I have an R6 class that I am using to organize my shiny application. Essentially, I want to connect different R6 classes for an experimental interface I am creating and want to reuse my code. As a simplified working example, see the code below.
library(R6)
library(stringi)
library(shiny)
df <- data.frame(dp = c("dp1", "dp2", "dp3"), desc = c("problem 1", "problem 2", "problem 3"))
app <- R6::R6Class(classname = "App",
private = list(
#unique string id
..id = stringi::stri_rand_strings(1, 18),
#the data to be iterated through
..df = df,
#counter to update text
..counter = 1,
#initiating the dp and desc
..dp = 'dp1',
..desc = 'problem 1',
#the underlying server, to be created like a normal server
.server = function(input, output, session){
output$text <- renderText({
private$..desc
})
observeEvent(input$button, {
private$..counter <- private$..counter 1
self$update_private()
#check the private content since the print is not updating
print(private$..counter)
print(private$..dp)
print(private$..desc)
})
}
),
public = list(
#create names for ui elements
button = NULL,
text = NULL,
initialize = function(){
self$button <- self$get_id("button")
self$text <- self$get_id("text")
self$update_private()
},
#gives ui outputs unique names tied to the user's id
get_id = function(name, ns = NS(NULL)){
ns <- NS(ns(private$..id))
id <- ns(name)
return(id)
},
#automatically updates the private field based on the counter
update_private = function(){
if(private$..counter == 1){
private$..dp <- "dp1"
} else if(private$..counter == 2){
private$..dp <- "dp2"
} else{
private$..dp <- "dp3"
}
private$..desc <- private$..df[private$..df$dp == private$..dp, "desc"]
},
ui = function(){
fluidPage(
h1("An Example"),
mainPanel(
textOutput(self$text)),
sidebarPanel(
shiny::actionButton(inputId = self$button,
label = 'Update!',
width = '100%'
))
)
},#end ui
server = function(input, output, session){
callModule(module = private$.server, id = private$..id)
}
)
)
test <- app$new()
ui <- test$ui()
server <- function(input, output, session) {
test$server()
}
shinyApp(ui = ui, server = server)
What I want: when someone clicks the action button, the reactive ui will update and the desired text from the data frame will be sliced and displayed. What I am getting: the internal private data fields are updating but the reactive ui elements are not.
Any ideas what could be causing this or a workaround? I thought about externally trying to use the observe event and then reinitiating the class with a new counter number. But I also can't seem to figure out that option either.
Appreciate your help!
CodePudding user response：
For anyone that comes across this problem... I figured out that even though the private is updating, and even though render is technically a reactive environment, you need to have your data stored publically in a reactive field.
library(R6)
library(stringi)
library(shiny)
df <- data.frame(dp = c("dp1", "dp2", "dp3"), desc = c("problem 1", "problem 2", "problem 3"))
app <- R6::R6Class(classname = "App",
private = list(
#unique string id
..id = stringi::stri_rand_strings(1, 18),
#the data to be iterated through
..df = df,
#counter to update text
..counter = 0,
#initiating the dp and desc
..dp = NA,
..desc = NA,
#the underlying server, to be created like a normal server
.server = function(input, output, session){
output$text <- renderText({
self$desc$text
})
observeEvent(input$button, {
private$..counter <- private$..counter 1
self$update_private()
self$desc$text <- private$..desc
#check the private content since the print is not updating
print(private$..counter)
print(private$..dp)
print(private$..desc)
})
}
),
active = list(
.counter = function(value){
if(missing(value)){
private$..counter
}else{
private$..counter <- value
}
}
),
public = list(
#create names for ui elements
button = NULL,
text = NULL,
#Need this to update the text***************
desc = reactiveValues(text = NA),
initialize = function(counter = self$.counter){
self$.counter <- counter
self$button <- self$get_id("button")
self$text <- self$get_id("text")
self$update_private()
self$desc$text <- private$..desc
},
#gives ui outputs unique names tied to the user's id
get_id = function(name, ns = NS(NULL)){
ns <- NS(ns(private$..id))
id <- ns(name)
return(id)
},
#automatically updates the private field based on the counter
update_private = function(){
if(private$..counter == 1){
private$..dp <- "dp1"
} else if(private$..counter == 2){
private$..dp <- "dp2"
} else{
private$..dp <- "dp3"
}
private$..desc <- private$..df[private$..df$dp == private$..dp, "desc"]
},
ui = function(){
fluidPage(
h1("An Example"),
mainPanel(
textOutput(self$text)),
sidebarPanel(
shiny::actionButton(inputId = self$button,
label = 'Update!',
width = '100%'
))
)
},#end ui
server = function(input, output, session){
counter <- reactiveVal(private$..counter)
callModule(module = private$.server, id = private$..id)
}
)
)
test <- app$new(counter = 1)
ui <- test$ui()
server <- function(input, output, session) {
test$server()
}
shinyApp(ui = ui, server = server)