试图将事件总线注入(inject)组件，但我得到了 “没有默认(零参数)构造函数。”错误。任何线索我是什么 做错了吗？ GIN 非常新，所以它可能是微不足道的..
这是我的代码:
模块:
public class MyWidgetClientModule extends AbstractGinModule {
protected void configure() {
bind(EventBus.class).to(SimpleEventBus.class).in(Singleton.class);
}
}
注入(inject)器:
@GinModules(MyWidgetClientModule.class)
public interface MyWidgetGinjector extends Ginjector {
}
和我试图注入(inject)的组件:
public class I18NLabel extends Label implements ChangeLanguageEventHandler{
private final SimpleEventBus eventBus;
private String key;
@Inject
public I18NLabel(SimpleEventBus eventBus) {
this.eventBus = eventBus;
}
...
它给了我这个错误日志:
00:00:45.767 [DEBUG] Rebinding com.test.fdc.gui.gwt.client.customer.CustomerDetailView.Binder
00:00:45.767 [DEBUG] Invoking generator com.google.gwt.uibinder.rebind.UiBinderGenerator
00:00:45.767 [ERROR] com.test.fdc.gui.gwt.client.content.i18n.I18NLabel has no default (zero args) constructor. To fix this, you can define a @UiFactory method on the UiBinder's owner, or annotate a constructor of I18NLabel with @UiConstructor.
00:00:45.767 [ERROR] Deferred binding failed for 'com.test.fdc.gui.gwt.client.customer.CustomerDetailView.Binder'; expect subsequent failures
00:00:45.767 [ERROR] Uncaught exception escaped
java.lang.ExceptionInInitializerError: null
at com.test.fdc.gui.gwt.client.FDC$4.onSuccess(FDC.java:394)
at com.test.fdc.gui.gwt.client.FDC$4.onSuccess(FDC.java:1)
at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:215)
at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:287)
at com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395)
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:157)
at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:326)
at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:207)
at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:126)
at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:562)
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:214)
at sun.reflect.GeneratedMethodAccessor22.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:157)
at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:281)
at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:531)
at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:352)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.RuntimeException: Deferred binding failed for 'com.test.fdc.gui.gwt.client.customer.CustomerDetailView$Binder' (did you forget to inherit a required module?)
at com.google.gwt.dev.shell.GWTBridgeImpl.create(GWTBridgeImpl.java:53)
at com.google.gwt.core.client.GWT.create(GWT.java:97)
at com.test.fdc.gui.gwt.client.customer.CustomerDetailView.(CustomerDetailView.java:34)
at com.test.fdc.gui.gwt.client.FDC$4.onSuccess(FDC.java:394)
at com.test.fdc.gui.gwt.client.FDC$4.onSuccess(FDC.java:1)
at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:215)
at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:287)
at com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395)
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:157)
at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:326)
at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:207)
at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:126)
at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:562)
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:214)
at sun.reflect.GeneratedMethodAccessor22.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:157)
at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:281)
at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:531)
at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:352)
at java.lang.Thread.run(Thread.java:619)
Caused by: com.google.gwt.core.ext.UnableToCompleteException: (see previous log entries)
at com.google.gwt.dev.shell.ModuleSpace.rebind(ModuleSpace.java:596)
at com.google.gwt.dev.shell.ModuleSpace.rebindAndCreate(ModuleSpace.java:456)
at com.google.gwt.dev.shell.GWTBridgeImpl.create(GWTBridgeImpl.java:49)
at com.google.gwt.core.client.GWT.create(GWT.java:97)
at com.test.fdc.gui.gwt.client.customer.CustomerDetailView.(CustomerDetailView.java:34)
at com.test.fdc.gui.gwt.client.FDC$4.onSuccess(FDC.java:394)
at com.test.fdc.gui.gwt.client.FDC$4.onSuccess(FDC.java:1)
at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:215)
at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:287)
at com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395)
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:157)
at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:326)
at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:207)
at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:126)
at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:562)
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:214)
at sun.reflect.GeneratedMethodAccessor22.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:157)
at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:281)
at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:531)
at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:352)
at java.lang.Thread.run(Thread.java:619)
最佳答案
当您在 UiBinder 中声明一个小部件时，GWT 会尝试使用默认的零参数构造函数对其进行实例化。由于您的新 Widget 没有无参数构造函数，因此 UiBinder 方法失败。
您可以查看@UiConstructor 和@UiField(provided=true) 注释，但这两者都不会为您提供非常优雅的解决方案。您最好以编程方式声明您的小部件并将其插入到您的 Java 布局中。如果你确实想继续使用 UiBinder，你可以做类似的事情
@UiField(provided=true)
protected I18NLabel theLabel;
public MyCompositeWidgetDefinedByUiBinder()
{
theLabel = new I18NLabel(eventBusToInject);
initWidget(uiBinder.createAndBindUI(this));
}
但除此之外，没有其他优雅的方式通过 UiBinder 注入(inject)对象。
关于gwt - 注入(inject) EventBus GWT，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/4070740/