1

该应用程序尝试在主显示页面上显示其 3 个视图，如下所示：

  1. “页面顶部”的 AAAView
  2. “页面中间”的 BBBView
  3. “页面底部”的 CCCView

问题： 虽然应用程序运行，但它不会如上所述定位视图（即“AAAView”、“BBBView”、“CCCView”）。

（比如“AAAView”显示在“页面底部”，“BBBView”和“CCCView”显示在“页面中间”...--这是为什么？）

我认为问题是由于我误用（误解？）ActivityMapper/ActivityManager 类在主页上正确放置（或定位）视图/面板造成的。

不幸的是，我无法找到任何关于如何正确/有效地使用 ActivityMapper/ActivityManager 类的综合文档。（到目前为止，我看到的示例应用程序通常过于复杂，以至于我无法准确隔离 ActivityMapper/ActivityManager 类如何工作以指定面板/视图在主页上的显示位置）

应用程序中使用的代码如下所示...

（对我做错的任何建议或解释将不胜感激......——而且，我想我不是唯一一个在这个概念上苦苦挣扎的人）

感谢您的任何帮助！！

/src/aaa/bbb/ccc/app.gwt.xml

<?xml version="1.0" encoding="UTF-8"?>
<module rename-to='app'>
    <inherits name='com.google.gwt.user.User' />
    <inherits name='com.google.gwt.user.theme.standard.Standard' />
    <inherits name="com.google.gwt.activity.Activity" />
    <inherits name="com.google.gwt.place.Place" />
    <entry-point class='aaa.bbb.ccc.client.AppEntryPoint' />
    <source path='client' />
    <source path='shared' />
</module>

/src/aaa/bbb/ccc/client/AppEntryPoint

package aaa.bbb.ccc.client;

import com.google.gwt.activity.shared.ActivityManager;

public class AppEntryPoint extends LayoutPanel implements EntryPoint
{

    private LayoutPanel mainView = null;

    interface AppEntryPointUiBinder extends UiBinder<LayoutPanel, AppEntryPoint>
    {
    }

    private static AppEntryPointUiBinder uiBinder = GWT.create(AppEntryPointUiBinder.class);

    @UiField
    SimplePanel topOfPage;

    @UiField
    SimplePanel middleOfPage;

    @UiField
    SimplePanel bottomOfPage;

    public AppEntryPoint()
    {
        super();
    }

    AcceptsOneWidget top = new AcceptsOneWidget()
    {
        public void setWidget(IsWidget activityWidget)
        {
            Widget widget = Widget.asWidgetOrNull(activityWidget);
            mainView.setWidgetVisible(topOfPage, widget != null);
            topOfPage.setWidget(widget);
        }
    };

    AcceptsOneWidget mid = new AcceptsOneWidget()
    {
        public void setWidget(IsWidget activityWidget)
        {
            Widget widget = Widget.asWidgetOrNull(activityWidget);
            mainView.setWidgetVisible(middleOfPage, widget != null);
            middleOfPage.setWidget(widget);
        }
    };    

    AcceptsOneWidget bot = new AcceptsOneWidget()
    {
        public void setWidget(IsWidget activityWidget)
        {
            Widget widget = Widget.asWidgetOrNull(activityWidget);
            mainView.setWidgetVisible(bottomOfPage, widget != null);
            bottomOfPage.setWidget(widget);
        }
    };

    public void onModuleLoad()
    {
        ClientFactory clientFactory = GWT.create(ClientFactory.class);
        mainView = uiBinder.createAndBindUi(this);
        EventBus eventBus = clientFactory.getEventBus();

        ActivityMapper aaaActivityMapper = new AAAActivityMapper(clientFactory);
        ActivityManager aaaActivityManager = new ActivityManager(aaaActivityMapper, eventBus);
        aaaActivityManager.setDisplay(top);

        ActivityMapper bbbActivityMapper = new BBBActivityMapper(clientFactory);
        ActivityManager bbbActivityManager = new ActivityManager(bbbActivityMapper, eventBus);
        bbbActivityManager.setDisplay(mid);

        ActivityMapper cccActivityMapper = new CCCActivityMapper(clientFactory);
        ActivityManager cccActivityManager = new ActivityManager(cccActivityMapper, eventBus);
        cccActivityManager.setDisplay(bot);

        AppPlaceHistoryMapper historyMapper = GWT.create(AppPlaceHistoryMapper.class);

