R Shiny - 重置 renderText

Question

在以下代码中，目标是在单击 button1 后根据所选值重置 textoutput 的值：

library(shiny)
library(shinythemes)
library(DT, warn.conflicts = FALSE) #shiny also uses: dataTableOutput & renderDataTable
library(shinyjs)
library(shinyBS) #for tooltips on an input or output.
library(htmltools)

ui <- fluidPage(theme = shinytheme("lumen"),

                useShinyjs(),

                titlePanel(""),

                selectInput(
                  inputId = "test1",
                  label = strong("pick something"),
                  choices = c("a - button shows", "b - button hidden", "c - button hidden"),
                  selected = "b",
                  selectize = TRUE,
                  width = "175px",
                  multiple = FALSE),

                hidden(actionButton("button1", "Click Me")),

                htmlOutput(outputId = "textoutput")
)

server <- function(input, output, session) {

  output$textoutput <- renderText({

    if (input$test1 == "a - button shows"){
      print("a")
      shinyjs::show("button1")
      paste("<i><span style='color:blue'>You chose a. You should click the button.</span></i>")
    }

    else if (input$test1 == "b - button hidden"){
      print("b")
      shinyjs::hide("button1")
      paste("<i><span style='color:green'>You chose b. No button.</span></i>")
    }

    else {
      shinyjs::hide("button1")
      print("c")
      paste("<i><span style='color:orange'>The button is hidden.</span></i>")
    }

  })

  observeEvent(input$button1,{
    print(input$test1)
    output$textoutput <- renderText({ paste("<i><span style='color:purple'>You clicked the button.</span></i>")})
    shinyjs::hide("button1")
  })

}

# Create Shiny object
shinyApp(ui = ui, server = server)

运行代码按原样单击按钮，文本变为 You clicked the button.。我遇到问题的部分是当下拉列表的值更改为 "b" 或 "c"（单击按钮后）时，文本不会更改。我知道为什么它没有改变，但一直无法提出解决方案。

Answer 1

我想您会想要一个根据输入的各种变化进行更新的 output$textoutput。

也许 reactive 值可以包含您希望呈现的消息。例如：

server <- function(input, output, session) {

  msg_txt <- reactiveVal("")

  observe({
    if (input$test1 == "a - button shows"){
      print("a")
      shinyjs::show("button1")
      msg_txt("<i><span style='color:blue'>You chose a. You should click the button.</span></i>")
    }

    else if (input$test1 == "b - button hidden"){
      print("b")
      shinyjs::hide("button1")
      msg_txt("<i><span style='color:green'>You chose b. No button.</span></i>")
    }

    else {
      shinyjs::hide("button1")
      print("c")
      msg_txt("<i><span style='color:orange'>The button is hidden.</span></i>")
    }

  })

  output$textoutput <- renderText({ msg_txt() })

  observeEvent(input$button1,{
    print(input$test1)
    msg_txt("<i><span style='color:purple'>You clicked the button.</span></i>")
    shinyjs::hide("button1")
  })

}

这是否具有您正在寻找的行为？

R Shiny - 重置 renderText

R Shiny - Reset renderText

r

shiny

shinyjs