (based on the StackOverflow solution 
 * found here: [http://stackoverflow.com/questions/1061705/multiple-pages-tutorial-in-google-web-toolkit-gwt][1]) 
 * differs from the obtuse and ancient 2010 GWT framework documentation in that the App Controller manages / handles 
 * adding the widget to the container, and therefore all the Presenters must implement the 
 * "AppControlPresenter" or "AppControlContainerPresenter" interface to give it access to their containers.
 * (thus eliminating "public void go(final HasWidgets container);" method in all presenter architecture except for 'MainAppPresenter')
 * There is also no event bus; static method calls are used for any needed interactivity.
 *
 * Includes a popup for pages still under construction.
 */

package com.;

import com.google.gwt.core.client.GWT;
import com.google.gwt.core.client.Scheduler;
import com.google.gwt.core.client.Scheduler.ScheduledCommand;
import java.util.HashMap;
import java.util.Map;
import com.google.gwt.dom.client.Style.Unit;
import com.google.gwt.event.logical.shared.AttachEvent;
import com.google.gwt.event.logical.shared.ResizeEvent;
import com.google.gwt.event.shared.HandlerManager;
import com.google.gwt.user.client.History;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.DecoratedPopupPanel;
import com.google.gwt.user.client.ui.Frame;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.Image;
import com.google.gwt.user.client.ui.LayoutPanel;
import com.google.gwt.user.client.ui.RootLayoutPanel;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.UIObject;

/**
 * 
 */
public class AppController {
    /** */
    public final static String DEFAULT_INITIAL_PAGE1_SUB_PAGE = Pages.PAGE_1A;
    /** Singleton instance for the AppController */
    private static AppController instance = new AppController();
    /** Presenter for the main app */
    private static MainAppPresenter mainAppPresenter;
    /** container for the different views */
    private static LayoutPanel container;
    /** sub-container for the different sub-views */
    private static LayoutPanel page1Container;
    /** */
    private static DecoratedPopupPanel popup;
    /** constant for Style-Dependent names for menu items (see menu-style.css) */
    public final static String MENU_ACTIVE_STYLE = "active";
    /** constant for Style-Dependent class name in css */
    public final static String CURSOR_WAIT_CLASS = "wait";  
    /** */
    public final static String POPUP_DEMO_ID = "popupDemo";
    /** */  
    public final static int DEMOP_POPUP_VERTICAL_OFFSET = 0;
    /** */
    public final static String POPUP_DEMO_STATEMENT = "<span class='text'>This page is under construction</span>"
                                                    + "<span class='char'>&hellip;</span>";
    /** */
    public static ScheduledCommand waitCursor = new ScheduledCommand() {
        @Override
        public void execute() { 
            AppController.waitCursor(true); 
        }
    };

    /** */
    public static ScheduledCommand normalCursor = new ScheduledCommand() {
        @Override
        public void execute() { 
            AppController.waitCursor(false); 
        }
    };

    /** Flag for determining if the page was reloaded */
    private static boolean reloaded = false;

    private static final LoginServiceAsync loginRpcService = GWT.create(LoginService.class);

    /**
     * Called on the resize event to set the position of the demo popup
     * window to be adjusted to the correct dimensions (size and positoin)
     * regardless of screen size.
     */
    private static ScheduledCommand resetPopupDimensions = new ScheduledCommand() {
        @Override
        public void execute() {
            if(!UNDER_CONSTRUCTION || popup == null) {
                return;
            }
            int demoWidth = Math.round(Window.getClientWidth() / MainApp.PHI),
                demoYPosition = Window.getClientHeight() / 2 - Math.round(popup.getOffsetHeight() / 2);
            popup.setWidth(String.valueOf(demoWidth) + "px");
            if(popup.getOffsetWidth() >= Window.getClientWidth()) {
                popup.setWidth("100%");
                popup.setPopupPosition(0, demoYPosition);
            } else {
                popup.setPopupPosition(Window.getClientWidth() / 2 - (popup.getOffsetWidth() / 2), demoYPosition);
            }
        }
    };

