如何解决Vaadin：如何清除 FormLayout 字段中的整数/数字值？
在我的 spring-boot vaadin 应用程序中，我有一个扩展 FormLayout 的组件，其中一些字段绑定到一个实体。 要使用表单创建一个新对象，我首先创建： new Entity() 然后我在绑定器中为它设置 bean： binder.setBean（新实体作为参数）。 第一个字段的类型是：IntegerField（用于整数输入）和 NumberField（用于双输入）。这些字段填充为 0 - 表示整数，0.0 表示双精度。我想清除这些字段中的值，以便它们准备好填充新数据。
我该怎么做？
我试过了：
binder.getFields().forEach(f -> f.clear());
但我最终在方法上出现了 NullPointerException：clear()。
调试器看起来像这样：
binder = 'this' is not available 显示 - 可能的解决方案是什么？
也许有更好的方法来清理表单字段？？？
日志如下：
java.lang.NullPointerException: null
at com.vaadin.flow.data.binder.Binder$BindingImpl.lambda$writeFieldValue$5169480d$1(Binder.java:1247) ~[flow-data-2.4.1.jar:2.4.1]
at com.vaadin.flow.data.binder.SimpleResult.handle(SimpleResult.java:77) ~[flow-data-2.4.1.jar:2.4.1]
at com.vaadin.flow.data.binder.ValidationResultWrap.handle(ValidationResultWrap.java:81) ~[flow-data-2.4.1.jar:2.4.1]
at com.vaadin.flow.data.binder.Result.ifOk(Result.java:145) ~[flow-data-2.4.1.jar:2.4.1]
at com.vaadin.flow.data.binder.Binder$BindingImpl.writeFieldValue(Binder.java:1247) ~[flow-data-2.4.1.jar:2.4.1]
at com.vaadin.flow.data.binder.Binder$BindingImpl.access$1600(Binder.java:1032) ~[flow-data-2.4.1.jar:2.4.1]
at com.vaadin.flow.data.binder.Binder.lambda$doWriteIfValid$4(Binder.java:1955) ~[flow-data-2.4.1.jar:2.4.1]
at java.base/java.lang.Iterable.forEach(Iterable.java:75) ~[na:na]
at com.vaadin.flow.data.binder.Binder.doWriteIfValid(Binder.java:1954) ~[flow-data-2.4.1.jar:2.4.1]
at com.vaadin.flow.data.binder.Binder.handleFieldValueChange(Binder.java:1560) ~[flow-data-2.4.1.jar:2.4.1]
at com.vaadin.flow.data.binder.Binder$BindingImpl.handleFieldValueChange(Binder.java:1230) ~[flow-data-2.4.1.jar:2.4.1]
at com.vaadin.flow.data.binder.Binder$BindingImpl.lambda$new$f9b94f89$1(Binder.java:1068) ~[flow-data-2.4.1.jar:2.4.1]
at com.vaadin.flow.component.internal.AbstractFieldSupport.lambda$addValueChangeListener$828eca10$1(AbstractFieldSupport.java:96) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.component.ComponentEventBus.fireEventForListener(ComponentEventBus.java:205) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.component.ComponentEventBus.fireEvent(ComponentEventBus.java:194) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.component.Component.fireEvent(Component.java:359) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.component.ComponentUtil.fireEvent(ComponentUtil.java:386) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.component.internal.AbstractFieldSupport.setValue(AbstractFieldSupport.java:207) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.component.internal.AbstractFieldSupport.setValue(AbstractFieldSupport.java:133) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.component.AbstractField.setValue(AbstractField.java:181) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.component.textfield.AbstractNumberField.setValue(AbstractNumberField.java:293) ~[vaadin-text-field-flow-2.3.1.jar:na]
at com.vaadin.flow.component.textfield.AbstractNumberField.setValue(AbstractNumberField.java:38) ~[vaadin-text-field-flow-2.3.1.jar:na]
at com.vaadin.flow.component.HasValue.clear(HasValue.java:179) ~[flow-server-2.4.1.jar:2.4.1]
at com.jg.marketing.ui.views.list.NewReceiverForm.lambda$clearForm$0(NewReceiverForm.java:107) ~[classes/:na]
at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183) ~[na:na]
at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195) ~[na:na]
at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1655) ~[na:na]
at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484) ~[na:na]
at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474) ~[na:na]
at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150) ~[na:na]
at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173) ~[na:na]
at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:na]
at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497) ~[na:na]
at com.jg.marketing.ui.views.list.NewReceiverForm.clearForm(NewReceiverForm.java:107) ~[classes/:na]
at com.jg.marketing.ui.views.list.NewReceiverForm.lambda$createButtonsLayout$2f54d9f7$4(NewReceiverForm.java:101) ~[classes/:na]
