如何添加复合窗口小部件：此窗口小部件的父窗口不实现HasWidgets

时间：2011-09-26 05:14:01

标签： java gwt

我不断抛出一个错误：“这个小部件的父级没有实现HasWidgets。梳理网络（包括stackoverflow），但无法弄清楚是什么问题。我知道它添加下载的方式有问题但是，我不知道它为什么抛出它，或者如何修复它。此外，当我运行应用程序时它首先成功并且只在第二次抛出错误时我尝试访问下载页面。非常感谢任何帮助！

public class SIXPAC implements EntryPoint, HasWidgets
{
    private VerticalPanel mainPanel = new VerticalPanel() ;
    private HorizontalPanel menu = new HorizontalPanel() ;
    private VerticalPanel text = new VerticalPanel() ;
    private SIXPACServiceAsync services = GWT.create( SIXPACService.class ) ;

    public void onModuleLoad() 
    {
        header() ;
        changePage( "about.txt" ) ;
        footer() ;

        RootPanel.get( "sixPac" ).add( mainPanel ) ;
        mainPanel.setWidth("100%");
    }

    public void header()
    {
        menu.add( menu stuff... ) ;
        mainPanel.add( menu ) ;
        mainPanel.add( text ) ;
    }

    public void footer()
    {
        mainPanel.add( footer stuff... ) ;
    }

    public void changePage( String token )
    {
            if( token.equals( "download.txt" ) )        // else its download page and need to set up the forms
        {
            text.clear() ;
            try
            {
                add( new Download() ) ;
            }
            catch( Exception e )
            {
                System.out.println( e ) ;
            }
            text.setStyleName( "contentbox" ) ;
        }
    }

    public void add(Widget w) // tried basic implementation of the HasWidgets methods...
    {
        text.add( w ) ;
    }

    public void clear() 
    {

    }

    public Iterator<Widget> iterator() {
        // TODO Auto-generated method stub
        return null;
    }

    public boolean remove(Widget w) {
        // TODO Auto-generated method stub
        return false;
    }
}

对于下载类，我基本上为了测试而删除了所有内容：

package com.sixpac.website.client;

import java.util.Iterator; 

public class Download extends Composite
{
    private static VerticalPanel verticalPanel = new VerticalPanel();

    public Download() 
    {
        verticalPanel.setStyleName("contentbox");
        initWidget( verticalPanel );
        verticalPanel.setWidth("100%");

        verticalPanel.add( new HTML( "<h1>Download</h1>" ) ) ;

        HorizontalPanel horizontalPanel = new HorizontalPanel();
        horizontalPanel.setHorizontalAlignment(HasHorizontalAlignment.ALIGN_CENTER);
        horizontalPanel.setWidth("100%");
        verticalPanel.add( horizontalPanel ) ;

        System.out.println( "creating new login" ) ;
        Login login = new Login() ;
        System.out.println( "creating new register" ) ;
        Register register = new Register() ;

        horizontalPanel.add( login ) ;
        login.setSize("75%", "310px");
        horizontalPanel.setCellVerticalAlignment(login, HasVerticalAlignment.ALIGN_BOTTOM);
        horizontalPanel.add( register ) ;
        register.setSize("90%", "257px");
        horizontalPanel.setCellVerticalAlignment(register, HasVerticalAlignment.ALIGN_BOTTOM);
        setStyleName("gwt");
    }

    public static void downloadOk()
    {
        verticalPanel.add( new HTML( "<br/><br/>" ) ) ;
        verticalPanel.add( new HTML( "<div class=\"contentbox downloadok\">\n\t\n<p>Thank you for downloading SIXPAC Version 0.5 (Beta).</p>\n<p>Please direct all technical questions and bug-reports to Snehit Prabhu (<a href=\"mailto:snehitp@cs.columbia.edu\">snehitp@cs.columbia.edu</a>)</p>\n\t\n<br />\n\t\n<a href=\"#\" class=\"downloadbutton\">Download SIXPAC</a>\n\n<br /><br />\n</div>\n\n\n</div><!--contentbox-->" ) ) ;
    }
}