    /** */
    private static final String LOGIN_OBJECT_NAME = "Login Presenter Object";

    /**
     * static inner-class for external websites 
     */
    public static class External {
        /** The frame to contain the website */
        private static Frame frame;
        /**  */
        public static final String EXTERNAL_URL_1 = "http://";
        /**  */
        public static final String EXTERNAL_URL_2 = "http://";

        /**
         * @returns true if the name of the token is equal to one of the URLs
         * @param token the name to check
         */
        public static boolean has(String token) {
            return token.equalsIgnoreCase(EXTERNAL_URL_1)      ||
                   token.equalsIgnoreCase(EXTERNAL_URL_2);
        }

        /**
         * Gets the external Frame object
         * @param url
         * @return Frame
         */
        public static Frame get(String url) {
            if(frame == null) {
                frame = new Frame(url);
                frame.addAttachHandler(new AttachEvent.Handler() {
                    @Override
                    public void onAttachOrDetach(AttachEvent event) { 
                        // hide the popup:
                        showPopup(false);
                        Scheduler.get().scheduleFinally(resetPopupDimensions);
                        Scheduler.get().scheduleFinally(normalCursor);
                    }
                });
            }
            else if(!frame.getUrl().equalsIgnoreCase(url)) {
                frame.setUrl(url);
            }
            return frame;
        }
    }

    /**
     * static inner-class for holding pages activated by the app's main menu commands
     */
    public static class Pages {
        /** */
        public static final String PAGE1 = "foo";
        /** */
        public static final String PAGE2 = "bar";
        /** */
        public static final String PAGE_1A = "baz";
        /** */
        public static final String PAGE_1B = "qux";
        /** */
        public static String lastPage;
        /** */
        public static String lastPage1SubPage;
        /** */
        public static String unsavedMessage;
        /** */
        private static HashMap<String, AppControlPresenter> pageMap;
        /** */
        private static AppControlPresenter presenter;
        /** */
        private static Composite view;

        /**
         * initializes the hashmap of pages  
         */
        public static void init() {
            pageMap = new HashMap<String, AppControlPresenter>();
        }

        /**
         * @returns true if the name of the token is equal to one of the pages
         * @param token the name to check
         */
        public static boolean has(String token) {
            return token.equalsIgnoreCase(PAGE1)            ||
                   token.equalsIgnoreCase(PAGE2)            ||
                   token.equalsIgnoreCase(PAGE_1A);
        }


        /**
         * Gets the correct page container to display as a Composite
         * @param page the token name of the page
         * @return Composite page
         */
        public static Composite get(String page) {
            view = null;
            presenter = null;
            if(page.equalsIgnoreCase(PAGE1)) {
                if(pageMap.get(PAGE1) == null) {
                    pageMap.put(PAGE1, new Page1Presenter(PAGE1)); 
                    page1Container = ((AppControlContainerPresenter) pageMap.get(PAGE1)).getContentPane();
                }
                presenter = pageMap.get(PAGE1);
                lastPage = page;
                mainAppPresenter.setCurrentMenuItem(page);
            }
            else if(page.equalsIgnoreCase(PAGE_1A) ||
                    page.equalsIgnoreCase(PAGE_1B) {
                if(pageMap.get(PAGE1) == null) {
                    pageMap.put(PAGE1, new Page1Presenter(PAGE1)); 
                    page1Container = ((AppControlContainerPresenter) pageMap.get(PAGE1)).getContentPane();
                }
                presenter = pageMap.get(PAGE1);
                lastPage1SubPage = page;
                view = ((AppControlContainerPresenter)presenter).setCurrentPage(page);
            }
            else if(page.equalsIgnoreCase(PAGE2)) {
                if(pageMap.get(PAGE2) == null) {
                    pageMap.put(PAGE2, new Page2Presenter(PAGE2));
                }
                presenter = pageMap.get(PAGE2);
                lastPage = PAGE2;
                mainAppPresenter.setCurrentMenuItem(page);
            }
            else if(External.has(page)) {
                throw new Error("App Controller Error -- Use 'External' inner-class for: " + page);
            }
            else {
                throw new Error("App Controller Error -- Page name not found: " + page);
            }
            if(view == null) {
                view = (Composite)presenter.view();
            }
            view.addAttachHandler(new AttachEvent.Handler() {
                @Override
                public void onAttachOrDetach(AttachEvent event) {
                    AppController.showPopup(false);
                    presenter.updateAttachOrDetach(event);
                    Scheduler.get().scheduleFinally(resetPopupDimensions);
                    Scheduler.get().scheduleFinally(normalCursor);
                }
            });
            return view;
        }

