我们在GWT项目中使用GIN进行评估,并且通过构造函数参数进行典型注入,结果很好。我们遇到的困难是现场级别的注入。这些字段总是最终为空。有没有人有一个很好的例子,说明如何正确实现GIN提交级别的注入?GWT GIN字段级别注入
更新:
这是与我们相似的一些示例代码:
public class MVP implements EntryPoint {
public static final HandlerManager EVENT_BUS = new HandlerManager(null);
private final MVPInjector _injector = GWT.create(MVPInjector.class);
public void onModuleLoad() {
// set up layout for module
RootLayoutPanel.get().add(mainPanel);
// initialize presenters
ListPresenter listPresenter = _injector.listPresenter();
DetailPresenter detailPresenter = _injector.detailPresenter();
listPresenter.go(listContainer);
detailPresenter.go(detailContainer);
// simulate data coming in from RPC call
EVENT_BUS.fireEvent(new DataReadyEvent(getData()));
}
}
public class ListPresenter {
private final HandlerManager _eventBus;
private final Map<String, Fruit> _myRecords = new HashMap<String, Fruit>();
private final Display _view;
@Inject
public ListPresenter(Display argView, HandlerManager argEventBus) {
_eventBus = argEventBus;
_view = argView;
}
public void go(HasWidgets argContainer) {
argContainer.clear();
argContainer.add(_view.asWidget());
}
public interface Display {
public Widget asWidget();
public void clear();
public SingleSelectionModel<ViewProxy> getSelectionModel();
public void setData(List<ViewProxy> argData);
}
}
public class DetailPresenter {
private final HandlerManager _eventBus;
private final Display _view;
private Fruit _myRecord;
@Inject
private ImagePresenterFactory _imagePresenterFactory;
@Inject
private TestPresenter _testPresenter;
@Inject
public DetailPresenter(Display argView, HandlerManager argEventBus) {
_view = argView;
_eventBus = argEventBus;
}
public void go(HasWidgets argContainer) {
argContainer.clear();
argContainer.add(_view.asWidget());
if (_testPresenter != null) {
_testPresenter.go();
}
}
public interface Display {
public Widget asWidget();
public HasText getDescriptionControl();
public HasClickHandlers getImageControl();
public HasText getNameControl();
public HasClickHandlers getSaveControl();
public void setEnabledControls(boolean argEnabled);
}
}
public class TestPresenter {
@Inject
HandlerManager _eventBus;
public TestPresenter() {}
public void go() {
if (_eventBus != null) {
_eventBus.toString();
}
else {
// event bus was not injected
}
}
}
@GinModules(MVPModule.class)
public interface MVPInjector extends Ginjector {
DetailPresenter detailPresenter();
ListPresenter listPresenter();
}
public class MVPModule extends AbstractGinModule {
@Provides
@Singleton
public HandlerManager getEventBus() {
return MVP.EVENT_BUS;
}
@Provides
public TestPresenter getTestPresenter() {
return new TestPresenter();
}
@Override
protected void configure() {
bind(ListPresenter.Display.class).to(ListView.class);
bind(DetailPresenter.Display.class).to(DetailView.class);
bind(ImagePresenter.Display.class).to(ImagePopup.class);
install(new GinFactoryModuleBuilder().build(ImagePresenterFactory.class));
}
public interface ImagePresenterFactory {
public ImagePresenter createImagePresenter(ImageResource argImage);
}
}
在上面的代码,我已删除大部分不涉及GIN的代码。 DetailPresenter需要的TestPresenter被成功注入,但TestPresenter要求的HandlerManager始终为空。如您所见,注入的HandlerManager不在构造函数中使用。
而不是试图从构造函数内访问它的值? (很明显,在注入字段之前,对象必须是_constructed_) – 2012-02-27 02:29:12