将对象传递给在uibinder中定义的小部件的构造函数 [英] passing an object to the constructor of a widget defined in uibinder

问题描述

我试图将我的应用程序的EventBus传递给通过其构造函数在UiBinder中声明的小部件。我使用@UiConstructor注释来标记一个接受EventBus的构造函数，但我不知道如何从我的ui.xml代码中实际引用该对象。

就是说，我需要像

WidgetThatNeedsAnEventBus.java

  public class WidgetThatNeedsAnEventBus extends Composite 
 {
 private EventBus eventBus; 
 
 @UiConstructor 
 public WidgetThatNeedsAnEventBus（EventBus eventBus）
 {
 this.eventBus = eventBus; 
} 
} 
  

TheUiBinderThatWillDeclareAWTNAEB.ui.xml

 < g：HTMLPanel> 
< c：WidgetThatNeedsAnEventBus eventBus = _I_need_some_way_to_specify_my_apps_event_bus_ /> 
< / g：HTMLPanel> 
  

将静态值传递给WidgetThatNeedsAnEventBus并没有问题，我可以使用工厂方法创建一个新的EventBus对象。但我需要的是通过我已经存在的EventBus。

有没有办法在UiBinder中引用已经存在的对象？

解决方案

我最终的解决方案是使用 @UiField（provided = true）使用变量初始化。然后，我只是在Java中调用了构件，然后在调用 initWidget 之前

例如：

  public class ParentWidget extends Composite 
 {
 @UiField（provided = true）
保护ChildWidget子项; 
 $ b $公共ParentWidget（Object theObjectIWantToPass）
 {
 child = new ChildWidget（theObjectIWantToPass）; // _ before_ initWidget 
 initWidget（uiBinder.create（this））; 
 
 //继续正常初始化！ 
} 
} 
  

I'm trying to pass my app's EventBus to a widget declared in a UiBinder via its constructor. I'm using the @UiConstructor annotation to mark a constructor that accepts the EventBus, but I don't know how to actually reference the object from my ui.xml code.

That is, I need something like

WidgetThatNeedsAnEventBus.java

public class WidgetThatNeedsAnEventBus extends Composite
{
    private EventBus eventBus;

    @UiConstructor
    public WidgetThatNeedsAnEventBus(EventBus eventBus)
    {
        this.eventBus = eventBus;
    }
}

TheUiBinderThatWillDeclareAWTNAEB.ui.xml

<g:HTMLPanel>
    <c:WidgetThatNeedsAnEventBus eventBus=_I_need_some_way_to_specify_my_apps_event_bus_ />
</g:HTMLPanel>

I have no problem passing a static value to the WidgetThatNeedsAnEventBus, and I can use a factory method to create a new EventBus object. But what I need is to pass my app's already-existing EventBus.

Is there a way to refer to already-existing objects in a UiBinder?

解决方案

My eventual solution was to use @UiField(provided=true) on the widget I needed to initialize with a variable.

Then, I just constructed the widget myself in Java, before calling initWidget on the parent.

For example:

public class ParentWidget extends Composite
{
    @UiField(provided=true)
    protected ChildWidget child;

    public ParentWidget(Object theObjectIWantToPass)
    {
        child = new ChildWidget(theObjectIWantToPass);  //_before_ initWidget
        initWidget(uiBinder.create(this));

        //proceed with normal initialization!
    }
}

这篇关于将对象传递给在uibinder中定义的小部件的构造函数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！