CODEWITHSUNDEEP
rshinyreactive-programming
Kira Tebbe
Kira Tebbe

Reputation: 586

Shiny: add button label to sidebar & update buttons after click

I'm a bit rusty to Shiny reactivity, but I want to do two things when a button is clicked:

  1. add that button label to the sidebar (and add more labels to sidebar after more clicks)
  2. update the button labels (i.e. more random integers)

I'm nervous about changing the label before recording it, so I want to get the timing right. Here's a skeleton of what I'm working with:

library(shiny)

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel( 
      textOutput("clicks")
    ),
    mainPanel(
      uiOutput("button1"), 
      uiOutput("button2")
    ))
)
###################
server <- function(input, output, session) {

  output$clicks <- renderText({
    paste()
  })

  ## reactive values
  inside <- reactive({
    inside <- sample(1:100,2)
  })

  ## buttons
  output$button1 <- renderUI({
    actionButton("course1", label = inside()[1], style='padding:50px')
  })
  output$button2 <- renderUI({
    actionButton("course2", label = inside()[2], style='padding:50px')
  })
}

shinyApp(ui = ui, server = server)

Right now the sidebar is blank because I'm not sure how to add it, or what to add to make the button labels update after a click (whether to do it inside a reactive value or an observeEvent). Any help is much appreciated!

Upvotes: 0

Views: 841

Answers (1)

Shape
Shape

Reputation: 2952

Here's a way to do it with reactiveValues:

library(shiny)

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel( 
      textOutput("clicks")
    ),
    mainPanel(
      uiOutput("button1"), 
      uiOutput("button2")
    ))
)
###################
server <- function(input, output, session) {
  # Show history
  output$clicks <- renderText({
    history[['clicked']]
  })

  ## reactive values
  # store history as reactive values
  history <- reactiveValues(clicked = c())
  # update history when a button is clicked
  observeEvent(input$course1,{
    history[['clicked']] <- c(history[['clicked']],inside()[1])
  })

  observeEvent(input$course2,{
    history[['clicked']] <- c(history[['clicked']],inside()[2])
  })
  #update inside when history updates
  inside <- reactive({
    history[['clicked']]
    inside <- sample(1:100,2)
  })

  ## buttons
  output$button1 <- renderUI({
    actionButton("course1", label = inside()[1], style='padding:50px')
  })
  output$button2 <- renderUI({
    actionButton("course2", label = inside()[2], style='padding:50px')
  })
}

shinyApp(ui = ui, server = server)

Upvotes: 2

Related Questions