        /**
         * Gets the current AppControlPresenter for the last page.
         * @returns the current AppControlPresenter  
         */
        public static AppControlPresenter getCurrentPresenter() {
            return presenter;
        }

        /**
         * Gets an AppControlPresenter from the pageMap.
         * @param token the name of the presenter
         * @returns the AppControlPresenter  
         */
        public static AppControlPresenter getPresenter(String token) {
            return pageMap.get(token);
        }

        /**
         * Returns true if the page is already loaded.
         * @param token name of the page
         */
        public static boolean alreadyLoaded(String token) {
            MainApp.debug(1, "[already loaded: " + presenter.toString() + " (token: " + token + ")");
            return presenter.toString().equalsIgnoreCase(token);
        }

        /**
         * Returns true if the page is visible
         * @param page the token name of the page
         */
        public static boolean isVisible(String page) {
            UIObject component = pageMap.get(page).view();
            return !(component.getOffsetHeight() == 0 && component.getOffsetWidth() == 0);
        }

        /**
         * Returns true if the page is visible
         * @param presenter the AppControlPresenter instance
         */
        public static boolean isVisible(AppControlPresenter presenter) {
            UIObject component = presenter.view();
            return !(component.getOffsetHeight() == 0 && component.getOffsetWidth() == 0);
        }

        /**
         * Returns true if the application has unsaved data.
         * Iterates through all the pages and checks each presenter.
         */
        public static boolean unsavedData() {
            if(pageMap.isEmpty()) return false;
            boolean unsaved = false;
            for(Map.Entry<String, AppControlPresenter> entry : pageMap.entrySet()) {
                AppControlPresenter presenter = entry.getValue();
                if(presenter != null && presenter.unsavedData()) {
                    MainApp.debug(1, "(!) " + presenter.toString() + " has unsaved data");
                    unsavedMessage = presenter.dataDescription();
                    unsaved = true;
                    break; // just need to know one exists for now (window closing event)
                }
            }
            return unsaved;
        }

        /**
         * Called on a resize event on the window. Iterates through all the pages
         * and tells their presenters to resize their content.
         */
        public static void resize() {
            for(Map.Entry<String, AppControlPresenter> entry : pageMap.entrySet()) {
                AppControlPresenter presenter = entry.getValue();
                if(presenter != null && isVisible(presenter)) {
                    presenter.resize();
                }
            }
        }
    } //end class Pages

    /**
     * @returns true if the history token is equal to any of the pages in the app 
     */
    public static boolean hasHistory() {
        String token = History.getToken();
        return External.has(token) || Pages.has(token);
    }

    /**
     * Starts the login view at the root layout level
     */
    public static void goLoginScreen() {
        //check for reload:
        if(hasHistory()) {
            MainApp.debug(1, "(!) AppController has History on Login");
            reloaded = true;
        }
        else {
            reloaded = false;
        }
        RootLayoutPanel.get().clear();
        RootLayoutPanel.get().add(new LoginPresenter(LOGIN_OBJECT_NAME).view());
    }

    /**
     * @returns the last "Page1" page
     */
    public static String getLastPage1Page() {
        if(Pages.lastPage1SubPage == null || Pages.lastPage1SubPage.isEmpty()) {
            Pages.lastPage1SubPage = DEFAULT_INITIAL_PAGE1_SUB_PAGE;
        }
        return Pages.lastPage1SubPage;
    }