        PlaceController placeController = clientFactory.getPlaceController();
        PlaceHistoryHandler historyHandler = new PlaceHistoryHandler(historyMapper);
        historyHandler.register(placeController, eventBus, new AAAPlace());

        RootLayoutPanel.get().add(mainView);
        historyHandler.handleCurrentHistory();
    }
}

/src/aaa/bbb/ccc/client/AppEntryPoint.ui.xml

<!DOCTYPE ui:UiBinder SYSTEM "http://dl.google.com/gwt/DTD/xhtml.ent">
<ui:UiBinder xmlns:ui='urn:ui:com.google.gwt.uibinder'
    xmlns:g='urn:import:com.google.gwt.user.client.ui' xmlns:h='urn:import:aaa.bbb.ccc.client'>
    <ui:style src="app.css" />
    <g:LayoutPanel width="800" height='600'>
        <g:layer left='10%' right='10%' top='4px' height='10em'>
            <g:SimplePanel ui:field="topOfPage"/>
        </g:layer>
        <g:layer left='10%' right='10%' top='204px' height='10em'>
            <g:SimplePanel ui:field="middleOfPage"/>
        </g:layer>
        <g:layer left='10%' right='10%' top='404px' height='10em'>
            <g:SimplePanel ui:field="bottomOfPage"/>
        </g:layer>
    </g:LayoutPanel>
</ui:UiBinder>

/src/aaa/bbb/ccc/client/ClientFactory.java

package aaa.bbb.ccc.client;

import com.google.gwt.event.shared.EventBus;
import com.google.gwt.event.shared.SimpleEventBus;
import com.google.gwt.place.shared.PlaceController;

public class ClientFactory
{
    public ClientFactory()
    {
    }

    private static final EventBus eventBus = new SimpleEventBus();
    private static final PlaceController placeController = new PlaceController(eventBus);
    private static final AAAView aaaView = new AAAView();
    private static final BBBView bbbView = new BBBView();
    private static final CCCView cccView = new CCCView();

    public EventBus getEventBus()
    {
        return eventBus;
    }

    public PlaceController getPlaceController()
    {
        return placeController;
    }

    public AAAView getAAAView()
    {
        return aaaView;
    }

    public BBBView getBBBView()
    {
        return bbbView;
    }

    public CCCView getCCCView()
    {
        return cccView;
    }
}

/src/aaa/bbb/ccc/client/AppPlaceHistoryMapper.java

package aaa.bbb.ccc.client;

import com.google.gwt.place.shared.PlaceHistoryMapper;
import com.google.gwt.place.shared.WithTokenizers;

@WithTokenizers({AAAPlace.Tokenizer.class, BBBPlace.Tokenizer.class })
public interface AppPlaceHistoryMapper extends PlaceHistoryMapper
{
}

/src/aaa/bbb/ccc/client/AAAView.java

package aaa.bbb.ccc.client;

import com.google.gwt.core.client.GWT;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.uibinder.client.UiBinder;
import com.google.gwt.uibinder.client.UiField;
import com.google.gwt.uibinder.client.UiHandler;
import com.google.gwt.user.client.ui.AcceptsOneWidget;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.HTMLPanel;
import com.google.gwt.user.client.ui.IsWidget;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.SimplePanel;
import com.google.gwt.user.client.ui.Widget;

public class AAAView extends SimplePanel implements IsWidget, AcceptsOneWidget
{
    private final HTMLPanel aaaView;
    private Presenter presenter;

    private static AAAViewUiBinder uiBinder = GWT.create(AAAViewUiBinder.class);   
    interface AAAViewUiBinder extends UiBinder<HTMLPanel, AAAView>
    {
    }

    public AAAView()
    {
        aaaView = uiBinder.createAndBindUi(this);
    }

    @UiField
    Label aaaViewLabel;

    @UiField
    Button bbbButton;

    @UiHandler("bbbButton")
    void onBBBButtonClicked(ClickEvent event)
    {
        presenter.gotoBBBPlace();
    }

    @UiField
    Button cccButton;

    @UiHandler("cccButton")
    void onCCCButtonClicked(ClickEvent event)
    {
        presenter.gotoCCCPlace();
    }

    public void setName(String name)
    {
        aaaViewLabel.setText(name);
    }

    public void setPresenter(Presenter presenter)
    {
        this.presenter = presenter;
    }    
    public interface Presenter
    {
        void gotoBBBPlace();
        void gotoCCCPlace();
    }