at com.vaadin.flow.component.ComponentEventBus.fireEventForListener(ComponentEventBus.java:205) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.component.ComponentEventBus.handleDomEvent(ComponentEventBus.java:373) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.component.ComponentEventBus.lambda$addDomTrigger$dd1b7957$1(ComponentEventBus.java:264) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.internal.nodefeature.ElementListenerMap.lambda$fireEvent$2(ElementListenerMap.java:441) ~[flow-server-2.4.1.jar:2.4.1]
at java.base/java.util.ArrayList.forEach(ArrayList.java:1541) ~[na:na]
at com.vaadin.flow.internal.nodefeature.ElementListenerMap.fireEvent(ElementListenerMap.java:441) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.server.communication.rpc.EventRpcHandler.handleNode(EventRpcHandler.java:59) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.server.communication.rpc.AbstractRpcInvocationHandler.handle(AbstractRpcInvocationHandler.java:64) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.server.communication.ServerRpcHandler.handleInvocationData(ServerRpcHandler.java:409) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.server.communication.ServerRpcHandler.lambda$handleInvocations$1(ServerRpcHandler.java:390) ~[flow-server-2.4.1.jar:2.4.1]
at java.base/java.util.ArrayList.forEach(ArrayList.java:1541) ~[na:na]
at com.vaadin.flow.server.communication.ServerRpcHandler.handleInvocations(ServerRpcHandler.java:390) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.server.communication.ServerRpcHandler.handleRpc(ServerRpcHandler.java:317) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.server.communication.UidlRequestHandler.synchronizedHandleRequest(UidlRequestHandler.java:89) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:40) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.server.VaadinService.handleRequest(VaadinService.java:1545) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.server.VaadinServlet.service(VaadinServlet.java:247) ~[flow-server-2.4.1.jar:2.4.1]
at com.vaadin.flow.spring.SpringServlet.service(SpringServlet.java:111) ~[vaadin-spring-12.3.2.jar:na]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.39.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:712) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:459) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:352) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.springframework.web.servlet.mvc.ServletForwardingController.handleRequestInternal(ServletForwardingController.java:141) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:177) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:52) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:652) ~[tomcat-embed-core-9.0.39.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.39.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:320) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:126) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:90) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:118) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:158) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:200) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:92) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:77) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:215) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:358) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:271) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]
第 107 行指向 clear() 方法。
下面是我的 FormLayout，我想清除的字段在哪里。
package com.jg.marketing.ui.views.list;
import com.jg.marketing.backend.entity.Receiver;
import com.vaadin.flow.component.ComponentEvent;
import com.vaadin.flow.component.ComponentEventListener;
import com.vaadin.flow.component.Key;
import com.vaadin.flow.component.button.Button;
import com.vaadin.flow.component.button.ButtonVariant;
import com.vaadin.flow.component.formlayout.FormLayout;
import com.vaadin.flow.component.icon.Icon;
import com.vaadin.flow.component.icon.VaadinIcon;
import com.vaadin.flow.component.orderedlayout.HorizontalLayout;
import com.vaadin.flow.component.textfield.IntegerField;
import com.vaadin.flow.component.textfield.NumberField;
import com.vaadin.flow.component.textfield.TextField;
import com.vaadin.flow.data.binder.Binder;
import com.vaadin.flow.data.validator.DoubleRangeValidator;
import com.vaadin.flow.data.validator.IntegerRangeValidator;
