Unable to get flexdashboard modal Brilliant NULL responsiveness

Question

Firstly, here is a minimal reproducible example:

Suppose I have the following example.Rmdflexdashboard application :

---
title: "Test App"
output:
  flexdashboard::flex_dashboard:
    theme: ["lumen"]
    orientation: ["columns"]
runtime: shiny
---

```{r setup, include=FALSE}
source('modules.R')
```

Test
==================

Inputs {.sidebar data-width=250}
------------------

```{r}

## Modules:
globalInputs <- callModule(setup, "inputs")  # Note: you only need to call this one time!
callModule(chart, "modalChart", globalInputs)
## UI:
sidebar("inputs")

```

Column
-------------------------------------

### ModalTest

```{r}
chartUI2("modalChart")
```

Here is my modules.R file :

sidebar <- function(id) {
  ns <- NS(id)
  tagList(
    helpText("Press the button below to pull up a modal:"),
    actionButton(ns("settings"), "Settings", icon = icon("cogs"), width = '100%')
  )
}

# setup function
setup <- function(input, output, session) {
  return(input)  ## Note, input in this case is a reactive list of values that you can index against with $ or [[""]]
}

# UI module for the popup Settings modal
modalUI <- function(id) {
  ns <- NS(id)
  withTags({  # UI elements for the modal go in here
    ## Note: you can use the fluidPage() and fluidRow() functions to define a column-based UI for the chart inputs below:
    fluidPage(
      fluidRow(sliderInput(ns("bins"), "Number of bins:",
                           min = 1,  max = 50, value = 30),
               textInput(ns("plotTitle"), label = "Plot Title", value = "This is a test")
      ))
  })
}


## UI module for the 2 buttons in the modal:
modalFooterUI <- function(id) {
  ns <- NS(id)
  tagList(
    modalButton("Cancel", icon("remove")),
    actionButton(ns("modalApply"), "Apply", icon = icon("check"))
  )
}

## chart module ----------------------------------------------------------------
chartUI2 <- function(id) {
  ns <- NS(id)
  plotOutput(ns("distPlot"))
}

chart <- function(input, output, session, setup) {

  observeEvent(setup$settings, {
    showModal(modalDialog(
      modalUI("inputs"),  # Call UI function defined in './modules/modal.R'; note the namespace 'inputs' is the same globally for the app
      title = "Settings",
      footer = modalFooterUI("inputs"),
      size = "l",
      easyClose = TRUE,
      fade = TRUE)
    )
  })

  output$distPlot <- renderPlot({
    if (setup$settings == 0)
      return(
        hist(faithful[, 2],
             breaks = 5,  # if the button hasn't been pressed, default
             main = 'This is the default title',
             col = 'darkgray',
             border = 'white')
      )
    isolate({
      x <- faithful[, 2]
      bins <- setup$bins
      hist(x,
           breaks = bins,
           main = setup$plotTitle,
           col = 'darkgray',
           border = 'white')
    })

  })
}

Here I want to execute:

• When the page loads the rendering distPlotwith default options. This should always happen.
• When I click "Settings" actionButton, it issues a modal overlay (but keeps the chart in the background in its original state)
• Allow the user to change the parameters in the pop-up module, but do not redraw the graph until the user clicks the "Apply" button.

, # 1 , "", Invalid breakpoints produced by 'breaks(x)': NULL. , ( , actionButton (, , ).

?

!!

Answer 1

. , setup$settings 1, renderPlot . , , setup$bins - NULL, .

if renderPlot setup$bins , Apply :

output$distPlot <- renderPlot({
    if (setup$settings == 0 | !isTruthy(setup$modalApply)) {
        hist(faithful[, 2],
             breaks = 5,  # if the button hasn't been pressed, default
             main = 'This is the default title',
             col = 'darkgray',
             border = 'white')
      } else {
    isolate({
      x <- faithful[, 2]
      bins <- setup$bins
      hist(x,
           breaks = bins,
           main = setup$plotTitle,
           col = 'darkgray',
           border = 'white')
    })

!isTruthy TRUE, setup$modalApply is NULL ( ) 0 ( ). "", .

Edit:

, reactiveValues , . , "", , , :

 plot_params = reactiveValues(bins=5,title='This is the default title')


  output$distPlot <- renderPlot({
        hist(faithful[, 2],
             breaks = plot_params$bins,
             main = plot_params$title,
             col = 'darkgray',
             border = 'white')
  })

  observeEvent(setup$modalApply,{
    plot_params$bins = setup$bins
    plot_params$title = setup$plotTitle
  })