    @Override
    public Widget asWidget()
    {
        return aaaView;
    }
}

/src/aaa/bbb/ccc/client/AAAView.ui.xml

<!DOCTYPE ui:UiBinder SYSTEM "http://dl.google.com/gwt/DTD/xhtml.ent">
<ui:UiBinder xmlns:ui="urn:ui:com.google.gwt.uibinder"
    xmlns:g="urn:import:com.google.gwt.user.client.ui">
    <ui:style src="app.css" />
    <g:HTMLPanel  ui:field="aaaView" styleName='{style.aaaView}'>
        <g:Label  ui:field="aaaViewLabel" text="AAAView" styleName='{style.viewLabel}'></g:Label>
        <g:Button ui:field="bbbButton" text="go to bbbView"></g:Button>
        <g:Button ui:field="cccButton" text="go to cccView"></g:Button>
    </g:HTMLPanel>
</ui:UiBinder>

/src/aaa/bbb/ccc/client/AAAActivity.java

package aaa.bbb.ccc.client;

import com.google.gwt.activity.shared.AbstractActivity;
import com.google.gwt.event.shared.EventBus;
import com.google.gwt.place.shared.PlaceController;
import com.google.gwt.user.client.ui.AcceptsOneWidget;

public class AAAActivity extends AbstractActivity implements AAAView.Presenter
{
    private String name = "...the AAAView...";    
    private final AAAView aaaView;
    private final PlaceController placeController;

    public AAAActivity(ClientFactory clientFactory)
    {
        aaaView = clientFactory.getAAAView();
        placeController = clientFactory.getPlaceController();
    }

    @Override
    public void start(AcceptsOneWidget panel, EventBus eventBus)
    {
        aaaView.setPresenter(this);
        aaaView.setName(name);
        panel.setWidget(aaaView.asWidget());
    }    

    @Override
    public void gotoBBBPlace()
    {
        placeController.goTo(new BBBPlace());
    }

    @Override
    public void gotoCCCPlace()
    {
        placeController.goTo(new CCCPlace());
    }    
}

/src/aaa/bbb/ccc/client/AAAActivityMapper.java

package aaa.bbb.ccc.client;

import com.google.gwt.activity.shared.Activity;
import com.google.gwt.activity.shared.ActivityMapper;
import com.google.gwt.place.shared.Place;

public class AAAActivityMapper implements ActivityMapper
{
    private ClientFactory clientFactory;

    public AAAActivityMapper(ClientFactory clientFactory)
    {
        this.clientFactory = clientFactory;
    }

    @Override
    public Activity getActivity(Place place)
    {

        if (place instanceof BBBPlace)
        {
            return new BBBActivity(clientFactory);//return bbbActivityMapper.getActivity(place);
        }
        else
        if (place instanceof CCCPlace)
        {
            return new CCCActivity(clientFactory);//return cccActivityMapper.getActivity(place);
        }

        return null;
    }
}

/src/aaa/bbb/ccc/client/AAAPlace.java

package aaa.bbb.ccc.client;

import com.google.gwt.place.shared.Place;
import com.google.gwt.place.shared.PlaceTokenizer;
import com.google.gwt.place.shared.Prefix;

public class AAAPlace extends Place
{
    private String aaaName = "AAAPlace";

    public AAAPlace()
    {
    }

    public String getAAAName()
    {
        return aaaName;
    }

    @Prefix("AAAPlace")
    public static class Tokenizer implements PlaceTokenizer<AAAPlace>
    {
        @Override
        public String getToken(AAAPlace place)
        {
            return place.getAAAName(); //"AAAName"; //place.getAAAName();
        }

        @Override
        public AAAPlace getPlace(String token)
        {
            return new AAAPlace();
        }
    }
}

/src/aaa/bbb/ccc/client/BBBView.java

package aaa.bbb.ccc.client;

import com.google.gwt.core.client.GWT;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.uibinder.client.UiBinder;
import com.google.gwt.uibinder.client.UiField;
import com.google.gwt.uibinder.client.UiHandler;
import com.google.gwt.user.client.ui.AcceptsOneWidget;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.HTMLPanel;
import com.google.gwt.user.client.ui.IsWidget;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.SimplePanel;
import com.google.gwt.user.client.ui.Widget;

public class BBBView extends SimplePanel implements IsWidget, AcceptsOneWidget
{
    private final HTMLPanel bbbView;
    private Presenter presenter;

    private static BBBViewUiBinder uiBinder = GWT.create(BBBViewUiBinder.class);    
    interface BBBViewUiBinder extends UiBinder<HTMLPanel, BBBView>
    {
    }

    public BBBView()
    {
        bbbView = uiBinder.createAndBindUi(this);
    }

    @UiField
    Label bbbViewLabel;

