java为什么我的活动会丢失？/奇怪的JavaScript异常

Question

我试图将一个活动从一个儿童节目主持人发送给一个母亲节目主持人。首先，我认为这些事件只会消失。我用try/catch块包围了fireEvent调用，得到了以下错误：

(-:-) 2014-11-06 10:13:26,069 [ERROR] Exception caught: com.google.gwt.core.client.JavaScriptException: (TypeError) __gwt$exception: : Cannot read property 'b' of undefined at Unknown.f2b(mdm-0.js@180:2440) at Unknown.k2b(mdm-0.js@182:2442) at Unknown.t2b(mdm-0.js@51:2448)

我最初的问题太长了，所有的编辑可能让大多数人感到困惑。因此，我构建了一个完全精简的示例，其中仍然存在错误。这将使跟踪错误变得更容易（我希望通过这种方式我可以自己解决它，但我做不到）。 我现在也包括了进口商品，只是为了确保不会漏掉一个细节。 我有一个“母亲演讲者”（mother presenter，我也删去了它），现在它几乎什么都不做：

package testproject.client.application.policies;

import testproject.client.application.ApplicationPresenter;
import testproject.client.application.policies.test.TestPolicyPresenterWidget;
import testproject.client.events.TestPolicyEvent;
import testproject.client.events.TestPolicyEvent.TestPolicyEventHandler;
import testproject.client.place.NameTokens;

import com.allen_sauer.gwt.log.client.Log;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.dom.client.HasClickHandlers;
import com.google.inject.Inject;
import com.google.web.bindery.event.shared.EventBus;
import com.gwtplatform.mvp.client.Presenter;
import com.gwtplatform.mvp.client.View;
import com.gwtplatform.mvp.client.annotations.NameToken;
import com.gwtplatform.mvp.client.annotations.ProxyEvent;
import com.gwtplatform.mvp.client.annotations.ProxyStandard;
import com.gwtplatform.mvp.client.proxy.ProxyPlace;

public class PolicyPresenter extends
        Presenter<PolicyPresenter.MyView, PolicyPresenter.MyProxy> implements TestPolicyEventHandler {

    private TestPolicyPresenterWidget testPolicyDialog;

    @ProxyStandard
    @NameToken(NameTokens.policiesPage)
    public interface MyProxy extends ProxyPlace<PolicyPresenter> {
    }

    public interface MyView extends View {
        HasClickHandlers getTestPolicyButton();
    }

    @Inject
    PolicyPresenter(EventBus eventBus, MyView view, MyProxy proxy,
            TestPolicyPresenterWidget testPolicyDialog) {
        super(eventBus, view, proxy, ApplicationPresenter.SLOT_SetMainContent);
        this.testPolicyDialog = testPolicyDialog;

    }

    @Override
    protected void onBind() {
        super.onBind();

        addRegisteredHandler(TestPolicyEvent.TYPE, this);

        // Handler for add Policy Button
        getView().getTestPolicyButton().addClickHandler(new ClickHandler() {   
              public void onClick(ClickEvent event) {
                Log.debug("Test Policy received click event");
                addToPopupSlot(testPolicyDialog);
              }
            });

    }

    @Override
    protected void onReveal() {
        super.onReveal();
    }

    @Override
    protected void onReset() {
        super.onReset();

    }

    @ProxyEvent
    @Override
    public void onTestPolicyEvent(TestPolicyEvent event) {
        Log.debug("TestPolicyCreatedEvent caught");
    }


}

我添加了评论中提到的@ProxyEvent符号，只是为了确保

这种观点现在也被大大削弱了：

package testproject.client.application.policies;

import javax.inject.Inject;

import testproject.client.model.ContainerPolicy;
import testproject.client.resources.MDMTCellTableResources;

import com.google.gwt.core.client.GWT;
import com.google.gwt.event.dom.client.HasClickHandlers;
import com.google.gwt.uibinder.client.UiBinder;
import com.google.gwt.uibinder.client.UiField;
import com.google.gwt.user.cellview.client.CellTable;
import com.google.gwt.user.cellview.client.CellTable.Resources;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.Widget;
import com.google.gwt.view.client.ProvidesKey;
import com.gwtplatform.mvp.client.ViewImpl;

public class PolicyView extends ViewImpl implements PolicyPresenter.MyView {

    private static final int pageSize = 15;

    interface Binder extends UiBinder<Widget, PolicyView> {
    }

    private static final ProvidesKey<ContainerPolicy> KEY_PROVIDER = new ProvidesKey<ContainerPolicy>() {
        @Override
        public Object getKey(ContainerPolicy item) {
            return item.getId();
        }
    };

