flexdashboard中rAmCharts4图表第二页显示异常问题求助

flexdashboard采用单页架构，初始加载时仅渲染并激活第一页的DOM元素，第二页内容处于隐藏状态。rAmCharts4基于React构建，图表初始化时需要定位到对应的DOM节点，但第二页的图表容器在初始化阶段并未被纳入DOM树解析，因此触发"The deferred DOM Node could not be resolved to a valid node"警告，导致渲染失败。

方案一：静态仪表盘适配（无需Shiny） #

为每个图表指定唯一elementId，并通过htmlwidgets::onRender添加页面切换监听，确保图表在对应页面激活时完成初始化：

### Chart B

```{r}
dat <- data.frame(
  country = c("USA", "China", "Japan", "Germany", "UK", "France"),
  visits = c(3025, 1882, 1809, 1322, 1122, 1114)
)

# 创建图表并指定唯一ID
chart <- amBarChart(
  data = dat, data2 = dat,
  width = "600px",
  category = "country", values = "visits",
  draggable = TRUE,
  tooltip = "[bold font-style:italic #ffff00]{valueY.value.formatNumber('#,###.')}[/]",
  chartTitle = amText(text = "Visits per country", fontSize = 22, color = "orangered"),
  xAxis = list(title = amText(text = "Country", color = "maroon")),
  yAxis = list(
    title = amText(text = "Visits", color = "maroon"),
    gridLines = amLine(color = "orange", width = 1, opacity = 0.4)
  ),
  yLimits = c(0, 4000),
  valueFormatter = "#,###.",
  caption = amText(text = "Year 2018", color = "red"),
  theme = "material",
  elementId = "chartB"
)

# 添加延迟渲染逻辑
htmlwidgets::onRender(chart, '
function(el, x) {
  // 监听flexdashboard页面切换事件
  $(document).on("shown.bs.tab", function(e) {
    if ($(e.target).attr("href") === "#page-2") {
      if (!el._chartInitialized) {
        am4core.create(el, am4charts.XYChart);
        el._chartInitialized = true;
      }
    }
  });
  // 初始检查：如果当前页面是第二页，直接初始化
  if ($(".navbar-nav .active a").attr("href") === "#page-2") {
    el._chartInitialized = true;
  }
}
')

## 方案二：交互式仪表盘（启用Shiny）
如果允许使用Shiny runtime，通过动态渲染确保图表在页面激活时才生成DOM节点：

1. 修改YAML头部启用Shiny：
```r
---
title: "Untitled"
output: 
  flexdashboard::flex_dashboard:
    orientation: columns
    vertical_layout: fill
runtime: shiny
---

2. 修改第二页图表代码：

### Chart B

```{r}
uiOutput("chartB")

output$chartB <- renderUI({
  dat <- data.frame(
    country = c("USA", "China", "Japan", "Germany", "UK", "France"),
    visits = c(3025, 1882, 1809, 1322, 1122, 1114)
  )
  
  amBarChart(
    data = dat, data2 = dat,
    width = "600px",
    category = "country", values = "visits",
    draggable = TRUE,
    tooltip = "[bold font-style:italic #ffff00]{valueY.value.formatNumber('#,###.')}[/]",
    chartTitle = amText(text = "Visits per country", fontSize = 22, color = "orangered"),
    xAxis = list(title = amText(text = "Country", color = "maroon")),
    yAxis = list(
      title = amText(text = "Visits", color = "maroon"),
      gridLines = amLine(color = "orange", width = 1, opacity = 0.4)
    ),
    yLimits = c(0, 4000),
    valueFormatter = "#,###.",
    caption = amText(text = "Year 2018", color = "red"),
    theme = "material"
  )
})

# 注意事项
- 方案一适用于静态输出场景，无需额外依赖；方案二需要启用Shiny，适合交互式仪表盘。
- 确保`elementId`全局唯一，避免多个图表出现DOM节点冲突。

内容的提问来源于stack exchange，提问作者Stéphane Laurent