    @UiField
    Button aaaButton; 

    @UiHandler("aaaButton")
    void onAAAButtonClicked(ClickEvent event)
    {
        presenter.gotoAAAPlace();
    }

    @UiField
    Button cccButton; 

    @UiHandler("cccButton")
    void onCCCButtonClicked(ClickEvent event)
    {
        presenter.gotoCCCPlace();
    }

    public void setName(String name)
    {
        bbbViewLabel.setText(name);
    }

    public void setPresenter(Presenter presenter)
    {
        this.presenter = presenter;
    }    
    public interface Presenter
    {
        void gotoAAAPlace();
        void gotoCCCPlace();
    }

    @Override
    public Widget asWidget()
    {
        return bbbView;
    }
}

/src/aaa/bbb/ccc/client/BBBView.ui.xml

<!DOCTYPE ui:UiBinder SYSTEM "http://dl.google.com/gwt/DTD/xhtml.ent">
<ui:UiBinder xmlns:ui="urn:ui:com.google.gwt.uibinder"
    xmlns:g="urn:import:com.google.gwt.user.client.ui">
    <ui:style src="app.css" />
    <g:HTMLPanel  ui:field="bbbView" styleName='{style.bbbView}'>
        <g:Label  ui:field="bbbViewLabel" text="BBBView" styleName='{style.viewLabel}'></g:Label>
        <g:Button ui:field="aaaButton" text="go to aaaView"></g:Button>
        <g:Button ui:field="cccButton" text="go to cccView"></g:Button>
    </g:HTMLPanel>
</ui:UiBinder>

/src/aaa/bbb/ccc/client/BBBActivity.java

package aaa.bbb.ccc.client;

import com.google.gwt.activity.shared.AbstractActivity;
import com.google.gwt.event.shared.EventBus;
import com.google.gwt.place.shared.PlaceController;
import com.google.gwt.user.client.ui.AcceptsOneWidget;

public class BBBActivity extends AbstractActivity implements BBBView.Presenter
{
    private String name = "...the BBBView...";    
    private final BBBView bbbView;
    private final PlaceController placeController;

    public BBBActivity(ClientFactory clientFactory)
    {
        bbbView = clientFactory.getBBBView();
        placeController = clientFactory.getPlaceController();
    }

    @Override
    public void start(AcceptsOneWidget panel, EventBus eventBus)
    {
        bbbView.setPresenter(this);
        bbbView.setName(name);
        panel.setWidget(bbbView.asWidget());
    }    

    @Override
    public void gotoAAAPlace()
    {
        placeController.goTo(new AAAPlace());
    }

    @Override
    public void gotoCCCPlace()
    {
        placeController.goTo(new CCCPlace());
    }
}

/src/aaa/bbb/ccc/client/BBBActivityMapper.java

package aaa.bbb.ccc.client;

import com.google.gwt.activity.shared.Activity;
import com.google.gwt.activity.shared.ActivityMapper;
import com.google.gwt.place.shared.Place;

public class BBBActivityMapper implements ActivityMapper
{
    private ClientFactory clientFactory;

    public BBBActivityMapper(ClientFactory clientFactory)
    {
        this.clientFactory = clientFactory;
    }

    @Override
    public Activity getActivity(Place place)
    {
        if (place instanceof AAAPlace)
        {
            return new AAAActivity(clientFactory);//aaaActivityMapper.getActivity(place);
        }
        else
        if (place instanceof CCCPlace)
        {
            return new CCCActivity(clientFactory);//return cccActivityMapper.getActivity(place);
        }

        return null;
    }
}

/src/aaa/bbb/ccc/client/BBBPlace.java

package aaa.bbb.ccc.client;

import com.google.gwt.place.shared.Place;
import com.google.gwt.place.shared.PlaceTokenizer;
import com.google.gwt.place.shared.Prefix;

public class BBBPlace extends Place
{
    private String bbbName = "BBBPlace";

    public BBBPlace()
    {
    }

    public String getBBBName()
    {
        return bbbName;
    }

    @Prefix("BBBPlace")
    public static class Tokenizer implements PlaceTokenizer<BBBPlace>
    {
        @Override
        public String getToken(BBBPlace place)
        {
            return place.getBBBName(); //"BBBName"; //place.getBBBName();
        }