    @UiField
    Button testPolicyButton;

    @UiField(provided=true)
    CellTable<ContainerPolicy> cellTable = new CellTable<ContainerPolicy>(pageSize, (Resources)GWT.create(MDMTCellTableResources.class), KEY_PROVIDER);

    public HasClickHandlers getTestPolicyButton() {
        return testPolicyButton;
    }


    public CellTable<ContainerPolicy> getCellTable() {
         return cellTable;
    }

    @Inject
    PolicyView(Binder uiBinder) {
        initWidget(uiBinder.createAndBindUi(this));
    }
}

现在，当我单击按钮时，会显示另一个演示者，使用addToPopupSlot(testPolicyDialog);

我的孩子演示器（widget）现在也完全精简了： 主持人：

package testproject.client.application.policies.test;

import testproject.client.events.TestPolicyEvent;
import testproject.client.model.ClientModelProvider;

import com.allen_sauer.gwt.log.client.Log;
import com.google.gwt.user.client.ui.CheckBox;
import com.google.gwt.user.client.ui.TextBox;
import com.google.inject.Inject;
import com.google.web.bindery.event.shared.EventBus;
import com.gwtplatform.mvp.client.HasUiHandlers;
import com.gwtplatform.mvp.client.PopupView;
import com.gwtplatform.mvp.client.PresenterWidget;
import com.gwtplatform.mvp.client.annotations.ProxyEvent;

public class TestPolicyPresenterWidget extends PresenterWidget<TestPolicyPresenterWidget.MyView> implements
        TestPolicyUiHandlers {

    private final EventBus eventBus;

    public interface MyView extends PopupView, HasUiHandlers<TestPolicyUiHandlers> {
        CheckBox getEnabled();
        CheckBox getEnforced();
        TextBox getPolicyType();
        TextBox getContainerGroup();
    }

    @Inject
    TestPolicyPresenterWidget(EventBus eventBus, MyView view,
            ClientModelProvider clientModelProvider) {
        super(eventBus, view);
        this.eventBus = eventBus;

    }

    protected void onBind() {
        super.onBind();
        Log.debug("EventBus in NewPolicyPresenter is " + eventBus.toString()  + " with hashcode " + eventBus.hashCode());

    }

    @Override
    protected void onReveal() {
        super.onReveal();
    }


    @ProxyEvent
    @Override
    public void createPolicy() {
        try {
            Log.debug("Click event on ok Button in add policy dialog caught. ");
            Log.debug("Firing Event");
            eventBus.fireEvent(new TestPolicyEvent());
            Log.debug("Firing Event, without stating the eventBus:");
            fireEvent(new TestPolicyEvent());
        } catch (Exception e) {
            Log.error("Exception caught: ",e);
        }
    }
}

视图：

package testproject.client.application.policies.test;

import testproject.client.model.ContainerPolicy;

import com.google.gwt.editor.client.Editor;
import com.google.gwt.editor.client.SimpleBeanEditorDriver;
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.Button;
import com.google.gwt.user.client.ui.CheckBox;
import com.google.gwt.user.client.ui.PopupPanel;
import com.google.gwt.user.client.ui.TextBox;
import com.google.inject.Inject;
import com.google.web.bindery.event.shared.EventBus;
import com.gwtplatform.mvp.client.PopupViewWithUiHandlers;

public class TestPolicyView extends PopupViewWithUiHandlers<TestPolicyUiHandlers> implements
        TestPolicyPresenterWidget.MyView, Editor<ContainerPolicy> {
    interface Binder extends UiBinder<PopupPanel, TestPolicyView> {
    }

    public interface Driver extends SimpleBeanEditorDriver<ContainerPolicy, TestPolicyView> {
    }


