Single-Select Dropdown with glasstabs

Overview

glassSelect() is an animated single-select dropdown for Shiny.

It behaves like a standard Shiny input: input$<inputId> stores the selected value as a single character string, or NULL when nothing is selected.

It supports:

• optional labels
• search and clear controls
• built-in dark and light themes
• custom theming with glass_select_theme()
• selectable marker styles via check_style
• server-side updates with updateGlassSelect()

Basic usage

library(shiny)
library(glasstabs)

fruits <- c(
  Apple  = "apple",
  Banana = "banana",
  Cherry = "cherry",
  Mango  = "mango"
)

ui <- fluidPage(
  useGlassTabs(),
  glassSelect("pick", fruits),
  verbatimTextOutput("out")
)

server <- function(input, output, session) {
  output$out <- renderPrint(input$pick)
}

shinyApp(ui, server)

Initial selection

# No selection (default)
glassSelect("f", fruits)

# Pre-select one value
glassSelect("f", fruits, selected = "banana")

Optional label

glassSelect("f", fruits, label = "Choose a fruit")

Selection styles

glassSelect() supports three selection marker styles:

• "checkbox" (default)
• "check-only"
• "filled"

glassSelect("f1", fruits, check_style = "checkbox")
glassSelect("f2", fruits, check_style = "check-only")
glassSelect("f3", fruits, check_style = "filled")

Searchable and clearable

Search is enabled by default. You can also enable a clear control.

glassSelect(
  "f",
  fruits,
  searchable = TRUE,
  clearable = TRUE
)

To hide the search box:

glassSelect(
  "f",
  fruits,
  searchable = FALSE
)

Explicit “All” option

You can prepend an explicit “All” option:

glassSelect(
  "f",
  fruits,
  include_all = TRUE,
  all_choice_label = "All fruits",
  all_choice_value = "__all__"
)

This is useful when you want the UI to distinguish between: - no selection - a deliberate “All” selection

Server-side access

Read the current value directly from input$<inputId>:

server <- function(input, output, session) {
  observe({
  message("Selected: ", if (is.null(input$pick)) "NULL" else input$pick)
})
}

Reactive helper

If you want a small convenience wrapper, use glassSelectValue():

server <- function(input, output, session) {
  pick <- glassSelectValue(input, "pick")

  observe({
    print(pick())
  })
}

Updating choices and selection from the server

updateGlassSelect() can update: - available choices - current selection - selection marker style

observeEvent(input$filled, {
  updateGlassSelect(
    session,
    "pick",
    check_style = "filled"
  )
})

It follows Shiny-style update semantics:

• choices = NULL leaves choices unchanged
• selected = NULL leaves selection unchanged
• selected = character(0) clears the selection

ui <- fluidPage(
  useGlassTabs(),
  actionButton("subset", "Keep first 2 fruits"),
  actionButton("banana", "Select banana"),
  actionButton("clear", "Clear"),
  actionButton("filled", "Use filled style"),
  glassSelect("pick", fruits, clearable = TRUE),
  verbatimTextOutput("out")
)

server <- function(input, output, session) {
  output$out <- renderPrint(input$pick)

  observeEvent(input$subset, {
    updateGlassSelect(
      session,
      "pick",
      choices = fruits[1:2]
    )
  })

  observeEvent(input$banana, {
    updateGlassSelect(
      session,
      "pick",
      selected = "banana"
    )
  })

  observeEvent(input$clear, {
    updateGlassSelect(
      session,
      "pick",
      selected = character(0)
    )
  })
}

shinyApp(ui, server)

When choices is updated without selected, the widget keeps the current value if it still exists in the new set of choices.

Theming

Built-in presets

glassSelect("f", fruits, theme = "dark")
glassSelect("f", fruits, theme = "light")

Custom theme with glass_select_theme()

glassSelect(
  "f",
  fruits,
  theme = glass_select_theme(
    mode = "dark",
    accent_color = "#f59e0b"
  )
)

glassSelect(
  "f",
  fruits,
  theme = glass_select_theme(
    bg_color = "#1a0a2e",
    border_color = "#a855f7",
    text_color = "#ede9fe",
    accent_color = "#a855f7"
  )
)


#other themes
glassSelect(
  "f",
  fruits,
  theme = glass_select_theme(
    mode = "light",
    accent_color = "#2563eb"
  )
)

#more themes
glassSelect(
  "f",
  fruits,
  theme = glass_select_theme(
    mode = "light",
    bg_color = "#ffffff",
    border_color = "rgba(0,0,0,0.15)",
    text_color = "#111111",
    accent_color = "#111111",
    label_color = "#111111"
  )
)

Standalone usage

glassSelect() can be used without the tab widget. You only need useGlassTabs() to load the package CSS and JavaScript assets:

ui <- fluidPage(
  useGlassTabs(),
  glassSelect("region", c(North = "North", South = "South", East = "East")),
  verbatimTextOutput("out")
)

server <- function(input, output, session) {
  output$out <- renderPrint(input$region)
}

shinyApp(ui, server)