如何根據在反應式 function 中過濾的輸入在 Flexdashboard 中呈現 Leaflet 或 Plot？

Question

我正在構建一個 Flexdashboard，如果選擇了一個月，它應該呈現 plot，如果選擇“全部”，則應該呈現 Leaflet map。 我使用反應式 function 來過濾我的輸入 $month 並嘗試使用“If else”function，如下所示，但它不起作用。

---
title: "Demo Dashboard"
  #subtitle: "Dashboard still under development"
output: 
  flexdashboard::flex_dashboard:
    source_code: embed
    theme: lumen
    vertical_layout: fill
runtime: shiny
---


{r setup, include=FALSE}
library(flexdashboard)
library(htmlwidgets)
library(tidyverse)
library(plotly)
library(shiny)
library(scales)
library(leaflet)
library(sf)
library(st)


{r global, include=FALSE}
rr <- read.csv("reporting_rate.csv")
sf <- read_sf("Enugu_LGA/u_boundary_lgas.shp")

reporting_rate <- rr %>% 
select(LGA, Year, Month, Dataset, Reporting, Completeness, Timeliness, Rate)  

左連接 (sf) 中的 shapefile 返回“NA”，所以我改用右連接。 我對 R 和 Flexdashboard 比較陌生。 我還嘗試添加輸入控件並創建一個響應式 function 以根據輸入過濾我的數據。

reporting_rate <- sf %>%
  right_join(r_rate,
            by = c("lga_name" = "LGA")) 


Month <- unique(reporting_rate$Month)

shinyWidgets::prettyRadioButtons(
  inputId = "month",
  label = "Month",
  choices = c(Month, "All"),
  selected = "Dec")


slicer <- reactive({
  filter(reporting_rate, if(input$month == "All" ){Month == reporting_rate$Month}
         else{Month == input$month} 
})

如果從輸入中選擇“全部”，我現在希望呈現一個條形圖 plot，如果選擇了特定月份，則呈現一個 Leaflet map。

szn <- colorFactor(c("darkgreen", "orange", "navyblue"), 
                   c("Enugu North", "Enugu East", "Enugu West"))

if(slicer()$month == "All"){
  plotly::renderPlotly({
  p <- slicer() %>% 
    ggplot(aes(x = reorder(LGA, -Rate), y = Rate, fill = dataSet))+
    geom_col(stat = " identity", position = "dodge")+
    theme(legend.position = "bottom")

  plotly::ggplotly(p) %>% 
    layout(xaxis = list(
           title = 'LGA',
           tickangle=310))
})
}else
  {renderLeaflet({
    slicer() %>%
    leaflet() %>% 
    addPolygons(fillColor = ~szn(LGA),
              fillOpacity = 1,
              color = "white",
              weight = 1)

上面的代碼導致此錯誤消息“警告：錯誤 in.getReactiveEnvironment()$currentContext：沒有活動的反應上下文不允許操作。 • 你試圖做一些只能從反應消費者內部完成的事情。”

我不知道還能做什么。 請幫忙。

我曾嘗試使用if(input$month == "All")而不是if(slicer()$input == "All") ，如下所示，但它仍然無效。

if input$month == "All"){
  plotly::renderPlotly({
  p <- slicer() %>% 
    ggplot(aes(x = reorder(LGA, -Rate), y = Rate, fill = dataSet))+
    geom_col(stat = " identity", position = "dodge")+
    theme(legend.position = "bottom")

  plotly::ggplotly(p) %>% 
    layout(xaxis = list(
           title = 'LGA',
           tickangle=310))
})
}else
  {renderLeaflet({
    slicer() %>%
    leaflet() %>% 
    addPolygons(fillColor = ~szn(LGA),
              fillOpacity = 1,
              color = "white",
              weight = 1)

Answer 1

實現所需結果的一種選擇是使用由input$month觸發的observeEvent 。 除此之外，使用observeEvent有條件地呈現plotly圖表或leaflet map 需要一個額外的步驟，即我們必須通過 uiOutput 將圖表包裝在renderUI和uiOutput中：

這是使用一些簡單的假圖表的這種方法的最小可重現示例：

---
title: "Demo Dashboard"
output: 
  flexdashboard::flex_dashboard:
    source_code: embed
    theme: lumen
    vertical_layout: fill
runtime: shiny
---

```{r setup, include=FALSE}
library(flexdashboard)
library(tidyverse)
library(plotly)
library(shiny)
library(leaflet)
```

```{r}
shinyWidgets::prettyRadioButtons(
  inputId = "month",
  label = "Month",
  choices = c("Jan", "Dec", "All"),
  selected = "Dec"
)
```

```{r}
observeEvent(input$month, {
  if (!input$month == "All") {
    p <- ggplot(mtcars, aes(hp, mpg)) +
      geom_point()

    output$plot <- renderUI({
      renderPlotly({
        p
      })
    })
  } else {
    output$plot <- renderUI({
      renderLeaflet({
        leaflet() %>%
          addTiles() %>%
          addMarkers(lng = 174.768, lat = -36.852, popup = "The birthplace of R")
      })
    })
  }
})

uiOutput("plot")
```