双击R-shiny

Question

I had a small questions. I have tried researching this a lot but I have had no luck. Is there a way R-shiny has to capture a double click on an element like a button.

Answer 1

Here is one way to do it. The key is to detect the dblclick event on the client side (ie ui), and then invoke Shiny.onInputChange to update the value of an R variable, which can then be picked up by the server.

Here is what happens when the button is double clicked.

1. The value is incremented by 1
2. The incremented value is used to update the variable x .
3. The server detects change in x
4. The server updates the textOutput .

 library(shiny) ui = bootstrapPage( tags$button(id = 'mybutton', 'button', class='btn btn-primary', value = 0), textOutput('x'), # when button is double clicked increase the value by one # and update the input variable x tags$script(" $('#mybutton').on('dblclick', function(){ var val = +this.value this.value = val + 1 Shiny.onInputChange('x', this.value) console.log(this.value) }) ") ) server = function(input, output, session){ output$x <- renderText({ input$x }) } runApp(list(ui = ui, server = server)) 

Answer 2

I've updated my answer based on the comment below. Here I used a threshold of time difference of 0.2 seconds to differentiate between a double clock and a regular click. I used slightly different approach in My App. I simply check how many times the button has been pressed by checking if its divisible by 2 or not.

library(shiny)
t1 <<- Sys.time()

ui =fluidPage(
  actionButton("my_button", "Dont Touch it!"),
  mainPanel(textOutput("x"))
)
server = function(input, output, session){
  my_data <- reactive({  
    if(input$my_button == 0)
    {
      return()
    }

    if(input$my_button%%2!=0)
    {     
      t1 <<- Sys.time()
    }  
    if(input$my_button%%2==0 & (Sys.time() - t1 <= 0.2))
    {     
      "You pushed the button twice!"
    }  
  }) 
  output$x <- renderText({my_data()})
}
runApp(list(ui = ui, server = server))