Disabling fileInput

Question

I have one selectizeInput and one fileInput in my shiny app.

I want to keep fileInput disabled until some value is not selected in selectizeInput.

Also I want a popup message to select a value every time user clicks on fileInput. How can I do that.

Answer 1

As others have mentioned, the shinyjs package is useful here. You could use enable, disable, or toggleState.

library(shiny)
library(shinyjs)

ui = fluidPage(
    shinyjs::useShinyjs(),
    selectizeInput("selector", label="Choose 2:", multiple=TRUE,
                   choices=letters[1:5], selected=letters[1:5]),
    fileInput("file_inputer", label="upload file")#,
    # dataTableOutput('table') 
)

server = function(input, output) {
    observe({
        shinyjs::toggleState("file_inputer", length(input$selector) %in% 0:4)
    })

    observeEvent(input$file_inputer, {
        showModal(modalDialog(
           title="Do you want a header row?",
           selectInput("option_selector", label="Choose an option",
                       choices=c("option 1", "option 2", "option 3")),
           footer = tagList(actionButton("read_file", "Read File"),
                            modalButton("Cancel")
           )
        ))
    })

    observeEvent(input$read_file, {
        # do something with your option value
        removeModal()
    })

}

# Run the application 
shinyApp(ui = ui, server = server)