html - 错误 : object was provided as `children` instead of a component, 字符串或数字(或它们的列表)

Question

我似乎无法找出开发者控制台中弹出此错误的原因。该脚本在 R 中完美运行并且之前已经工作过。我记得从脚本中删除了一个回调，仅此而已。下面是包含应用程序布局 html 部分的 R 脚本。有人可以帮忙吗？

app$layout(
  htmlDiv(
    children = list(
      htmlDiv(
        list(
          htmlDiv(
            list(
              htmlH3(
                "Maternal Health Dashboard",
                style=list("margin-bottom"= "0px",
                           "text-align" = "center")
              )
            )
          )
        ),
        className="row flex-display",
        id="title",
        style=list("margin-bottom"= "25px")
      ),
      htmlDiv(
        list(
          htmlP("Tabs", className="tabs"),
          dccRadioItems(
            id="tab_buttons",
            options = list(
              list("label"= "General", "value"= "general"),
              list("label"= "Antenatal", "value"= "antenatal_risk"),
              list("label"= "Postnatal ", "value"= "postnatal_details"),
              list("label"= "LBW Child ", "value"= "LBW_details")
            ),
            value="general",
            labelStyle=list("display"= "inline-block","text-align" = "center"
            ),
            className="dcc_control"
          )
        )
      ),
      htmlDiv(
        id = "map-container",
        list(
          htmlP("Map of Maternal Health",
                id = "map-title",
          ),
          dccGraph(figure=fig
          )
        )
      ),
      htmlDiv(
        list(
          htmlP("Total GP "),
          htmlP("Total Sub Centers  "),
          htmlP("Total Villages "),
          htmlP("Total Beneficiary Women  "),
          htmlP("Total Postnatal Women  "),
          htmlP("Total Neonatal Women   ")
        ),
        style= list("display"= "flex","border"= "2px solid powderblue","white-space" = "normal", "justify-content" = "space-around"),
        id="info-container",
        className="row container-display"
      ),
      htmlDiv(
        id = "graph-container",
        list(
          htmlP(id="chart-selector",
                children = "Select chart:"
          ),
          dccDropdown(
            options = list(list("label"= "Total number of infants per Woman ",
                                "value"= "show_absolute_deaths_single_year"),
                           list("label"= "COVID-19 Cases",
                                "value"= "absolute_deaths_all_time"),
                           list("label"= "Total number of post-natal immunizations",
                                "value"= "show_death_rate_single_year"),
                           list("label"= "",
                                "value"= "death_rate_all_time")),
            value="show_death_rate_single_year",
            id="chart-dropdown"
          ),
          dccGraph(
            id = "selected-data"
          )
        )
      ),
      id="mainContainer",
      style = list(
        "position" = "relative",
        "box-sizing" =  "border-box"
      )
    )))


app$run_server()

Answer 1

我用 Python 而不是 R 编写 Dash，但我怀疑行为非常相似，您的问题来自这两个地方:

      htmlDiv(
        id = "map-container",
        list(
          htmlP("Map of Maternal Health",
                id = "map-title",
          ),
          dccGraph(figure=fig
          )
        )
      ),

      htmlDiv(
        id = "graph-container",
        list(
          htmlP(id="chart-selector",
                children = "Select chart:"
          ),
          dccDropdown(
            options = list(list("label"= "Total number of infants per Woman ",
                                "value"= "show_absolute_deaths_single_year"),
                           list("label"= "COVID-19 Cases",
                                "value"= "absolute_deaths_all_time"),
                           list("label"= "Total number of post-natal immunizations",
                                "value"= "show_death_rate_single_year"),
                           list("label"= "",
                                "value"= "death_rate_all_time")),
            value="show_death_rate_single_year",
            id="chart-dropdown"
          ),
          dccGraph(
            id = "selected-data"
          )
        )
      ),

默认情况下，Dash 组件期望 children 属性是第一个传入的东西。在这些情况下，您首先提供了 id，但还没有显式设置 children=，因此它不知道如何处理该组件。要么将它们显式设置为 children，要么将它们设置为组件的第一个对象。