如何更新primefaces dataTable中的特定单元格

我正在创建一个充满输入字段的动态数据表。有时，当用户在某些输入中插入值时，应更新特定单元格，并且仅更新此单元格。我认为这可能很简单，但却没有成功。
我要更新的单元格是valor total，当其他两个单元格的值发生变化时，应更新此单元格：

I'm creating a dynamic datatable full of input fields. Sometimes when user insert values in some inputs, an specific cell should be updated, and only this cell. I thought it could be simple, but yet didn't make it work. The cell I want update is "valor total", this cell should be updated when the value of two others cell change:

已编辑

我试过f：带有完整id的ajax并得到具有id的组件：lancamentoNF：popupLancamentoNF：tabelaItensNF：0：找不到valorTotalItem。更改为p：ajax并且没有错误发生但它没有更新!!

I've tryied f:ajax with complete id and got "Component with id:lancamentoNF:popupLancamentoNF:tabelaItensNF:0:valorTotalItem not found". Changed to p:ajax and no errors happen but it doesn't update!!

<h:panelGroup id="painelItensNF" layout="block" styleClass="hrgi-div-form aba-lancamento-nf clearfix" style="overflow:auto;">
    <h:panelGroup layout="block" style="width: 1700px;">
        <p:dataTable id="tabelaItensNF" value="#{modeloTabelaDinamicaItemNF.itens}" var="itemEmbrulhado" styleClass="tabelaDinamica" height="174" style="width: 100%;" rowIndexVar="indice">
            ... (some columns)
            <p:column style="width: 5%"
                      headerText="quantidade">
                <hrgi:spinner id="quantidadeItem"
                              value="#{itemEmbrulhado.item.produto.detalheTributavel.quantidade}"
                              dinheiro="false"
                              fator="#{itemEmbrulhado.item.produto.detalheTributavel.unidadeFracionada?0.01:1}"
                              local="pt-BR" min="0.00" width="70">
                    <p:ajax event="change"
                            update="lancamentoNF:popupLancamentoNF:tabelaItensNF:#{indice}:valorTotalItem"
                            listener="#{controladorPopupLancamentoNF.calcularValorTotalItem(itemEmbrulhado)}" global="false" />
                    <f:convertNumber
                            maxFractionDigits="#{itemEmbrulhado.item.produto.detalheTributavel.unidadeFracionada?2:0}"
                            minFractionDigits="#{itemEmbrulhado.item.produto.detalheTributavel.unidadeFracionada?2:0}"
                            locale="pt-BR"
                            for="quantidadeItem"/>
                </hrgi:spinner>
            </p:column>
            <p:column style="width: 5%"
                      headerText="valor unitario">
                <hrgi:spinner id="valorUnitarioItem"
                              value="#{itemEmbrulhado.item.produto.detalheTributavel.valorUnitario}"
                              dinheiro="true" fator="0.01" local="pt-BR" min="0.00" width="70">
                    <p:ajax event="change" 
                            update="lancamentoNF:popupLancamentoNF:tabelaItensNF:#{indice}:valorTotalItem"
                            listener="#{controladorPopupLancamentoNF.calcularValorTotalItem(itemEmbrulhado)}" global="false"/>
                    <f:convertNumber type="currency" currencyCode="BRL" currencySymbol="R$ "
                                     maxFractionDigits="10" minFractionDigits="2" locale="#{cc.attrs.local}"
                                     for="valorUnitarioItem"/>
                </hrgi:spinner>
            </p:column>
            <p:column style="width: 3%"
                      headerText="valor total">
                <h:outputText id="valorTotalItem" value="#{itemEmbrulhado.item.produto.valorTotal}">
                    <f:convertNumber type="currency" currencyCode="BRL" currencySymbol="R$ "
                                     maxFractionDigits="2" minFractionDigits="2" locale="pt-BR"
                                     for="valorUnitarioItem"/>
                </h:outputText>
            </p:column>
            ... (more columns)
        </p:dataTable>
    </h:panelGroup>
</h:panelGroup>

当我用完整的id更新panelGrouppainelItensNF时它会起作用，但是焦点丢失并且用户应该找到他正在努力继续的输入...

It works when I update the panelGroup "painelItensNF" with complete id, but the focus is lost and user should find the input he was working to continue...