Good days, I am programming in Rstudio, using shiny, and I wanted to generate an alert that is activated only when I want to leave a tabPanel without completing a condition, but not if I do not enter the tabPanel before, this is the way I found. The problem is that every time that I leave the Panel 1 without fulfilling the condition of completing text, alerts are generated that are accumulating (1 alert the first time, two the second, three the third, etc.) I wanted to consult if somebody knows why it is this and how to avoid it.
thank you very much
library(shiny)
library(ggplot2)
library(shinyalert)
ui <- fluidPage(
tabsetPanel(
id = "tabselected",
tabPanel("Tab2",""),
tabPanel("Tab1", textInput("requiredText", "Required Text"))
))
server <- function(input, output, session) {
observe({
req(input$tabselected == "Tab1")
observeEvent(
input$tabselected,
if (input$tabselected != "Tab1" & !isTruthy(input$requiredText)) {
shinyalert(title = "Save your work before changing tab",
type = "warning",
showConfirmButton = TRUE
)
updateTabsetPanel(session, inputId = "tabselected", selected = "Tab1")
}
)
}
)
}
shinyApp(ui = ui, server = server)
Is this the behavior you desire? Your example was recursive so you had reoccurring popup event. We can create a reactiveValues variable to keep track of the events, like so:
library(shiny)
library(ggplot2)
library(shinyalert)
ui <- fluidPage(
tabsetPanel(
id = "tabselected",
tabPanel("Tab2",""),
tabPanel("Tab1", textInput("requiredText", "Required Text"))
))
server <- function(input, output, session) {
v <- reactiveValues(to_alert = FALSE)
observeEvent(input$tabselected,{
if (input$tabselected != "Tab1" & !isTruthy(input$requiredText)) {
v$to_alert <- TRUE
}else{
v$to_alert <- FALSE
}
},ignoreInit = TRUE)
observeEvent(v$to_alert,{
if (v$to_alert){
shinyalert(title = "Save your work before changing tab", type = "warning",showConfirmButton = TRUE)
updateTabsetPanel(session, inputId = "tabselected", selected = "Tab1")
}
})
}
shinyApp(ui = ui, server = server)
I've created a SelectizeInput() UI using the insertUI() function. Essentially, I have an action button which adds a SelectizeInput() every time it's clicked. The idea is that the user selects columns from their data to put into groups. The creation of the UI works fine. I can also see in the Shiny trace that the selection works fine. However, I'm unsure how to access these variables to use in later plots. This is the code I have:
UI:
actionButton("cr_exp", "Create new biological group")
Server:
observeEvent(input$cr_exp, {
insertUI(
selector = "#cr_exp",
where = "afterEnd",
ui = selectizeInput(inputId = paste0("grp", input$cr_exp), label = "Select samples", choices = colnames(exp_dff()), options = list(create=TRUE), multiple=TRUE))
tags$div(id = paste0("grp", input$cr_exp))
})
In the shiny trace, it shows that the group is created, but I can't figure out how to access the value:
RECV {"method":"update","data":{"grp1":["MV4negControl01","MV4negControl02"]}}
You access the values just like any other input values: by the input element’s
id from the input reactive values:
library(shiny)
ui <- fluidPage(
actionButton("cr_exp", "Create new biological group"),
verbatimTextOutput("choices")
)
server <- function(input, output, session) {
observeEvent(input$cr_exp, {
insertUI(
selector = "#cr_exp",
where = "afterEnd",
ui = selectizeInput(
inputId = paste0("grp", input$cr_exp),
label = "Select samples",
choices = LETTERS,
options = list(create = TRUE),
multiple = TRUE
)
)
tags$div(id = paste0("grp", input$cr_exp))
})
output$choices <- renderPrint({
lapply(seq_len(input$cr_exp), function(i) input[[paste0("grp", i)]])
})
}
shinyApp(ui, server)
I have the following app which allows for text to be entered and it is then saved as VALUE and printed on a panel.
Although it looks like I can only do this with one text input at a time - even if I click add (so I don't believe this button is working). On top of that I would like for the user to be able to add multiple inputs (like I have below).
