Rshiny App updatetextinput multiple times on one event - r

Question

I am trying to build a shiny app where with a click of a button 6 codes gets executed. since the processing time is 5-10 mins, to keep the users aware of the process, I want to have a textbox/verbatim box that will change basis which code is run.
"error in evaluating the argument 'x' in selecting a method for function 'head': object 'x' not found"
Edit : Have changed the code. However the first instance of text is not displayed "data loading".
TIA.
library(shinyjs)
library(shiny)
ui <- fluidPage(
titlePanel("Testing Textupdate Multiple Times"),
sidebarLayout(
sidebarPanel(
useShinyjs(),
actionButton("button1","Click"),
textInput("text1", label = "", value = ""),
dataTableOutput("table1")
),
mainPanel(
)
))
server = function(input, output,session) {
x<-data.frame()
observeEvent(input$button1, {
updateTextInput(session,"text1",value = "Data Loading")
withProgress(message = 'Data Loading',
detail = 'This may take a while...', value = 0, {
for (i in 1:10) {
incProgress(1/10)
Sys.sleep(0.25)
}
})
x<-mtcars
updateTextInput(session,"text1",value = "Data Loaded")})
output$table1 <- renderDataTable({
head(x)})
}
shinyApp(ui, server)

Answer 1

The updateTextInput will not be implemented until the end of the observeEvent, so the "Data Loading" message will not be seen. However, you can try a sendCustomMessage and add javascript to show the text instead. Here is a working example that uses verbatimTextOutput instead of a textInput. Please let me know if this works for you - I hope it is helpful.
library(shiny)
ui <- fluidPage(
tags$script('
Shiny.addCustomMessageHandler("status_text", function(text) {
document.getElementById("text1").innerHTML = text;
})
'),
titlePanel("Testing Textupdate Multiple Times"),
sidebarLayout(
sidebarPanel(
useShinyjs(),
actionButton("button1", "Click"),
verbatimTextOutput("text1")
),
mainPanel(
dataTableOutput("table1")
)
)
)
server = function(input, output, session) {
x <- mtcars
observeEvent(input$button1, {
session$sendCustomMessage("status_text", "Data loading...")
withProgress(message = 'Data Loading',
detail = 'This may take a while...', value = 0, {
for (i in 1:10) {
incProgress(1/10)
Sys.sleep(0.25)
}
})
session$sendCustomMessage("status_text", "Data loaded")
})
output$table1 <- renderDataTable({
head(x)
})
}
shinyApp(ui, server)
If you want the verbatimTextOutput to be present initially (but without text) you can add this to server:
output$text1 <- renderText({
" "
})