闪亮错误is.na（）应用于类型为'NULL'的非（列表或向量）

Question

I have a problem with my shiny app. I try to make second selectInput ( model ) to be dependent from choice made in first selectInput ( marka ) but it still not working.

I found this topic Using the input from updateSelectInput and it works on my computer so i did exactly the same thing with my data (there are in PogromcyDanych package). Unfortunately it's not working, I'm hopeless. I get the warning message:

Warning in run(timeoutMs) :
  is.na() applied to non-(list or vector) of type 'NULL'
Warning in run(timeoutMs) : 

Below there are my server.R and ui.R files:

library(shiny)
library(PogromcyDanych)
library(dplyr)

shinyServer(function(input, output, session) {

   dane <- auta2012

   observe({
      marka <- input$Marka
      ktore <- dane %>%
         filter(Marka == marka) %>%
         arrange(Model) %>%
         select(Marka, Model)
      updateSelectInput(session, "model", 
                        choices = levels(factor(ktore$Model)), 
                        selected = levels(factor(ktore$Model))[1])
   })

   dane.cena <- reactive({
      dane %>% 
         filter(Marka == input$Marka, Model == input$Model)
   })

})

ui:

library(shiny)
library(PogromcyDanych)
dane <- auta2012

shinyUI(fluidPage(
  titlePanel("Znajdź swój samochód!"),
  sidebarLayout(
    sidebarPanel(
      selectInput("marka",
                  "Wybierz markę",
                  levels(dane$Marka),
                  levels(dane$Marka)[1]),

      selectInput("model",
                  "Wybierz model",
                  levels(dane$Model),
                  levels(dane$Model)[1])
    ),

    mainPanel(
      h1("Ceny samochodów:"),
      br(),
      tabsetPanel(
        tabPanel("Boxplot", plotOutput("boxplot", width = 500)),
        tabPanel("Histogram", plotOutput("histogram", width = 500)),
        tabPanel("Podsumowanie", verbatimTextOutput("podsumowanie")),
        tabPanel("Tabela", tableOutput("tabela"))
      )
    )
  )
))

Answer 1

You have a sintax error in the select input id! ( "Marka" and "Model" with capital letter)

  selectInput("Marka",
              "Wybierz markę",
              levels(dane$Marka),
              levels(dane$Marka)[1]),

  selectInput("Model",
              "Wybierz model",
              levels(dane$Model),
              levels(dane$Model)[1])