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$to_alert){
shinyalert(title = "Save your work before changing tab", type = "warning",showConfirmButton = TRUE)
updateTabsetPanel(session, inputId = "tabselected", selected = "Tab1")
}
})
}
shinyApp(ui = ui, server = server)
I'm building a Shiny app where I need to take inputted dates and use them in a section of code that only runs on a button click.
For the life of me I cannot find an example on here or in documentation that I can get to work.
For the reprex example I simply want to print the inputted dates in the main panel once the 'Run Report' button is clicked.
I've iterated the server code for hours, but cannot get this to work.
UI:
fluidPage(titlePanel('File download'),
sidebarLayout(
sidebarPanel(
dateRangeInput(
inputId = "date.range",
label = "Select Date Range",
start = Sys.Date() - 2,
end = Sys.Date() - 1
),
actionButton(inputId = "runReport",
label = "Run Report")
),
mainPanel(verbatimTextOutput("date.text"))
))
... and server:
function(input, output, session) {
eventReactive(input$runReport, {
output$date.text <- renderPrint({
paste0(as.character(input$date.range[1]), "to", as.character(input$date.range[2]))
})
})
}
How about this:
ui <- fluidPage(titlePanel('File download'),
sidebarLayout(
sidebarPanel(
dateRangeInput(
inputId = "date.range",
label = "Select Date Range",
start = Sys.Date() - 2,
end = Sys.Date() - 1
),
actionButton(inputId = "runReport",
label = "Run Report")
),
mainPanel(verbatimTextOutput("date.text"))
))
server <- function(input, output, session) {
dates <- eventReactive(input$runReport, {
input$date.range
})
output$date.text <- renderPrint({
paste0(as.character(dates()[1]), " to ", as.character(dates()[2]))
})
}
shinyApp(ui, server)
In what's above, you use eventReactive() to update the dates() object only when the button is pushed. Then you do not need the reactive around the print statement because its inputs will automatically update when the button is pushed. This answer was instructive.
writing with a shiny question. I have a navbarPage, id = "navbar", and in the navbarMenu user can select one among several tabPanels. Each tabPanel is assigned a value (value = 1, value = 2, etc). So input$navbar is reactive value with the value of the selected tabPanel.
I have a reactive expression defined which reacts to the changing of the tabPanel (reacts based on input$navbar). What I actually want is for this to react to navigating to a particular tabPanel, but not navigating away from that tabPanel. So, when input$navbar changes from 1 to 2 I want a reaction, but when changing from 2 to 1 no reaction. How can I achieve this?
Here is relevant snippet of my code, I don't think I need a full reproducible example for this but let me know if I'm wrong.
#ui snippet
navbarPage(id = "navbar",
navbarMenu(title = "Title",
tabPanel(title = "tp1", value = 1),
tabPanel(title = "tp2", value = 2),
#more tabPanels and ui stuff...
#server snippet
rctvfx <- reactive({
#want this to react only when input$navbar changes from ==1 to ==2
input$navbar
isolate({
#do stuff
})
})
You can use an if statement. This makes sure the code only runs if the user navigated to the corresponding tab.
library(shiny)
shinyApp(
ui = navbarPage(
"App Title",
id = "navbar",
tabPanel("Plot"),
navbarMenu(
"More",
tabPanel("Summary"),
"----",
"Section header",
tabPanel("Table")
)
),
server = function(input, output){
observe({
if (req(input$navbar) == "Table")
message("Table has been selected")
if (req(input$navbar) == "Plot")
message("Plot has been selected")
})
}
)
I would recomment do use observe rather than reactive to make sure everything runs even if all observers for the reactive are idle.
Another example of the same answer as above
library(shiny)
shinyApp(
ui = navbarPage(
"App Title",
id = "navbar",
tabPanel("Plot"),
navbarMenu(
"More",
tabPanel("Summary"),
tabPanel("Table"),
mainPanel(dataTableOutput("d"))
)
),
server = function(input, output){
output$d = renderDataTable({
if ((input$navbar) == "Table") {
head(mtcars)
} else {
((input$navbar) == "Plot")
head(iris)
}
})
}
)
When I filter a list of states in Shiny for: "New" I can choose only one state. After that the list is restarting and I have to put: "New" again in order to find a state contains "New" in name. I would like to filter states and choose more states at one time.
Below I added a picture and a code which present my goal.
Picture
library(shiny)
ui <- fluidPage(
sidebarLayout(
sidebarPanel(
selectizeInput(
'e2', '2. Multi-select', choices = state.name, multiple = TRUE
)
),
mainPanel(
verbatimTextOutput('ex_out')
)
)
)
server <- function(input, output) {
output$ex_out <- renderPrint({
sapply(sprintf('e%d', 2), function(id) {
input[[id]]
})
})
}
shinyApp(ui = ui, server = server)
I would like to implement a 'Reset inputs' button in my shiny app.
Here is an example with just two inputs where I'm using the update functions to set the values back to the default values:
library(shiny)
runApp(list(
ui = pageWithSidebar(
headerPanel("'Reset inputs' button example"),
sidebarPanel(
numericInput("mynumber", "Enter a number", 20),
textInput("mytext", "Enter a text", "test"),
tags$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.