    @UiField
    CheckBox enabled;
    @UiField
    CheckBox enforced;
    @UiField
    TextBox policyType;

    @UiField
    TextBox containerGroup;

    @UiField
    Button okButton;
    @UiField
    Button cancelButton;

    @Inject
    TestPolicyView(Binder uiBinder,EventBus eventBus) {
        super(eventBus);
        initWidget(uiBinder.createAndBindUi(this));
    }


    @UiHandler("okButton")
    void okButtonClicked(ClickEvent event) {
        getUiHandlers().createPolicy();

        hide();
    }

    @UiHandler("cancelButton")
    void cancelButtonClicked(ClickEvent event) {
        hide();
    }
    @Override
    public CheckBox getEnabled() {
        return enabled;
    }

    @Override
    public CheckBox getEnforced() {
        return enforced;
    }

    @Override
    public TextBox getPolicyType() {
        return policyType;
    }

    @Override
    public TextBox getContainerGroup() {
        return containerGroup;
    }
}

而且，由于它在某种程度上与JS有关，所以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">

    <g:DialogBox modal="false">
        <g:caption>
            <b>Policy</b>
        </g:caption>
        <g:HTMLPanel>

            <div class="locked">
                <div class="lockedpanel float-wrapper container-edit">

                    <!-- Device block -->
                    <div class="panel panel-default">

                        <div class="panel-heading">
                            <h4 class="panel-title">Policy</h4>
                        </div>

                        <div class="panel-body">

                                <form class="form-bordered">
                                    <div class="form-group">

                                        <label class="col-sm-4 control-label">Enabled</label>
                                        <div class="col-sm-8">
                                            <g:CheckBox ui:field="enabled" styleName="form-control input-sm"/>
                                        </div>

                                        <label class="col-sm-4 control-label">Enforced</label>
                                        <div class="col-sm-8">
                                            <g:CheckBox ui:field="enforced" styleName="form-control input-sm" />
                                        </div>

                                        <label class="col-sm-4 control-label">Policy Type</label>
                                        <div class="col-sm-8">
                                            <g:TextBox ui:field="policyType" styleName="form-control input-sm"/>
                                        </div>

                                        <label class="col-sm-4 control-label">Container Group</label>
                                        <div class="col-sm-8">
                                            <g:TextBox ui:field="containerGroup" styleName="form-control input-sm"/>
                                        </div>

                                    </div><!-- form-group -->
                                </form>

                        </div><!-- panel-body -->
                    </div><!-- panel-default -->

                    <div class="float-right">
                        <g:Button ui:field="okButton" styleName="btn btn-primary btn-bordered">Ok</g:Button>
                        <g:Button ui:field="cancelButton" styleName="btn btn-primary btn-bordered">Cancel</g:Button>
                    </div>

                </div><!-- lockedpanel -->
            </div>

        </g:HTMLPanel>
    </g:DialogBox>
</ui:UiBinder>

我在ApplicationModule中这样绑定演示者：

package testproject.client.application;

...


public class ApplicationModule extends AbstractPresenterModule {
    @Override
    protected void configure() {
        install(new UiModule());

        // Application Presenters
        bindPresenter(ApplicationPresenter.class, ApplicationPresenter.MyView.class, ApplicationView.class,
                      ApplicationPresenter.MyProxy.class);
...
        bindPresenter(PolicyPresenter.class, PolicyPresenter.MyView.class, PolicyView.class, PolicyPresenter.MyProxy.class);
        bindSingletonPresenterWidget(TestPolicyPresenterWidget.class, TestPolicyPresenterWidget.MyView.class,
                TestPolicyView.class);}
}

当我试图访问createPolicy方法中的任何对象时，就会出现上述错误。例如，当我称之为：

    Log.debug("Click event on ok Button in add policy dialog caught. ");
    Log.debug("Firing Event");
    eventBus.fireEvent(new TestPolicyEvent());

我得到了错误。我是否使用eventBus并不重要。fireEvent或fireEvent。当我试图访问其他对象时也会发生这种情况。所以我猜问题其实与事件处理无关。但这是什么原因呢

感谢你迄今为止的帮助，感谢你花时间阅读这篇文章