navbar Page and wrong update of ggvis plot Shiny

Question

Hi
I just create Shiny app. But there is a little problem when I want to present my Shiny app in navbarPage way. I mean, when I add new navbarPage named Introduction everithing works fine with plot till... I come back to Introduction navbarPage and then one again come back to Plot navbarPage, plot does not work well. What happended? How to fix it?

ui.R

library(dplyr)
library(shiny)
library(ggvis)

shinyUI(
  navbarPage("",
             tabPanel("Introduction",
                      fluidRow(
                        column(3,
                               wellPanel(
                               )

                        ),

                        column(9,
                               br(),br(),br(),
                               h5("This screen will soon display a brief introduction to the project.")
                        ) 
                      )
             ),     
             tabPanel("Plot",
                      fluidRow(
                        column(3,
                          radioButtons("dataset", label = h4("Choose dataframe"),
                                       choices = list("Item" = "df1", "Task" = "df2")),
                          selectInput("yvar", "Y-axis variable", axis_vars_y, selected = "number"),
                          uiOutput("slider")

                          ),
                    column(9,
                          ggvisOutput("plot")
        )
    )
  )
)
)

server.R

library(shiny)
library(dplyr)
library(magrittr)
library(lazyeval)

shinyServer(function(input, output) {

  datasetInput <- reactive({
    switch(input$dataset,
           df1 = df1,
           df2 = df2)
  })

  axis_vara_y <- reactive({
    switch(input$yvar,
           number = 2,
           number2 = 3)
  }) 

    output$slider <- renderUI({
      sliderInput("inslider","Slider", min   = round(min(datasetInput()[,axis_vara_y()]),0)-1, 
                                       max   = round(max(datasetInput()[,axis_vara_y()]),0)+1,
                                       value = c(round(min(datasetInput()[,axis_vara_y()]),0)-1, 
                                                 round(max(datasetInput()[,axis_vara_y()]),0)+1),
                                       step = 0.5)
})

data <- reactive({
  filteredData <- datasetInput()
  axisData <- axis_vara_y()

  if(!is.null(input$inslider)){
    filteredData <- filteredData %>%
      filter(filteredData[,axisData] >= input$inslider[1],
             filteredData[,axisData] <= input$inslider[2])
  }

  if (nrow(filteredData) == 0){
    return (datasetInput())
  }else{
    return(filteredData)
  }
})
  data_two <- reactive({
    data() %>%
      mutate(id = 1:n())

  })  

  vis <- reactive({

    yvar_name <- names(axis_vars_y)[axis_vars_y == input$yvar]
    yvar <- prop("y", as.symbol(input$yvar))

    data_two %>%
      ggvis(x = ~name, y = yvar) %>%    
      layer_points(size := 120,
                 fill = ~name,
                 fillOpacity := 0.6)

  })
  vis %>% bind_shiny("plot")
})

global.R

df1_number <-sample(seq(1,20,0.01),20,replace = T)
df2_number <-sample(seq(1,20,0.01),20,replace = T)
df1_number2 <-sample(seq(1,5,0.01),20,replace = T)
df2_number2 <-sample(seq(1,5,0.01),20,replace = T)

df1 <- data.frame(name = rep(letters[1:4],each = 5), number = df1_number, number2 = df1_number2)
df2 <- data.frame(name = rep(letters[1:4],each = 5), number = df2_number, number2 = df2_number2)
axis_vars_y <- c("number" = "number", "number2" = "number2")

Answer 1

I've never had much luck putting ggvis inside of a reactive. Weird things happen like what you experienced. Try this.

shiny::runGist("https://gist.github.com/corynissen/9cdf1275f394e7945eb6")

You have to assign the y value in the data_two reactive, then run the ggvis outside of the reactive().