Question

我已经关注了GWTP教程的GettingStarted

http://code.google.com/p/gwt-platform/wiki/GettingStarted

但遗憾的是处理程序无法正常工作，getUiHandlers（）返回null，异常堆栈跟踪与以下内容相同：

查看课程

public class AView extends ViewWithUiHandlers<AUiHandlers> implements APresenter.Display {

    @UiTemplate("AView.ui.xml")
    interface AViewUiBinder extends UiBinder<Widget, AView> {}
    private static AViewUiBinder uiBinder = GWT.create(AViewUiBinder.class);

    @UiField Button saveBtn;
    @UiField Button cancelBtn;

    @UiField DivElement errorDiv;

    private Widget widget;

    @Inject
    public AssetView() {
        widget = uiBinder.createAndBindUi(this);
    }

    public Widget asWidget() {
        return widget;
    }

    // Implementation: Presenter's Display methods
    public void setErrorDivText(String msg) {
        errorDiv.getStyle().setDisplay(Display.BLOCK);
        errorDiv.setInnerText(msg);     
    }

    // Handlers 
    @UiHandler("saveBtn")
    void onSaveButtonClick(ClickEvent event) {
        if(getUiHandlers() != null) {
            getUiHandlers().onSaveButtonClick();
        }
    }

    @UiHandler("cancelBtn")
    void onCancelButtonClick(ClickEvent event) {
        if(getUiHandlers() != null) {
            getUiHandlers().onCancelButtonClick();
        }
    }
}

处理程序界面

public interface AUiHandlers extends UiHandlers {
    void onSaveButtonClick();
    void onCancelButtonClick();
}

演示

public class APresenter extends Presenter<APresenter.Display, APresenter.AssetProxy> implements AUiHandlers {

    public interface Display extends View, HasUiHandlers<AUiHandlers> { 
        public void setErrorDivText(String msg);
    }

    @ProxyStandard
    @NameToken(NameTokens.ASSET)
    public interface AssetProxy extends ProxyPlace<AssetPresenter> {}

    @Inject
    public AssetPresenter(EventBus eventBus, Display view, AssetProxy proxy) {
        super(eventBus, view, proxy);

        getView().setUiHandlers(this);
    }

    @Override
    protected void onBind() {
        super.onBind();
    }

    @Override
    protected void revealInParent() {
        RevealRootContentEvent.fire( this, this );
    }

    public void onSaveButtonClick() {
        getView().setErrorDivText("Save clicked.");
    }

    public void onCancelButtonClick() {
        getView().setErrorDivText("Cancel clicked.");
    }
}

无法理解我犯错误的地方，关于UiHandlers的实现与上述教程链接中的说明相同。

Answer 1

 UiHandlers is not generic; it cannot be parameterized with arguments

当我看到你的处理程序界面时，你已经通过了AUiHandlers类型。我不明白UiHandlers的包结构。它应该是 com.gwtplatform.mvp.client.UiHandlers 。

请检查它的导入。

<强>更新

删除private static AViewUiBinder uiBinder = GWT.create(AViewUiBinder.class);

并传递为构造函数参数

 @Inject
    public AssetView(AViewUiBinder uiBinder) {
        widget = uiBinder.createAndBindUi(this);
    }

GWT平台UiHandlers无法正常工作

1 个答案: