I have a code that takes inputs using the readlines(prompt = ) function. Could you tell me which input function in Shiny will be adequate to adapt this code to a Shiny app?
I need an interactive function, I can't use a simple input with selectInput() because I have a lot of readlines(prompt = ) statements.
Something similar to this question:
Include interactive function in shiny to highlight "readlines" and "print"
Florian's answer is nice and easy to use, I would definitely recommend that! But in case you are keen on using prompts for inputs I am adding another solution, using javaScript:
This one shows a prompt when the user presses an actionButton and stores it in an input variable. (it doesn't necessarily have to be after a button press)
library(shiny)
ui <- fluidPage(
tags$head(tags$script("
$(document).on('shiny:inputchanged', function(event) {
if (event.name === 'go') {
var text = prompt('Write me something nice:');
Shiny.onInputChange('mytext', text);
}
});"
)),
actionButton("go", "Click for prompt"),
textOutput("txt")
)
server <- function(input, output, session) {
output$txt <- renderText( {
input$mytext
})
}
shinyApp(ui, server)
Maybe you could use textArea for this purpose. Working example below, hope this helps!
library(shiny)
ui <- fluidPage(
tags$textarea(id="text", rows=4, cols=40),
htmlOutput('val')
)
server <- function(input,output)
{
output$val <- renderText({
text = gsub('\n','<br>',input$text)
text
})
}
shinyApp(ui,server)
Related
There are numerous posts regarding changing titles of other pieces of Shiny apps, e.g.:
Change the title by pressing a shiny button Shiny R
Shiny page title and image
Shiny App: How to dynamically change box title in server.R?
My question is related, but not answered by any of these. I would like to make the <head><title>...</title></head> tag reactive, or at least controllable from within an observeEvent in server.R.
The following does not work, since ui can't find theTitle, but is the kind of approach I'd hope is possible:
library(shiny)
ui <- fluidPage(
title = theTitle(),
textInput("pageTitle", "Enter text:")
)
server <- function(input, output, session) {
theTitle <- reactiveVal()
observeEvent( input$pageTitle, {
if(is.null(input$pageTitle)) {
theTitle("No title yet.")
} else {
theTitle(input$pageTitle)
}
})
}
I've tried making output$theTitle <- renderText({...}) with the if..else logic in that observeEvent, and then setting title = textOutput("theTitle") in ui's fluidPage, but that generates <div ...> as the title text, or <span ...> if we pass inline=True to renderText.
In case this clarifies what I'm looking for, the answer would make something equivalent to the literal (replacing string variables with that string) ui generated by
ui <- fluidPage(
title = "No title yet.",
....
)
before the user has entered any text in the box; if they have entered "Shiny is great!" into input$pageTitle's box, then we would get the literal
ui <- fluidPage(
title = "Shiny is great!",
....
)
One way would be to write some javascript to take care of that. For example
ui <- fluidPage(
title = "No title yet.",
textInput("pageTitle", "Enter text:"),
tags$script(HTML('Shiny.addCustomMessageHandler("changetitle", function(x) {document.title=x});'))
)
server <- function(input, output, session) {
observeEvent( input$pageTitle, {
title <- if(!is.null(input$pageTitle) && nchar(input$pageTitle)>0) {
input$pageTitle
} else {
"No title yet."
}
session$sendCustomMessage("changetitle", title)
})
}
shinyApp(ui, server)
This was created following the How to send messages from the browser to the server and back using Shiny guide
As of June 2021, there is an R package called shinytitle that can update the window title from within Shiny's reactive context: https://cran.r-project.org/package=shinytitle
I am trying to do something which I thought would be relatively simple, but I cannot seem to figure it out.
I am attempting to have an actionLink which, when pressed, provides additional information for the user. When pressed again it hides the information. I can do this fine, but what I am struggling with is updating the text of the actionLink.
I want it to read "Show additional" when the extra information is hidden, and then "Hide additional" when the information is exposed. I have read the following questions/answers, but cannot quite get it to work.
Modify shiny action button once it is clicked
Update label of actionButton in shiny
I have provided a simple code for this below, though the real example will be a lot more complex.
Thank you for your time and help.
shinyApp(
ui = shinyUI(fluidPage(useShinyjs(),
actionLink("button", "Show additional"),
hidden(
div(id='text_div',
verbatimTextOutput("text")
)
)
)
),
server = function(input, output, session){
observeEvent(input$button, {
toggle('text_div')
output$text <- renderText({"Additional"})
})
}
)
You can check for the value of input$button(which increments by 1 each time you click on it) and update the actionLink label parameter in function of its value with updateActionButton :
shinyApp(
ui = shinyUI(
fluidPage(useShinyjs(),
actionLink("button", "Show additional"),
hidden(div(id='text_div', verbatimTextOutput("text")))
)
),
server = function(input, output, session){
observeEvent(input$button, {
toggle('text_div')
output$text <- renderText({"Additional"})
if (input$button %% 2 == 1) {
txt <- "Hide Additional"
} else {
txt <- "Show Additional"
}
updateActionButton(session, "button", label = txt)
})
}
)
I am writing some Shiny code where the user will enter some inputs to the app and then click a an action button. The action button triggers a bunch of simulations to run that take a long time so I want once the action button is clicked for it to be disabled so that the user can't keep clicking it until the simulations are run. I came across the shinyjs::enable and shinyjs::disable functions but have been having a hard time utilizing them. Here is my server code:
output$button1= renderUI({
if(input$Button1 > 0) {
shinyjs::disable("Button1")
tableOutput("table")
shinyjs::enable("Button1")}
})
However, when I use this code, and click the action button nothing happens. I.e., teh action button doesn't grey out nor does the table get generated. However, when I take away the shinyjs::enable() command, i.e.,
output$button1= renderUI({
if(input$Button1 > 0) {
shinyjs::disable("Button1")
tableOutput("table")
}
})
The table gets generated first, and then the button goes grey, however I would have expected the button to go grey and then the table to generate itself.
