如何使方法在表单生成器中的值更改上运行？

Question

当前，我们有一个方法addLabelToNode可以在控件的值更改（例如下拉选择等）上运行。目前，该方法是从文件DataModel.scala中的notifyValueChange调用的。 这在Form Runner中工作正常，但是如果我们为Form Builder中的控件设置默认值，它将不会运行addLabelToNode。

notifyValueChange：

  private def notifyValueChange(
                                 containingDocument: XFormsContainingDocument,
                                 nodeInfo: NodeInfo,
                                 oldValue: String,
                                 newValue: String,
                                 isCalculate: Boolean,
                                 collector: XFormsEvent ⇒ Unit
                               ) =
    Option(containingDocument.getInstanceForNode(nodeInfo)) match {
      case Some(modifiedInstance) ⇒
        // Tell the model about the value change
        try {
          val nodeName = nodeInfo.name
          var objectControl: XFormsObject = null
          try {
            objectControl = containingDocument.resolveObjectById(containingDocument.getEffectiveId, nodeName + "-control", null)
          } catch {
            case _: NullPointerException =>
            case e: Exception => e.printStackTrace(); XFormsServer.logger.warn(e.getMessage);
          }
          objectControl match {
            case selectControl: XFormsSelect1Control =>
              addLabelToNode(selectControl, newValue, nodeInfo)
            case valueComponentControl: XFormsValueComponentControl =>
              valueComponentControl.children.head match {
                case componentRootControl: XXFormsComponentRootControl =>
                  componentRootControl.children.foreach {
                    case wrappedSelectControl: XFormsSelect1Control =>
                      addLabelToNode(wrappedSelectControl, newValue, nodeInfo)
                    case _ =>
                  }
                case _ =>
              }
            case _ =>
          }
        } catch {
          case e: Exception => e.printStackTrace(); XFormsServer.logger.warn(e.getMessage);
        }
// rest of the method

addLabelToNode：

  private def addLabelToNode(control: XFormsSelect1Control, newValue: String, nodeInfo: NodeInfo): Unit = {
    try {
      val name = control.element.getQName.getName
      if ("select1".equals(name)) {
        val label = control.getItemset.selectedItems(newValue).head.label.label
        XFormsAPI.ensureAttribute(nodeInfo, new QName("label", null, null), label)
      } else if ("select".equals(name)) {
        val stringList = new util.ArrayList[String]()
        val newValueArray = newValue.split(" ")
        newValueArray.foreach(
          v => {
            val item = control.getItemset.selectedItems(newValue).find(i => i.value == v).get
            stringList.add(item.label.label)
          }
        )
        val label = stringList.toArray.mkString(" ")
        XFormsAPI.ensureAttribute(nodeInfo, new QName("label", null, null), label)
      }
    } catch {
      case _: NoSuchElementException => XFormsAPI.ensureAttribute(nodeInfo, new QName("label", null, null), "")
    }
  }