Keep plots and input values when switching between tabs - r

Question

I have a shinydashboard app with two different tab panels. Each tab has different input values and both of them generate a graph when an action button is clicked.
Whenever I switch between these tabs, their respective graphs disappear and input values are reset to default.
I want to keep the tabs in their user modified states (i.e keep both graphs and inputs) even when the user decides to switch between the panels.
Code
library(shiny)
library(shinydashboard)
ui <- fluidPage(
dashboardPage(
dashboardHeader(title = "DASHBOARD"),
dashboardSidebar(
uiOutput("mysidebar"),
),
dashboardBody(
tabsetPanel(type = "tabs", id = "tab",
tabPanel("Tab1", fluid = TRUE, value = 1,plotOutput("A")),
tabPanel("Tab2", fluid = TRUE, value = 2, plotOutput("B"))
)
)
)
)
server <- function(input, output, session){
output$mysidebar <- renderUI({
if(input$tab == 1){
tagList(
sliderInput(inputId = "Sample",
label = "Enter Number of Samples:",
min = 1000, max = 100000,
value = 10000),
fluidRow(
column(6,
actionButton(inputId = "b1", label = "Generate"))
)}
if(input$tab == 2){
tagList(
sliderInput(inputId = "Weight",
label = "Enter Weight:",
value = 100),
fluidRow(
column(6,
actionButton(inputId = "b2", label = "Generate"))
)}
p1<- eventReactive(input$b1, {
#creating a dataframe using input "Sample" in tab1 - Rough example
df <- input$Sample
})
output$SA <- renderPlot({
plot(df)
})
p2 <- eventReactive(input$b2, {
#creating a dataframe using input "Weight" in tab2-- Rough example
df2 <- input$Weight
})
output$A <- renderPlot({
plot(p1())
})
output$B <- renderPlot({
plot(p2())
})
}

Answer 1

I'd much rather you use show and hide functionality within shinyjs package like example below, this way the values will be preserved when you switch between the Tabs
library(shiny)
library(shinyjs)
library(shinydashboard)
ui <- fluidPage(
dashboardPage(
dashboardHeader(title = "DASHBOARD"),
dashboardSidebar(
useShinyjs(),
sliderInput("Sample","Enter Number of Samples:",min = 1000, max = 100000,value = 10000),
sliderInput("Weight","Enter Weight:",min = 1, max = 1000,value = 100),
fluidRow(column(6,actionButton("b1","Generate"),actionButton("b2","Generate")))
),
dashboardBody(
tabsetPanel(type = "tabs", id = "tab",
tabPanel("Tab1", fluid = TRUE, value = 1,plotOutput("A")),
tabPanel("Tab2", fluid = TRUE, value = 2, plotOutput("B"))
)
)
)
)
server <- function(input, output, session){
observe({
if(input$tab == 1){
show("Sample")
show("b1")
hide("Weight")
hide("b2")
}
if(input$tab == 2){
hide("Sample")
hide("b1")
show("Weight")
show("b2")
}
})
p1<- eventReactive(input$b1,{
df <- rnorm(input$Sample)
})
output$SA <- renderPlot({
plot(df)
})
p2 <- eventReactive(input$b2,{
df2 <- rnorm(input$Weight)
})
output$A <- renderPlot({plot(p1())})
output$B <- renderPlot({plot(p2())})
}
shinyApp(ui, server)

Answer 2

The following code keeps the plots and inputs, by using reactiveValues.
library(shiny)
library(shinydashboard)
ui <- dashboardPage(dashboardHeader(title = "DASHBOARD"),
dashboardSidebar(
uiOutput("mysidebar")
),
dashboardBody(
tabsetPanel(type = "tabs", id = "tab",
tabPanel("Tab1", value = 1,plotOutput("SA")),
tabPanel("Tab2", value = 2, plotOutput("SA1"))
)
)
)
server <- function(input, output, session){
slider_react <- reactiveValues(b1=10000, b2 = 100)
observe({
if (input$tab == 1){
output$mysidebar <- renderUI({
tagList(
sliderInput(inputId = "Sample",
label = "Enter Number of Samples:",
min = 1000, max = 100000,
# value = 10000),
value = slider_react$b1),
actionButton(inputId = "b1", label = "Generate"))
})
}
if(input$tab == 2){
output$mysidebar <- renderUI({
tagList(
sliderInput(inputId = "Weight",
label = "Enter Weight:",
min=0, max=1000,
# value = 100),
value = slider_react$b2),
actionButton(inputId = "b2", label = "Generate"))
})
}
})
df_react <- reactiveValues(a1=NULL, a2=NULL)
p1<- observeEvent(input$b1, {
#creating a dataframe using input "Sample" in tab1 - Rough example
df <- runif(input$Sample, 0, 100)
slider_react$b1 = input$Sample
df_react$a1 = df
})
p2 <- observeEvent(input$b2, {
#creating a dataframe using input "Weight" in tab2-- Rough example
df2 <- runif(input$Weight, 0, 100)
slider_react$b2 = input$Weight
df_react$a2 = df2
})
output$SA <- renderPlot({
req(df_react$a1)
plot(df_react$a1)
})
output$SA1 <- renderPlot({
req(df_react$a2)
plot(df_react$a2)
})
}
shinyApp(ui, server)