sidebarMenu is not storing the right values - r

Question

I have shainyApp which contains multiple dashboardPages, in each one of them i have sidebarMenu.
I am trying to get the name of the clicked tab.
That's an example code:
ui<-navbarPage("",
tabPanel("tab1",
dashboardPage(
dashboardHeader(),
dashboardSidebar(
sidebarMenu(id="menu1",
menuItem("a1", icon = icon("th"),tabName = "a1",selected = T),
menuItem("a2", icon = icon("th"),tabName = "a2")
)
),
dashboardBody()
)
),
tabPanel("tab2",
dashboardPage(
dashboardHeader(),
dashboardSidebar(
sidebarMenu(id="menu2",
menuItem("b1", icon = icon("th"),tabName = "b1",selected = T),
menuItem("b2", icon = icon("th"),tabName = "b2")
)
),
dashboardBody(
textOutput("text")
)
)
)
)
server <- function(input, output, session) {
output$text<-renderText({
input$menu2
})
}
shinyApp(ui,server)
The problem which I am facing is that input$menu2 has the value 'a1' at the beginning and not 'b1'
Is it a bug or am I doing something wrong here?
Appreciate your help on this
Thanks

Answer 1

Your program is working fine. It displays what was pre-selected in the first instance even when you go to second tab. Once you click on an item in the sidebar, say b2, it will display that until another item is clicked in the sidebar from either tab1 or tab2.
If you wish to display different plots or other information on each tab with its own sidebar, it can be done using a single dashboardPage. Just use conditionalPanel as shown below.
require(shiny)
require(shinydashboard)
require(shinyjs)
### create a simple app
ui <- dashboardPage(
title='Test Menus',
dashboardHeader(
title = 'Loading Menus'
),
dashboardSidebar(
conditionalPanel("input.navbar == 'tab1_val'",
div(id='tab1_sidebar',
#sliderInput('tab1_slider', 'tab1 slider', min=2,max=7,value=2),
sidebarMenu(id="menu1",
menuItem("a1", icon = icon("th"),tabName = "a1",selected = T),
menuItem("a2", icon = icon("th"),tabName = "a2")
)
)
),
conditionalPanel("input.navbar == 'tab2_val'",
div(id='tab2_sidebar',
#sliderInput('tab2_slider', 'tab2 slider', min=2,max=7,value=5),
sidebarMenu(id="menu2",
menuItem("b1", icon = icon("th"),tabName = "b1",selected = T),
menuItem("b2", icon = icon("th"),tabName = "b2")
)
)
)
),
dashboardBody(
useShinyjs(),
tabsetPanel(
id = "navbar",
tabPanel(title="tab1 title",id="tab1",value='tab1_val',
valueBoxOutput('tab1_valuebox'),
uiOutput("text1"),
plotOutput("plot1")
),
tabPanel(title="tab2 title",id="tab2",value='tab2_val',
valueBoxOutput('tab2_valuebox'),
uiOutput("text2"),
plotOutput("plot2")
)
)
)
)
server <- shinyServer(function(input, output, session) {
output$tab1_valuebox <- renderValueBox({
valueBox('1000',subtitle = "blah blah",icon = icon("car"),
color = "blue", print(input$menu1)
)
})
output$tab2_valuebox <- renderValueBox({
valueBox('2000',subtitle = "blah2 blah2",icon = icon("car"),
color = "red"
)
})
output$text1<-renderUI({
print(input$menu1)
})
output$text2<-renderUI({
print(input$menu2)
})
pt1 <- qplot(rnorm(500),fill=I("red"),binwidth=0.2,title="plotgraph1")
pt2 <- qplot(rnorm(600),fill=I("blue"),binwidth=0.2,title="plotgraph2")
output$plot1 = renderPlot({pt1})
output$plot2 = renderPlot({pt2})
#### on click of a tab1 valuebox
shinyjs::onclick('tab1_valuebox',expr={
# move to tab2
updateTabsetPanel(session, "navbar", 'tab2_val')
})
### on click of a tab2 valuebox
shinyjs::onclick('tab2_valuebox',expr={
# move to tab1
updateTabsetPanel(session, "navbar", 'tab1_val')
})
})
shinyApp(ui,server)
This is derived from one of two answers provided by #DeanAttali here. All credit goes to him.