堆栈跟踪：

    02:24:14.763 [ERROR] [sixpac] Uncaught exception escaped

com.google.gwt.event.shared.UmbrellaException: One or more exceptions caught, see full set in UmbrellaException#getCauses
    at com.google.gwt.event.shared.HandlerManager.fireEvent(HandlerManager.java:129)
    at com.google.gwt.user.client.ui.Widget.fireEvent(Widget.java:129)
    at com.google.gwt.event.dom.client.DomEvent.fireNativeEvent(DomEvent.java:116)
    at com.google.gwt.user.client.ui.Widget.onBrowserEvent(Widget.java:177)
    at com.google.gwt.user.client.ui.CustomButton.onBrowserEvent(CustomButton.java:698)
    at com.google.gwt.user.client.DOM.dispatchEventImpl(DOM.java:1351)
    at com.google.gwt.user.client.DOM.dispatchEvent(DOM.java:1307)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:337)
    at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:218)
    at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269)
    at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
    at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
    at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:213)
    at sun.reflect.GeneratedMethodAccessor24.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:337)
    at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:218)
    at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNativeVoid(ModuleSpace.java:289)
    at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeVoid(JavaScriptHost.java:107)
    at com.google.gwt.dom.client.DOMImplStandard.dispatchEvent(DOMImplStandard.java)
    at com.google.gwt.dom.client.Element$.dispatchEvent$(Element.java:142)
    at com.google.gwt.user.client.ui.CustomButton.onClick(CustomButton.java:825)
    at com.google.gwt.user.client.ui.PushButton.onClick(PushButton.java:190)
    at com.google.gwt.user.client.ui.CustomButton.onBrowserEvent(CustomButton.java:656)
    at com.google.gwt.user.client.DOM.dispatchEventImpl(DOM.java:1351)
    at com.google.gwt.user.client.DOM.dispatchEvent(DOM.java:1307)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:337)
    at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:218)
    at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269)
    at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
    at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
    at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:213)
    at sun.reflect.GeneratedMethodAccessor24.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:292)
    at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:546)
    at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:363)
    at java.lang.Thread.run(Thread.java:680)
Caused by: java.lang.AssertionError: This UIObject's element is not set; you may be missing a call to either Composite.initWidget() or UIObject.setElement()
    at com.google.gwt.user.client.ui.UIObject.getElement(UIObject.java:527)
    at com.google.gwt.user.client.ui.ComplexPanel.add(ComplexPanel.java:94)
    at com.google.gwt.user.client.ui.VerticalPanel.add(VerticalPanel.java:48)
    at com.sixpac.website.client.SIXPAC.changePage(SIXPAC.java:140)
    at com.sixpac.website.client.SIXPAC$3.onClick(SIXPAC.java:69)
    at com.google.gwt.event.dom.client.ClickEvent.dispatch(ClickEvent.java:54)
    at com.google.gwt.event.dom.client.ClickEvent.dispatch(ClickEvent.java:1)
    at com.google.gwt.event.shared.GwtEvent.dispatch(GwtEvent.java:1)
    at com.google.web.bindery.event.shared.EventBus.dispatchEvent(EventBus.java:40)
    at com.google.web.bindery.event.shared.SimpleEventBus.doFire(SimpleEventBus.java:193)
    at com.google.web.bindery.event.shared.SimpleEventBus.fireEvent(SimpleEventBus.java:88)
    at com.google.gwt.event.shared.HandlerManager.fireEvent(HandlerManager.java:127)
    at com.google.gwt.user.client.ui.Widget.fireEvent(Widget.java:129)
    at com.google.gwt.event.dom.client.DomEvent.fireNativeEvent(DomEvent.java:116)
    at com.google.gwt.user.client.ui.Widget.onBrowserEvent(Widget.java:177)
    at com.google.gwt.user.client.ui.CustomButton.onBrowserEvent(CustomButton.java:698)
    at com.google.gwt.user.client.DOM.dispatchEventImpl(DOM.java:1351)
    at com.google.gwt.user.client.DOM.dispatchEvent(DOM.java:1307)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:337)
    at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:218)
    at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269)
    at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
    at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
    at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:213)
    at sun.reflect.GeneratedMethodAccessor24.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:337)
    at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:218)
    at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNativeVoid(ModuleSpace.java:289)
    at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeVoid(JavaScriptHost.java:107)
    at com.google.gwt.dom.client.DOMImplStandard.dispatchEvent(DOMImplStandard.java)
    at com.google.gwt.dom.client.Element$.dispatchEvent$(Element.java:142)
    at com.google.gwt.user.client.ui.CustomButton.onClick(CustomButton.java:825)
    at com.google.gwt.user.client.ui.PushButton.onClick(PushButton.java:190)
    at com.google.gwt.user.client.ui.CustomButton.onBrowserEvent(CustomButton.java:656)
    at com.google.gwt.user.client.DOM.dispatchEventImpl(DOM.java:1351)
    at com.google.gwt.user.client.DOM.dispatchEvent(DOM.java:1307)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:337)
    at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:218)
    at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269)
    at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
    at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
    at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:213)
    at sun.reflect.GeneratedMethodAccessor24.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:292)
    at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:546)
    at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:363)
    at java.lang.Thread.run(Thread.java:680)

1 个答案:

答案 0 :(得分：1)

问题是verticalPanel在下载类中是静态的。我假设当多次调用时，会导致你的代码initWidget带有错误的引用。尝试删除静态它应该工作。另外，您可以通过将其传递给文本实例来实现其余的haswidget接口方法，就像您实现了add一样。

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