And then my VALUE function should be list with multiple inputs.
code below
library(shiny)
ui <- fluidPage(
headerPanel("R Package App"),
sidebarPanel(
# selectInput("options", "options", choices=c('abc','def')),
textInput("textbox", "Enter R Package Name", ""),
actionButton("add","Add")
),
mainPanel(
textOutput("caption")
)
)
server <- function(input, output, session) {
observe({
VALUE <- ''
if(input$add>0) {
isolate({
VALUE <- input$textbox
})
}
updateTextInput(session, inputId = "textbox", value = VALUE)
})
output$caption <- renderText({
input$textbox
})
}
shinyApp(ui = ui, server = server)
Have you considered using selectizeInput with it's create option?
library(shiny)
packagesDF <- as.data.frame(installed.packages())
ui <- fluidPage(
headerPanel("R Package App"),
sidebarPanel(
selectizeInput(
inputId = "selectedPackages",
label = "Enter R Package Name",
choices = packagesDF$Package,
selected = NULL,
multiple = TRUE,
width = "100%",
options = list(
'plugins' = list('remove_button'),
'create' = TRUE,
'persist' = TRUE
)
)
),
mainPanel(textOutput("caption"))
)
server <- function(input, output, session) {
output$caption <- renderText({
paste0(input$selectedPackages, collapse = ", ")
})
}
shinyApp(ui = ui, server = server)
I have a checkboxGroupInput in my shiny app. It seems that the multiple selection is always enabled. What I need is to disable the multiple selection and only allow one selection at a time.
Does anyone know how to do that? Shiny app example below:
ui <- fluidPage(
checkboxGroupInput("icons", "Choose icons:",
choiceNames =
list(icon("calendar"), icon("bed"),
icon("cog"), icon("bug")),
choiceValues =
list("calendar", "bed", "cog", "bug")
),
textOutput("txt")
)
server <- function(input, output, session) {
output$txt <- renderText({
icons <- paste(input$icons, collapse = ", ")
paste("You chose", icons)
})
}
shinyApp(ui, server)
Here is the checkboxGroupInput function. I'm surprised there is no argument like multiple. Should I use other widget to serve that purpose? What should I use?
checkboxGroupInput(inputId, label, choices = NULL, selected = NULL,
inline = FALSE, width = NULL, choiceNames = NULL,
choiceValues = NULL)
I would like to implement a 'Reset inputs' button in my shiny app.
Here is an example with just two inputs where I'm using the update functions to set the values back to the default values:
library(shiny)
runApp(list(
ui = pageWithSidebar(
headerPanel("'Reset inputs' button example"),
sidebarPanel(
numericInput("mynumber", "Enter a number", 20),
textInput("mytext", "Enter a text", "test"),
tags$hr(),
actionButton("reset_input", "Reset inputs")
),
mainPanel(
h4("Summary"),
verbatimTextOutput("summary")
)
),
server = function(input, output, session) {
output$summary <- renderText({
return(paste(input$mytext, input$mynumber))
})
observe({
input$reset_input
updateNumericInput(session, "mynumber", value = 20)
updateTextInput(session, "mytext", value = "test")
})
}
))
What I would like to know is if there is also a function that sets back everything to default? That would be useful in case of multiple inputs.
Additionally, I'm not sure if my use of the observe function in order to detect when the action button was hit is the 'proper way' of handling the action buttons?
First of all, your use of the observer is correct, but there is another way that's slightly nicer. Instead of
observe({
input$reset_input
updateNumericInput(session, "mynumber", value = 20)
updateTextInput(session, "mytext", value = "test")
})
You can change it to
observeEvent(input$reset_input, {
updateNumericInput(session, "mynumber", value = 20)
updateTextInput(session, "mytext", value = "test")
})
Also note that you don't need to explicitly "return" from a renderText function, the last statement will automatically be used.
Regarding the main question: Matthew's solution is great, but there's also a way to achieve what you want without having to move all your UI into the server. I think it's better practice to keep your UI in the UI file just because separation of structure and logic is generally a good idea.