    /**
     * Tells the app to start with the Page1 page.
     * @param username the username of the person logged-in
     */
    public static void goMainApp(String username) {
        //hide the login background:
        RootPanel.getBodyElement().getStyle().setProperty("background", "none");
        mainAppPresenter = new MainAppPresenter(username);
        RootLayoutPanel.get().clear();
        mainAppPresenter.go(RootLayoutPanel.get());
        //get the center panel:
        container = mainAppPresenter.getContainer();
        //check for reload:
        //NOTE: the token will be empty if the user refreshes 
        //      and navigates all the way back to the zero-state 
        //      from the login screen. 
        //NOTE: this logic may change after user-persistence is implemented
        if(hasHistory() || History.getToken().isEmpty()) {
            // reset the reloaded flag:
            reloaded = false;
            if(History.getToken().isEmpty()) {
                //land on the first page:
                History.newItem(AppController.Pages.PAGE1);
            }
            else {
                MainApp.debug(2, "(!) AppController has History on reload: " + History.getToken());
                History.fireCurrentHistoryState();
            }
        }
        else {
            //land on the first page:
            History.newItem(AppController.Pages.PAGE1);
        }

    }

    /**
     * 
     */
    public static void checkIfSessionActive() { 
        loginRpcService.loginFromSession(new AsyncCallback<LoginSummary>() {
            @Override
            public void onFailure(Throwable throwable) {
                goLoginScreen();
            }

            @Override
            public void onSuccess(LoginSummary loginSummary) {
                if (loginSummary.getErrorString() != null)
                    goLoginScreen();
                else
                    goMainApp(loginSummary.getUser().getName());
            }
        });
    }

    /**
     * 
     */
    public static void sessionLogout() {
        DialogBoxWidget.confirm(200,
                "Logout",
                "Are you sure you want to log out?",
                new ConfirmDialogCallback() {
                    @Override
                    public void onAffirmative() {

                        loginRpcService.logout(new AsyncCallback<Void>() {
                            @Override
                            public void onFailure(Throwable throwable) {
                                goLoginScreen();
                            }

                            @Override
                            public void onSuccess(Void aVoid) {
                                goLoginScreen();
                            }
                        });
                    }

                    @Override
                    public void onCancel() {
                    }
                });

    }

    /**
     * Shows or hides the "Under Construction" popup if UNDER_CONSTRUCION is true.
     * @param show true to show and false to hide
     */
    public static void showPopup(boolean show) {
        if(MainApp.UNDER_CONSTRUCTION && popup != null) {
            if(show) {
                popup.show();
            }
            else {
                popup.hide();
            }
        }
    }

    /**
     * Called by every history event fired (including the back and forward buttons).
     * Ignores the login and empty index historically.
     * @param token the name of the page to load
     */
    public static void go(String token) {
        if(reloaded) {
            normalCursor.execute();
        }
        if(token == null || token.isEmpty() || reloaded == true) return;
        MainApp.debug("<history changed> - AppController.go()-> " + token);
        // build the popup message for all unfinished pages:
        if(MainApp.UNDER_CONSTRUCTION) {
            if(popup == null) {
                popup = new DecoratedPopupPanel(false);
                popup.ensureDebugId(POPUP_DEMO_ID);
                popup.addStyleDependentName(POPUP_DEMO_ID);
                popup.setWidget(new HTML(new Image("images/workingman.png") + POPUP_DEMO_STATEMENT + new Image("images/workingmanFLIP.png")));
            }
        }
        // check token for which page to return:
        if(token.equalsIgnoreCase(External.EXTERNAL_URL_1)) {
            MainAppPresenter.clearActiveMenuItems();
            setExternalContentURL(External.get(token));
        }
        else if(token.equalsIgnoreCase(External.EXTERNAL_URL_2)) {
            MainAppPresenter.clearActiveMenuItems();
            setExternalContentURL(External.get(token));
        }
        else if(token.equalsIgnoreCase(Pages.PAGE1)) {
            setContent(Pages.get(Pages.PAGE1));
            setPage1Content(Pages.get(getLastPage1Page()));
        }
        else if(token.equalsIgnoreCase(Pages.PAGE_1A) ||
                token.equalsIgnoreCase(Pages.PAGE_1B)) {
            setContent(Pages.get(Pages.PAGE1));
            setPage1Content(Pages.get(token));
        }
        else if(token.equalsIgnoreCase(Pages.PAGE2)) {
            setContent(Pages.get(Pages.PAGE2));
        }
        else { // default behavior for a page not described:
            MainApp.debug(2, "(!) Unknown page: " + token);
            setContent(Pages.get(token));
        }
    }

