CODEWITHSUNDEEP
rshiny
john
john

Reputation: 1036

Overlapping two observeEvents

I have two overlapping observeEvents. By default dropdown value of test2 input id gets updated with 3 times of value in test1 inputid. If button is clicked, I want test1 to be updated with no. of clicks, accordingly dropdown value of test2 input id to be updated with 2 times (instead of 3) of value in test1 inputid.

Issue is as soon as test1 is triggered, it goes to observeEvent(input$test1, { }) and ignore update of test2 with 2 times.

Is there any way to tell shiny to ignore observeEvent(input$test1, { }) when btntest event is triggered.

ui <- fluidPage(
      

  # Application title
  titlePanel("Hello Shiny!"),
  
  fluidRow(
    column(width = 4,
      sliderInput("obs",
                  "Number of observations:",
                  min = 0,
                  max = 1000,
                  value = 500),
      
      selectizeInput("test1",
                     label = "Dropdown",
                     choices = 1:10),
      
      selectizeInput("test2",
                     label = "Dropdown2",
                     choices = NULL),
      
      actionButton("btntest", "Button1")
      
    )
    
)
)

# Server logic
server <- function(input, output, session) {
  
  observeEvent(input$test1, {
    updateSelectizeInput(session, "test2", 
                         choices = 3*as.numeric(input$test1))
  })
  
  myval <- reactiveValues()
  myval$count <- 0
  
  observeEvent(input$btntest, {
    
    myval$count <- myval$count + 1
    
    updateSelectizeInput(session, "test1", 
                         choices = 1:10,
                         selected = myval$count
    )
    
    updateSelectizeInput(session, "test2", 
                         choices = myval$count * 2
    )
    
  })
  
}

# Complete app with UI and server components
shinyApp(ui, server)

Upvotes: 1

Views: 80

Answers (1)

ismirsehregal
ismirsehregal

Reputation: 33407

You'll need to distinguish between updates triggered by the user and indirect updates. This can be done using a reactiveVal:

library(shiny)

ui <- fluidPage(titlePanel("Hello Shiny!"),
                fluidRow(
                  column(
                    width = 4,
                    sliderInput(
                      "obs",
                      "Number of observations:",
                      min = 0,
                      max = 1000,
                      value = 500
                    ),
                    selectizeInput("test1",
                                   label = "Dropdown",
                                   choices = 1:10),
                    
                    selectizeInput("test2",
                                   label = "Dropdown2",
                                   choices = NULL),
                    actionButton("btntest", "Button1")
                  )
                ))

server <- function(input, output, session) {
  
  indirectUpdate <- reactiveVal(FALSE)
  
  observeEvent(input$test1, {
    if(!indirectUpdate()){
      updateSelectizeInput(session, "test2",
                           choices = 3 * as.numeric(input$test1)) 
    }
    indirectUpdate(FALSE)
  })
  
  observeEvent(input$btntest, {
    indirectUpdate(TRUE)
    updateSelectizeInput(session,
                         "test1",
                         choices = 1:10,
                         selected = input$btntest)
    updateSelectizeInput(session, "test2",
                         choices = input$btntest * 2)
  })
}

shinyApp(ui, server)

Upvotes: 2

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