import com.vaadin.flow.shared.Registration;
public class NewReceiverForm extends FormLayout {
IntegerField sapNumber = new IntegerField("SAP","fill with a number");
NumberField score = new NumberField("Realizacja %","i.e.: 99.99 ");
TextField type = new TextField("Segment","fill with SEGMENT");
TextField city = new TextField("Miasto","fill city");
TextField postCode = new TextField("Kod pocztowy","i.e..: 12-345");
TextField street = new TextField("Ulica","fill street");
TextField streetNumber = new TextField("Nr budynku","np.: 125 B");
TextField phoneNumber = new TextField("Nr kontaktowy","phonenumber");
Button save = new Button("Dodaj",new Icon(VaadinIcon.PLUS));
Button delete = new Button("Usuń",new Icon(VaadinIcon.MINUS));
Button close = new Button("Anuluj",new Icon(VaadinIcon.CLOSE));
Button reset = new Button("Wyczyść",new Icon(VaadinIcon.ERASER));
Binder<Receiver> binder = new Binder<>(Receiver.class);
public NewReceiverForm() {
addClassName("new-receiver-form");
binder.forField(sapNumber)
.asRequired("Fill with number: min. 70000000 - max.79999999")
.withValidator(new IntegerRangeValidator("YOu entered a wrong number SAP! 70000000 - 79999999",70000000,79999999))
.bind(Receiver::getSapNumber,Receiver::setSapNumber);
binder.forField(score)
.asRequired("Fill percentage i.e.: 99.99")
.withValidator(new DoubleRangeValidator("min. 0 max. 100",0.00,100.00))
.bind(Receiver::getScore,Receiver::setScore);
binder.forField(type)
.asRequired("fill segment")
.bind(Receiver::getType,Receiver::setType);
binder.forField(city)
.asRequired("fill city")
.bind(Receiver::getCity,Receiver::setCity);
binder.forField(postCode)
.asRequired("fill postcode")
.bind(Receiver::getPostCode,Receiver::setPostCode);
binder.forField(street)
.asRequired("fill street")
.bind(Receiver::getStreet,Receiver::setStreet);
binder.forField(streetNumber)
.asRequired("fill street number")
.bind(Receiver::getStreetNumber,Receiver::setStreetNumber);
binder.forField(phoneNumber)
.asRequired("fill phonenumber")
.bind(Receiver::getPhoneNumber,Receiver::setPhoneNumber);
add(
sapNumber,score,type,city,postCode,street,streetNumber,phoneNumber,createButtonsLayout()
);
}
public void setReceiver(Receiver receiver) {
binder.setBean(receiver);
}
private HorizontalLayout createButtonsLayout() {
save.addThemeVariants(ButtonVariant.LUMO_PRIMARY);
save.addClickShortcut(Key.ENTER);
save.addClickListener(buttonClickEvent -> validateAndSave());
delete.addThemeVariants(ButtonVariant.LUMO_ERROR);
delete.addClickListener(buttonClickEvent -> fireEvent(new DeleteEvent(this,binder.getBean())));
close.addThemeVariants(ButtonVariant.LUMO_TERTIARY);
close.addClickShortcut(Key.ESCAPE);
close.addClickListener(buttonClickEvent -> fireEvent(new CloseEvent(this)));
binder.addStatusChangeListener(evt -> save.setEnabled(binder.isValid()));
reset.addClickListener(buttonClickEvent -> clearForm());
return new HorizontalLayout(save,delete,reset,close);
}
// Clear fields in form
private void clearForm() {
binder.getFields().forEach(f -> f.clear());
}
private void validateAndSave() {
if (binder.isValid()) {
fireEvent(new SaveEvent(this,binder.getBean()));
}
}
// Events
public static abstract class NewReceiverFormEvent extends ComponentEvent<NewReceiverForm> {
private Receiver receiver;
protected NewReceiverFormEvent(NewReceiverForm source,Receiver receiver) {
super(source,false);
this.receiver = receiver;
}
public Receiver getReceiver() {
return receiver;
}
}
public static class SaveEvent extends NewReceiverFormEvent {
SaveEvent(NewReceiverForm source,receiver);
}
}
public static class DeleteEvent extends NewReceiverFormEvent {
DeleteEvent(NewReceiverForm source,Receiver contact) {
super(source,contact);
}
}
public static class CloseEvent extends NewReceiverFormEvent {
CloseEvent(NewReceiverForm source) {
super(source,null);
}
}
public static class ResetEvent extends NewReceiverFormEvent {
ResetEvent(NewReceiverForm source) {
super(source,null);
}
}
public <T extends ComponentEvent<?>> Registration addListener(Class<T> eventType,ComponentEventListener<T> listener) {
return getEventBus().addListener(eventType,listener);
}
}
解决方法
不是清除表单上的字段，而是将实体实例属性设置为 null。您始终可以将 Integer、Big decimal 等属性设置为 null。
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