    /**
     * Called by MainApp on a window resize event.
     * @param e the ResizeEvent
     */
    public static void resize(ResizeEvent e) {
        Scheduler.get().scheduleDeferred(new ScheduledCommand() {
            @Override
            public void execute() {
                if(mainAppPresenter != null) {
                    mainAppPresenter.resize();
                }
                Pages.resize();
                Scheduler.get().scheduleFinally(resetPopupDimensions);
            }
        });
    }

    /**
     * Changes the cursor to "wait" or "auto" depending on the parameter
     * @param wait true to set the cursor to waiting
     */
    private static void waitCursor(Boolean wait) {
        if(wait) {
            RootPanel.getBodyElement().addClassName(CURSOR_WAIT_CLASS);
        }
        else {
            RootPanel.getBodyElement().removeClassName(CURSOR_WAIT_CLASS);
        }
    }
    /**
     * Private Constructor which initializes the Pages object.
     */
    private AppController() {
        Pages.init();
    }

    /**
     * Sets the content of the main app container to one of the "Pages."
     * @param c the Composite widget to be added
     */
    private static void setContent(Composite c) {
        container.clear();
        container.add(c.asWidget());
    }

    /**
     * Sets the content of the main app container an external URL.
     * @param f the Frame by which external web sites are added
     */ 
    private static void setExternalContentURL(Frame f) {
        container.clear();
        container.add(f);
        // must reset the width and height every time:
        f.getElement().getStyle().setWidth(100, Unit.PCT);
        f.getElement().getStyle().setHeight(100, Unit.PCT);
    }

    /**
     * Sets the content of the Page1 container to one of the sub pages.
     * @param c the Composite widget to be added
     */
    private static void setPage1Content(Composite c) {
        page1Container.clear();
        page1Container.add(c.asWidget());
    }
}

AppControlPresenter.java:

package com.*;

import com.google.gwt.event.logical.shared.AttachEvent;
import com.google.gwt.user.client.ui.Composite;

/**
 * Base interface for all 'Presenters' used by AppController.java
 * NOTE: classes that implement this interface do not launch the presenter's view 
 * into the provided container; rather, the view is retrieved and used by the 
 * AppController instance by calling the 'view()' method
 */
public interface AppControlPresenter {

    /**
     * Gets the view (for use in AppController.java)
     */
    public Composite view();

    /**
     * Indicates if current search data is present and unsaved.
     * @returns true to if a search is still active  
     */
    public boolean unsavedData();

    /**
     * Called on resize event to notify presenters with visible
     * components that need resizing for different screen sizes.
     * @returns true if elements were resized
     */
    public boolean resize();

    /**
     * Called on attachEvents to tell the presenter to update.
     * @param event the AttachEvent
     */
    public void updateAttachOrDetach(AttachEvent event);

    /**
     * Gets the message to display for unsaved data.
     * @returns a message String describing the data
     */
    public String dataDescription();

    /**
     *  Gets a fully qualified name for use in comparisons
     * @return the name of this presenter used by the <code>AppController</code>
     */
    public String toString();
}

AppControlContainerPresenter.java:

package com.*;

import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.LayoutPanel;

/**
 */
public interface AppControlContainerPresenter extends AppControlPresenter {

    /**
     * 
     * @return
     */
    public LayoutPanel getContentPane();

    /**
     * 
     * @param pageName
     * @return
     */
    public Composite setCurrentPage(String pageName);
}