Hello,
I followed the example in that part of the documentation and i have an error. What could be wrong?. Im attaching the error:
java.lang.IllegalArgumentException: Field is already registered
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:122)
at com.haulmont.cuba.web.gui.components.WebFieldGroup.addField(WebFieldGroup.java:165)
at com.haulmont.cuba.web.gui.components.WebFieldGroup.addField(WebFieldGroup.java:160)
at com.company.addondemo.web.customer.CustomerEdit.init(CustomerEdit.java:33)
at com.haulmont.cuba.gui.WindowManager.init(WindowManager.java:1178)
at com.haulmont.cuba.gui.WindowManager.initWrapperFrame(WindowManager.java:1167)
at com.haulmont.cuba.gui.WindowManager.createWindow(WindowManager.java:540)
at com.haulmont.cuba.gui.WindowManager.openEditor(WindowManager.java:819)
at com.haulmont.cuba.web.WebWindowManager.openEditor(WebWindowManager.java:164)
at com.haulmont.cuba.gui.components.WindowDelegate.openEditor(WindowDelegate.java:247)
at com.haulmont.cuba.web.gui.WebWindow.openEditor(WebWindow.java:459)
at com.haulmont.cuba.gui.components.actions.CreateAction.internalOpenEditor(CreateAction.java:305)
at com.haulmont.cuba.gui.components.actions.CreateAction.actionPerform(CreateAction.java:265)
at com.haulmont.cuba.web.gui.components.WebButton.performAction(WebButton.java:44)
at com.haulmont.cuba.web.gui.components.WebButton.lambda$new$61446b05$1(WebButton.java:36)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:510)
at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:200)
at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:163)
at com.vaadin.server.AbstractClientConnector.fireEvent(AbstractClientConnector.java:1037)
at com.vaadin.ui.Button.fireClick(Button.java:377)
at com.haulmont.cuba.web.toolkit.ui.CubaButton.fireClick(CubaButton.java:54)
at com.vaadin.ui.Button$1.click(Button.java:54)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:158)
at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:119)
at com.vaadin.server.communication.ServerRpcHandler.handleInvocation(ServerRpcHandler.java:444)
at com.vaadin.server.communication.ServerRpcHandler.handleInvocations(ServerRpcHandler.java:409)
at com.vaadin.server.communication.ServerRpcHandler.handleRpc(ServerRpcHandler.java:274)
at com.vaadin.server.communication.UidlRequestHandler.synchronizedHandleRequest(UidlRequestHandler.java:90)
at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1436)
at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:385)
at com.haulmont.cuba.web.sys.CubaApplicationServlet.serviceAppRequest(CubaApplicationServlet.java:301)
at com.haulmont.cuba.web.sys.CubaApplicationServlet.service(CubaApplicationServlet.java:192)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at com.haulmont.cuba.web.sys.CubaHttpFilter.handleNotFiltered(CubaHttpFilter.java:108)
at com.haulmont.cuba.web.sys.CubaHttpFilter.doFilter(CubaHttpFilter.java:95)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)