Hello!
I have a very simple Shiny app that is working. The user enters a value on box 1 and then in box 2 and then hits 'run'.
However, when the user hits backspace in one of the two numericInput cells until nothing is entered, the app crashes.
How could I prevent it from crashing? Thank you very much!
Here is my code:
library(shiny)
library(shinyjs)
ui <- fluidPage(
useShinyjs(),
actionButton("run", label = "Run calculations!"),
# Input 1
numericInput("inNumber1", label = "Input number 1",
value = 100, min = 10, max = 200, step = 10),
# Message that shows up if the value of inNumber1 is outside the allowed range:
hidden(h5("Enter a value between 10 and 200!",
id = "message1",
style = "font-weight:bold;color:orange;")),
uiOutput("inNumber2"),
# Message that shows up if the value of inNumber1 is outside the allowed range:
hidden(h5("Enter a value between 10 and the value of Input number 1!",
id = "message2",
style = "font-weight:bold;color:orange;")),
textOutput("out1"),
textOutput("out2")
)
server <- function(input, output, session) {
# Input 2 - dependent on Input 1
observeEvent(input$inNumber1, {
# Is input$inNumber1 outside the allowed range?
if (input$inNumber1 < 10 | input$inNumber1 > 200) {
shinyjs::show("message1")
} else {
shinyjs::hide("message1")
}
output$inNumber2 <- renderUI({
if (is.null(input$inNumber1)) return(NULL)
numericInput("inNumber2", label = "Input number 2",
value = 100, min = 10, max = input$inNumber1, step = 10)
})
})
observeEvent(input$inNumber2, {
# Is input$inNumber2 outside the allowed range?
if (input$inNumber2 < 10 | input$inNumber2 > input$inNumber1) {
shinyjs::show("message2")
} else {
shinyjs::hide("message2")
}
})
observeEvent(input$run, {
# Check Input 1:
number1 <- input$inNumber1
if (number1 < 10 | number1 > 200) {
warning1 <- "Input 1 must be between 10 and 200"
} else {warning1 <- renderText({NULL})}
output$out1 <- renderText({number1})
number2 <- input$inNumber2 # value 2
maxnumber2 <- input$inNumber1
if (number2 > maxnumber2) {
# warning(paste0("number2 must be lower than ", maxnumber2))
number2 <- maxnumber2
}
output$out2 <- renderText({number2})
})
}
shinyApp(ui, server)