        @Override
        public BBBPlace getPlace(String token)
        {
            return new BBBPlace();
        }
    }
}

/src/aaa/bbb/ccc/client/CCCView.java

package aaa.bbb.ccc.client;

import com.google.gwt.core.client.GWT;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.uibinder.client.UiBinder;
import com.google.gwt.uibinder.client.UiField;
import com.google.gwt.uibinder.client.UiHandler;
import com.google.gwt.user.client.ui.AcceptsOneWidget;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.HTMLPanel;
import com.google.gwt.user.client.ui.IsWidget;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.SimplePanel;
import com.google.gwt.user.client.ui.Widget;

public class CCCView extends SimplePanel implements IsWidget, AcceptsOneWidget
{
    private final HTMLPanel cccView;
    private Presenter presenter;

    private static CCCViewUiBinder uiBinder = GWT.create(CCCViewUiBinder.class);   
    interface CCCViewUiBinder extends UiBinder<HTMLPanel, CCCView>
    {
    }

    public CCCView()
    {
        cccView = uiBinder.createAndBindUi(this);
    }

    @UiField
    Label cccViewLabel;

    @UiField
    Button aaaButton;

    @UiHandler("aaaButton")
    void onAAAButtonClicked(ClickEvent event)
    {
        presenter.gotoAAAPlace();
    }

    @UiField
    Button bbbButton;

    @UiHandler("bbbButton")
    void onBBBButtonClicked(ClickEvent event)
    {
        presenter.gotoBBBPlace();
    }

    public void setName(String name)
    {
        cccViewLabel.setText(name);
    }

    public void setPresenter(Presenter presenter)
    {
        this.presenter = presenter;
    }    
    public interface Presenter
    {
        void gotoAAAPlace();
        void gotoBBBPlace();
    }

    @Override
    public Widget asWidget()
    {
        return cccView;
    }
}

/src/aaa/bbb/ccc/client/BBBView.ui.xml

<!DOCTYPE ui:UiBinder SYSTEM "http://dl.google.com/gwt/DTD/xhtml.ent">
<ui:UiBinder xmlns:ui="urn:ui:com.google.gwt.uibinder"
    xmlns:g="urn:import:com.google.gwt.user.client.ui">
    <ui:style src="app.css" />
    <g:HTMLPanel  ui:field="cccView" styleName='{style.cccView}'>
        <g:Label  ui:field="cccViewLabel" text="CCCView" styleName='{style.viewLabel}'></g:Label>
        <g:Button ui:field="aaaButton" text="go to aaaView"></g:Button>
        <g:Button ui:field="bbbButton" text="go to bbbView"></g:Button>
    </g:HTMLPanel>
</ui:UiBinder>

/src/aaa/bbb/ccc/client/CCCActivity.java

package aaa.bbb.ccc.client;

import com.google.gwt.activity.shared.AbstractActivity;
import com.google.gwt.event.shared.EventBus;
import com.google.gwt.place.shared.PlaceController;
import com.google.gwt.user.client.ui.AcceptsOneWidget;

public class CCCActivity extends AbstractActivity implements CCCView.Presenter
{
    private String name = "...the CCCView...";    
    private final CCCView cccView;
    private final PlaceController placeController;

    public CCCActivity(ClientFactory clientFactory)
    {
        cccView = clientFactory.getCCCView();
        placeController = clientFactory.getPlaceController();
    }

    @Override
    public void start(AcceptsOneWidget panel, EventBus eventBus)
    {
        cccView.setPresenter(this);
        cccView.setName(name);
        panel.setWidget(cccView.asWidget());
    }    

    @Override
    public void gotoAAAPlace()
    {
        placeController.goTo(new AAAPlace());
    }

    @Override
    public void gotoBBBPlace()
    {
        placeController.goTo(new BBBPlace());
    }    
}

/src/aaa/bbb/ccc/client/CCCActivityMapper.java

package aaa.bbb.ccc.client;

import com.google.gwt.activity.shared.Activity;
import com.google.gwt.activity.shared.ActivityMapper;
import com.google.gwt.place.shared.Place;

public class CCCActivityMapper implements ActivityMapper
{
    private ClientFactory clientFactory;

    public CCCActivityMapper(ClientFactory clientFactory)
    {
        this.clientFactory = clientFactory;
    }