Full disclaimer: my solution involves using a package that I wrote. My package shinyjs has a reset function that allows you to reset an input or an HTML section back to its original value. Here is how to tweak your original code to your desired behaviour in a way that will scale to any number of inputs without having to add any code. All I had to do is add a call to useShinyjs() in the UI, add an "id" attribute to the form, and call reset(id) on the form.
library(shiny)
runApp(list(
ui = pageWithSidebar(
headerPanel("'Reset inputs' button example"),
sidebarPanel(
shinyjs::useShinyjs(),
id = "side-panel",
numericInput("mynumber", "Enter a number", 20),
textInput("mytext", "Enter a text", "test"),
tags$hr(),
actionButton("reset_input", "Reset inputs")
),
mainPanel(
h4("Summary"),
verbatimTextOutput("summary")
)
),
server = function(input, output, session) {
output$summary <- renderText({
return(paste(input$mytext, input$mynumber))
})
observeEvent(input$reset_input, {
shinyjs::reset("side-panel")
})
}
))
There isn't such a function in shiny, however, here's a way to accomplish this without having to essentially define your inputs twice. The trick is to use uiOutput and wrap the inputs you want to reset in a div whose id changes to something new each time the reset button is pressed.
library(shiny)
runApp(list(
ui = pageWithSidebar(
headerPanel("'Reset inputs' button example"),
sidebarPanel(
uiOutput('resetable_input'),
tags$hr(),
actionButton("reset_input", "Reset inputs")
),
mainPanel(
h4("Summary"),
verbatimTextOutput("summary")
)
),
server = function(input, output, session) {
output$summary <- renderText({
return(paste(input$mytext, input$mynumber))
})
output$resetable_input <- renderUI({
times <- input$reset_input
div(id=letters[(times %% length(letters)) + 1],
numericInput("mynumber", "Enter a number", 20),
textInput("mytext", "Enter a text", "test"))
})
}
))
Here is yet another option that works for either static or dynamic inputs, and doesn't involve re-rendering inputs entirely.
It uses:
reactiveValuesToList to get all initial input values, and (optionally) any dynamic input values that get initialized afterward.
session$sendInputMessage to update values for generic inputs. The updateXyzInput functions call this under the hood like session$sendInputMessage(inputId, list(value = x, ...).
Every Shiny input uses value for its input message, and almost all will update with their input value as-is. Only a two inputs I've found need special casing - checkboxGroupInput to not send NULL when nothing is checked, and dateRangeInput to convert its c(start, end) to a list(start = start, end = end).
It may not be a good idea to blindly reset ALL inputs (even tabs will be reset), but this can easily be adapted to reset a filtered set of inputs.
library(shiny)
ui <- pageWithSidebar(
headerPanel("'Reset inputs' button example"),
sidebarPanel(
numericInput("mynumber", "Enter a number", 20),
textInput("mytext", "Enter text", "test"),
textAreaInput("mytextarea", "Enter text", "test"),
passwordInput("mypassword", "Enter a password", "password"),
checkboxInput("mycheckbox", "Check"),
checkboxGroupInput("mycheckboxgroup", "Choose a number", choices = c(1, 2, 3)),
radioButtons("myradio", "Select a number", c(1, 2, 3)),
sliderInput("myslider", "Select a number", 1, 5, c(1,2)),
uiOutput("myselUI"),
uiOutput("mydateUI"),
tags$hr(),
actionButton("reset_input", "Reset inputs")
),
mainPanel(
h4("Summary"),
verbatimTextOutput("summary")
)
)
server <- function(input, output, session) {
initialInputs <- isolate(reactiveValuesToList(input))
observe({
# OPTIONAL - save initial values of dynamic inputs
inputValues <- reactiveValuesToList(input)
initialInputs <<- utils::modifyList(inputValues, initialInputs)
})
observeEvent(input$reset_input, {
for (id in names(initialInputs)) {
value <- initialInputs[[id]]
# For empty checkboxGroupInputs
if (is.null(value)) value <- ""
session$sendInputMessage(id, list(value = value))
}
})
output$myselUI <- renderUI({
selectInput("mysel", "Select a number", c(1, 2, 3))
})
output$mydateUI <- renderUI({
dateInput("mydate", "Enter a date")
})
output$summary <- renderText({
return(paste(input$mytext, input$mynumber))
})
}
shinyApp(ui, server)
You can also create a reset button by assigning NULL to your reactive values object.
See this RStudio Shiny article on Using Action Buttons: http://shiny.rstudio.com/articles/action-buttons.html. Specifically, read the sections titled Pattern 4 - Reset buttons and Pattern 5 - Reset on tab change. Examples (including code) are provided in the article.
The article provides solutions that don't require additional packages if that's a concern.