Ufdjrw

The header of my modalDialog is a reactiveValue. Once a certain input is changed within the modal, I would like the header to change. I have tried a few different ways and haven't been able to get it working seamlessly. The header either doesn't update, only updates if I close/reopen the modal, or causes the modal to re-render completely when the header is updated immediately.

Currently, I'm stuck on the last one (modal re-rendering completely). However, when I created the minimal, reproducible example (below), the header only updates if I close & reopen the modal.

ui<-fluidPage(
 actionButton(inputId="model", label="Edit Model")
)

server<-function(input, output, session) 
 rv<-reactiveValues(header="Standard Model")

 observeEvent(input$model, 
 showModal(
 modalDialog(
 fluidPage(
 fluidRow(h3(rv$header)),
 sliderInput(inputId="factor_1", "Factor #1", value=70, min=0, max=100),
 sliderInput(inputId="factor_2", "Factor #2", value=30, min=0, max=100)
 ),
 footer=modalButton("Save Weights"), size="s", easyClose=TRUE
 )
 )
 )

 observe(if (!is.null(input$factor_1)) 
 if (input$factor_1!=70) 
 rv$header<-"Custom Model"
 
 
 )


shinyApp(ui=ui, server=server)

Essentially, I want the title to change from 'Standard Model' to 'Custom Model' (without closing/reopening or re-rendering the modal) once the input for Factor #1 is changed for the first time.

Using renderUI/uiOutput:

library(shiny)

ui <- fluidPage(
 actionButton("model", label = "Edit Model") 
)

server <- function(input, output, session) 

 rv <- reactiveValues(header = "Standard Model")

 observeEvent(input[["model"]], 
 showModal(
 modalDialog(
 fluidPage(
 uiOutput("modalTitle"),
 sliderInput("factor_1", "Factor #1", value=70, min=0, max=100),
 sliderInput("factor_2", "Factor #2", value=30, min=0, max=100)
 ),
 footer = modalButton("Save Weights"), 
 size="s", easyClose=TRUE
 )
 )
 )

 output[["modalTitle"]] <- renderUI(
 fluidRow(h3(rv$header))
 )

 observe(
 if (!is.null(input$factor_1)) 
 if (input$factor_1 != 70) 
 rv$header <- "Custom Model"
 
 
 )



shinyApp(ui=ui, server=server)