renderLeaflet is not working in shiny app

Question

I am working with leaflet package to draw maps and plot lat and long on the plot. I am doing following in R.

m <- leaflet() %>%
addTiles() %>%  # Add default OpenStreetMap map tiles
addMarkers(lng=df_final$order_long, lat=df_final$order_lat)
m

It works perfectly fine in R console. But It doesn't work when I use it in shiny This is my ui.r code snippet

tabPanel("Order Locations", leafletOutput("map", width = "80%", height =  
"80%"))

and this is server.r code snippet

 output$map<- renderLeaflet({

 dataset<-dataUpload()
 leaflet() %>%
 addTiles() %>%  # Add default OpenStreetMap map tiles
 addMarkers(lng=dataset$order_long,lat=dataset$order_lat)
 })

It doesn't display anything. Where I am getting wrong. please help

Answer 1

This works, I made it as close to yours as possible. It doesn't like percentage heights apparently:

library(shiny)
library(leaflet)

r_colors <- rgb(t(col2rgb(colors()) / 255))
names(r_colors) <- colors()

ui <- fluidPage(
  actionButton("recalc", "New points"),
  mainPanel(
    tabsetPanel(
      tabPanel("Order Locations", leafletOutput("map",width="80%",height="400px")),
      tabPanel("Markers", verbatimTextOutput("markers"))
    )
  )
)

if (!file.exists("df_final.csv")){
  nmark <- 50
  hv <- 80
  df_final <- data.frame(order_long=runif(nmark,-hv,hv),
                         order_lat=runif(nmark,-hv,hv))
  write.csv(df_final,"df_final.csv",row.names=F)
}

server <- function(input, output, session) {

  dataUpload <- reactiveFileReader(1000, session, 'df_final.csv', read.csv)

  output$map <- renderLeaflet({
    leaflet() %>%
      addTiles() %>%
      addMarkers(lng=dataUpload()$order_long,lat=dataUpload()$order_lat)
  })
  output$markers <- renderPrint({print(dataUpload())})
}

shinyApp(ui, server)

Yielding: