SelectInput and Leaflet not connecting - shiny

Question

I am trying to use shinyApp with the leaflet package. I have tried using the "SelectInput" function in the dashboard to create a reactive map based on the input selected(country).However, I am not able to make the leaflet and the SelectInput connect with each other.
Here is my code:
library(shiny)
library(leaflet)
ui <- (fluidPage(
titlePanel(title = "Pig breeding countries in 2000 - Top 5"),
sidebarLayout(
sidebarPanel(
selectInput(inputId = "country",
label = "Select a country to view it's values (you can choose more than one):",
c("Brazil", "China", "Russia", "USA", "Vietnam"), multiple = TRUE
)
),
#mainPanel must be outside the sidebarLayout argument
mainPanel(leafletOutput("mymap", height = "500"),
leafletOutput("country")
))
)
)
server <- (function(input, output){
output$mymap <- renderLeaflet(input$country)
output$mymap <- renderLeaflet({
mymap = leaflet()
setView(mymap, lng = -16.882374406249937, lat = -1.7206857960062047, zoom = 0)
mymap = addProviderTiles(mymap, provider = "CartoDB.Positron")
mymap = addMarkers(mymap,lng = 101.901875, lat = 35.486703, popup = "China 35,500")
mymap = addMarkers(mymap,lng = -95.712891, lat = 37.090240, popup = "USA 6,267")
mymap = addMarkers(mymap,lng = 108.339537, lat = 14.315424, popup = "Vietnam 2,947")
mymap = addMarkers(mymap,lng = 37.618423, lat = 55.751244, popup = "Russia 3,070")
mymap = addMarkers(mymap,lng = -46.625290, lat = -23.533773, popup = "Brazil 3,020")}
})
shinyApp(ui, server)
Can someone advise how to link them?

Answer 1

There is no reactive environment between your drop-down selection and leaflet map in your code. Check in the below code to create reactive leaflet map.
library(shiny)
library(leaflet)
df <- read.csv("leaflet.csv")
ui <- (fluidPage(
titlePanel(title = "Pig breeding countries in 2000 - Top 5"),
sidebarLayout(
sidebarPanel( uiOutput("countrynames")
),
mainPanel(leafletOutput("mymap", height = "500")
))
)
)
server <- function(input, output){
output$countrynames <- renderUI({
selectInput(inputId = "country", label = "Select a country to view it's values (you can choose more than one):",
c(as.character(df$country)))
})
map_data <- reactive({
data <- data.frame(df[df$country == input$country,])
data$popup <- paste0(data$country, " ", data$number)
return(data)
})
output$mymap <- renderLeaflet({
leaflet(data = map_data()) %>%
# setView( lng = -16.882374406249937, lat = -1.7206857960062047, zoom = 0) %>%
addProviderTiles( provider = "CartoDB.Positron") %>%
addMarkers(lng = ~lng, lat = ~lat, popup = ~popup)
# addCircles(lng = ~lng, lat = ~lat, popup = ~popup)
})
}
shinyApp(ui, server)
Below is the csv file i have imported in code.
structure(list(lng = c(101.901875, -95.712891, 108.339537, 37.618423
), lat = c(35.486703, 37.09024, 14.315424, 55.751244), country = structure(c(1L,
3L, 4L, 2L), .Label = c("China", "Russia", "USA", "Vietnam"), class = "factor"),
number = c(35500L, 6267L, 2947L, 3070L)), .Names = c("lng",
"lat", "country", "number"), class = "data.frame", row.names = c(NA,
-4L))