相关输入的闪亮优先级

Question

考虑使用三个输入的这个应用程序，所有这些应用程序彼此相关...

library(tidyverse)
library(shiny)
df <- mtcars %>% 
  split(.$vs)


ui <- fluidPage(
  sidebarPanel(
    radioButtons("no1", "Select", choices = names(df)),
    selectInput("no2", "select", choices = NULL),
    selectInput("no3", "select", choices = NULL)
  ),
  mainPanel(plotOutput("plot"))
)

server <- function(input, output, session){
  
 rv <- reactiveValues()  
 
 observe({
   req(input$no1)
   updateSelectInput(session,"no2", choices = df[[input$no1]]$cyl)
 }, priority = 10)
  
 observe({
   rv$after_v1_v2 <- df[[input$no1]] %>% filter(cyl == input$no2)
 }, priority = 9)
   
   
  observe({
    req(input$no1)
    req(input$no2)
    updateSelectInput(session,"no3", choices = rv$after_v1_v2$am )
  }, priority = 8)
  
  observe({
    rv$after_v3 <- rv$after_v1_v2 %>% filter(am == input$no3)
  }, priority = 7)
  
  
  output$plot <- renderPlot({
    Sys.sleep(2)
    rv$after_v3 %>% 
      ggplot(aes(disp, hp)) + 
       geom_point()
  })
  
  outputOptions(output, "plot", priority = 1)
}

shiny::shinyApp(ui, server)

...我如何防止在更新侧面输入之前呈现图。如您所见，优先参数无效。更新应依次独立进行哪些输入更改，例如No1＆gt;＆gt; no2＆gt;＆gt; NO3，然后最后是情节。

我知道有一个debounce（），但我不想“手动”放慢应用程序。

Answer 1

使用FreezereActiveValue找到了解决方案。

library(tidyverse)
library(shiny)
df <- mtcars %>% 
  split(.$vs)


ui <- fluidPage(
  sidebarPanel(
    radioButtons("no1", "Select", choices = names(df)),
    selectInput("no2", "select", choices = NULL),
    selectInput("no3", "select", choices = NULL)
  ),
  mainPanel(plotOutput("plot"))
)

server <- function(input, output, session){
  
 rv <- reactiveValues()  
 
 observe({
   updateSelectInput(session,"no2", choices = df[[input$no1]]$cyl)
   freezeReactiveValue(input, "no3")
 }, priority = 10)
  
   
  observe({
    rv$after_v1_v2 <- df[[input$no1]] %>% filter(cyl == input$no2)
    updateSelectInput(session,"no3", choices = rv$after_v1_v2$am )
    freezeReactiveValue(input, "no3")
  }, priority = 8)
  
  observe({
    req(input$no3)
    rv$after_v3 <- rv$after_v1_v2 %>% filter(am == input$no3)
  }, priority = 7)
  
  
  output$plot <- renderPlot({
    req(input$no1)
    req(input$no2)
    req(input$no3)
    Sys.sleep(2)
    rv$after_v3 %>% 
      ggplot(aes(disp, hp)) + 
       geom_point()
  })
  
  outputOptions(output, "plot", priority = 1)
}

shiny::shinyApp(ui, server)