问题
I have multiple action buttons, on which i want to show different select Inputs and I want to know last clicked button id, how can I do that? When I use
which(lapply(c(1:10), function(i) { input[[paste0("ActionButton", i)]]}) == TRUE)
It shows me all button which were clicked, however I want to know which one was the last in order to enable click once again on previous buttons. How can I do that? I am new in shiny and not sure if understand all reactive/isolate issue so I would be greateful for any hints.
回答1:
You can do it by adding JS
smthing like
$(document).on('click', '.needed', function () {
Shiny.onInputChange('last_btn',this.id);
});
Example ( add class needed
to btn if you want to control not all btn)
ui <- shinyUI(fluidPage(
titlePanel("Track last clicked Action button"),
tags$head(tags$script(HTML("$(document).on('click', '.needed', function () {
Shiny.onInputChange('last_btn',this.id);
});"))),
sidebarLayout(
sidebarPanel(
actionButton("first", "First",class="needed"),
actionButton("second", "Second",class="needed"),
actionButton("third", "Third",class="needed"),
actionButton("save", "save"),
selectInput("which_","which_",c("first","second","third"))
),
mainPanel(
textOutput("lastButtonCliked")
)
)
))
server <- shinyServer(function(input, output,session) {
observeEvent(input$save,{
updateSelectInput(session,"which_",selected = input$last_btn)
})
output$lastButtonCliked=renderText({input$last_btn})
})
# Run the application
shinyApp(ui = ui, server = server)
回答2:
This code track which button was last clicked:
library(shiny)
ui <- shinyUI(fluidPage(
titlePanel("Track last clicked Action button"),
sidebarLayout(
sidebarPanel(
actionButton("first", "First"),
actionButton("second", "Second"),
actionButton("third", "Third")
),
# Show a plot of the generated distribution
mainPanel(
textOutput("lastButtonCliked")
)
)
))
server <- shinyServer(function(input, output) {
rv <- reactiveValues(lastBtn = character())
observeEvent(input$first, {
if (input$first > 0 ) {
rv$lastBtn = "first"
}
})
observeEvent(input$second, {
if (input$second > 0 ) {
rv$lastBtn = "second"
}
})
observeEvent(input$third, {
if (input$third > 0 ) {
rv$lastBtn = "third"
}
})
output$lastButtonCliked <- renderText({
paste("Last button clicked: ", rv$lastBtn)
})
})
# Run the application
shinyApp(ui = ui, server = server)
Version with lapply with many buttons. Credit goes to @Victorp and this answer.
This is the code:
library("shiny")
ui <- fluidPage(
fluidRow(
column(
width = 6,
lapply(
X = 1:5,
FUN = function(i) {
actionButton(inputId = paste0("button", i), label = paste("Button ", i))
}
)
),
column(
width = 6,
textOutput("lastButtonCliked")
)
)
)
server <- function(input, output){
rv <- reactiveValues(lastBtn = character())
lapply(
X = 1:6,
FUN = function(i){
observeEvent(input[[paste0("button", i)]], {
if (input[[paste0("button", i)]] > 0) {
rv$lastBtn = paste0("button", i)
}
})
}
)
output$lastButtonCliked <- renderText({
paste("Last button clicked: ", rv$lastBtn)
})
}
shinyApp(ui = ui, server = server)
来源:https://stackoverflow.com/questions/40168801/r-shiny-last-clicked-button-id