What am I doing wrong here?
Here is my updated code based on Geovany's suggestion yet it still doesn't work for me
Button1Ready <- reactiveValues(ok = FALSE)
observeEvent(input$Button1, {
shinyjs::disable("Button1")
RunButton1Ready$ok <- FALSE
RunButton1Ready$ok <- TRUE
})
output$SumUI1= renderUI({
if(Button1Ready$ok){
tableOutput("table")
shinyjs::enable("Button1")
}
})
where for clarification I have also:
output$table <- renderTable({
#My code....
)}
I think that you are using shinyjs::disable and shinyjs::enable in the same reactive function. You will only see the last effect. I will recommend you to split in different reactive functions the disable/enable and use an extra reactive variable to control the reactivation of the button.
I don't know how exactly your code is, but in the code below the main idea is illustrated.
library(shiny)
library(shinyjs)
ui <- fluidPage(
shinyjs::useShinyjs(),
sidebarLayout(
sidebarPanel(
actionButton("Button1", "Run"),
shinyjs::hidden(p(id = "text1", "Processing..."))
),
mainPanel(
plotOutput("plot")
)
)
)
server <- function(input, output) {
plotReady <- reactiveValues(ok = FALSE)
observeEvent(input$Button1, {
shinyjs::disable("Button1")
shinyjs::show("text1")
plotReady$ok <- FALSE
# do some cool and complex stuff
Sys.sleep(2)
plotReady$ok <- TRUE
})
output$plot <-renderPlot({
if (plotReady$ok) {
shinyjs::enable("Button1")
shinyjs::hide("text1")
hist(rnorm(100, 4, 1),breaks = 50)
}
})
}
shinyApp(ui, server)
I intended to have some optional extra buttons appearing in my shiny app using renderUI. I would prefer to have new buttons inserted in the one and same renderUI call. I wrote a renderUI expession were the second button only is rendered if input of fist button is not null and(&&) is TRUE. It does not work as first button rapidly unchecks itself again whenever checked. I made a solution by splitting into two renderUI calls.
My question are:
Why exactly does the first code piece fail?
Would it be possible to achieve what the second code piece does in only one renderUI call?
.
library(shiny)
ui = fluidPage(
uiOutput("checkUI")
)
server = function(input,output) {
output$checkUI = renderUI({
list(
checkboxInput('check1',"check me first"),
if(!is.null(input$check1)&&input$check1==T) {
checkboxInput('check2',"check me to win")
} else {
NULL
}
)
})
}
shinyApp(ui,server)
but this works...
ui = fluidPage(
uiOutput("checkUI"),
uiOutput("textUI")
)
server = function(input,output) {
#UI first button
output$checkUI = renderUI({
list(
checkboxInput('check1',"check me first")
)
})
#UI second button
output$textUI = renderUI({
list(
if(!is.null(input$check1) && input$check1)
checkboxInput('check2',"check me to win") else NULL
)
})
}
shinyApp(ui,server)
Your first piece of code fails because the renderUI runs every time there is a change in input, so when you check the first check box. Since you have:
checkboxInput('check1',"check me first")
The renderUI immediately resets the input$check1 and then the renderUI is run again, unsetting the checkbox. This is why the second checkbox briefly flashes.
Luckily this is a common problem, so there is a Shiny solution to this with conditionalPanels:
library(shiny)
ui = fluidPage(
checkboxInput('check1',"check me first"),
conditionalPanel(
condition = "input.check1 == true",
checkboxInput("check2", "check me to win")
)
)
server = function(input,output){
}
shinyApp(ui,server)
I created a table containing some HTML links using Shiny's renderDataTable. The links are not clickable, though, instead they render literally:
https://samizdat.shinyapps.io/zakazky/
Do you have any idea what could be wrong? It worked fine before upgrading Shiny to the version 0.11... Thanks!
I had the same problem. The escape = FALSE option for renderDataTable solved it, as you mentioned in the comments.
Here is complete code for an app with a table that has links.
If you are doing this, you will want each link to be unique based on a value in the table. I move this code into a function so its cleaner.
#app.R#
library(shiny)
createLink <- function(val) {
sprintf('Info',val)
}
ui <- fluidPage(
titlePanel("Table with Links!"),
sidebarLayout(
sidebarPanel(
h4("Click the link in the table to see
a google search for the car.")
),
mainPanel(
dataTableOutput('table1')
)
)
)
server <- function(input, output) {
output$table1 <- renderDataTable({
my_table <- cbind(rownames(mtcars), mtcars)
colnames(my_table)[1] <- 'car'
my_table$link <- createLink(my_table$car)
return(my_table)
}, escape = FALSE)
}
shinyApp(ui, server)