    @Override
    public Activity getActivity(Place place)
    {
        if (place instanceof AAAPlace)
        {
            return new AAAActivity(clientFactory);//return aaaActivityMapper.getActivity(place);
        }
        else
        if (place instanceof BBBPlace)
        {
            return new BBBActivity(clientFactory);//return aaaActivityMapper.getActivity(place);
        }

        return null;
    }
}

/src/aaa/bbb/ccc/client/CCCPlace.java

package aaa.bbb.ccc.client;

import com.google.gwt.place.shared.Place;
import com.google.gwt.place.shared.PlaceTokenizer;
import com.google.gwt.place.shared.Prefix;

public class CCCPlace extends Place
{
    private String cccName = "CCCPlace";

    public CCCPlace()
    {
    }

    public String getCCCName()
    {
        return cccName;
    }

    @Prefix("CCCPlace")
    public static class Tokenizer implements PlaceTokenizer<CCCPlace>
    {
        @Override
        public String getToken(CCCPlace place)
        {
            return place.getCCCName(); //"CCCName"; //place.getCCCName();
        }

        @Override
        public CCCPlace getPlace(String token)
        {
            return new CCCPlace();
        }
    }
}

/src/aaa/bbb/ccc/client/app.css

h1 {
    font-size: 2em;
    font-weight: bold;
    color: #777777;
    margin: 40px 0px 70px;
    text-align: center;
}

.aaaView {
    border-color: black;
    border-width: 2 px;
    background-color: navy;
    width: 75%;
    height: 25%;
}

.viewLabel {
    color:white;
    font-size: 24px; 
    font-style: italic;
    font-weight: bolder; 
    border-width: 2 px;
}

.bbbView {
    border-color: black;
    border-width: 2 px;
    background-color: blue;
    width: 75%;
    height: 25%;
}

.cccView {
    border-color: black;
    border-width: 2 px;
    background-color: lightblue;
    width: 75%;
    height: 25%;
}


.layer1 {
    border-color: red;
    border-width: 2 px;
    background-color: yellow;
    width: 100%;
    height: 33%;
}

.layer2 {
    border-color: teal;
    border-width: 2 px;
    background-color: green;
    width: 100%;
    height: 33%;
}

.layer3 {
    border-color: grey;
    border-width: 2 px;
    background-color: aqua;
    width: 100%;
    height: 33%;
}

.gwt-layer {
    border-color: grey;
    border-width: 2 px;
    background-color: aqua;
    width: 100%;
    height: 33%;    
}

/war/app.html

<!doctype html>
<html>
  <head>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
    <title>app</title>
    <script type="text/javascript" language="javascript" src="app/app.nocache.js"></script>
  </head>
  <body>
    <iframe src="javascript:''" id="__gwt_historyFrame" tabIndex='-1' style="position:absolute;width:0;height:0;border:0"></iframe>
    <noscript>
      <div style="width: 22em; position: absolute; left: 50%; margin-left: -11em; color: red; background-color: white; border: 1px solid red; padding: 4px; font-family: sans-serif">
        Your web browser must have JavaScript enabled
        in order for this application to display correctly.
      </div>
    </noscript>
  </body>
</html>

/war/WEB-INF/web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>app</display-name>
  <welcome-file-list>
    <welcome-file>app.html</welcome-file>
  </welcome-file-list>
</web-app>
4

1 回答 1

1

问题出在你ActivityMapper的 s.

当您转到一个（这是默认位置，因此当您在 URL 中AAAPlace没有任何历史标记时使用的位置）：

  • AAAActivityMapper返回null哪个（给定aaaActivityManager）将隐藏该topOfPage区域
  • BBBActivityMapper返回一个AAAActivity，它将AAAView在middleOfPage区域中显示（单例）
  • CCCActivityMapper返回 another AAAActivity，它将AAAView在bottomOfPage区域中显示 (singleton) 因为AAAView是一个小部件，它一次只能显示在一个地方。而且因为它是一个单例，所以最后一个setWidget会获胜（它会在将小部件添加到新的父级之前从它的前一个父级中删除它）。cccActivityManager因为您在 之后进行了初始化bbbActivityManager，并且事件处理程序是按注册顺序调用的，所以bot将获胜。这给你留下了一个隐藏topOfPage的，一个空的middleOfPage（不是隐藏的，因为mid被调用了一个非空值，但就在这之后bot用相同的小部件调用，因此偷了它middleOfPage把它放进去bottomOfPage），和一个AAAView在bottomOfPage.

无耻插件：看看http://blog.ltgt.net/gwt-21-activities/（以及关于地点和活动的兄弟文章）。我希望它能帮助你理解它是如何工作的。

于 2011-04-06T21:48:56.223 回答