Menu

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Menu creates application menu bars and native standard menu items.

Appearance

Runnable example

require "uing"

UIng.init

UIng::Menu.new("File") do
  append_item("Open").on_clicked do |window|
    window.try &.open_file
  end
  append_separator
  append_preferences_item.on_clicked do |window|
    window.try &.msg_box("Preferences", "Preferences clicked")
  end
  append_separator
  append_quit_item
end

UIng::Menu.new("Edit") do
  append_check_item("Check", checked: false).on_clicked do |_menu_window|
    # No-op
  end
  append_separator
  append_item("Click").on_clicked do |window|
    window.try &.msg_box("Click", "Click menu clicked")
  end
end

UIng::Menu.new("Help") do
  append_about_item.on_clicked do |window|
    window.try &.msg_box("About", "Menu example")
  end
end

# Window must be created after menu finalized.
Window = UIng::Window.new("Menu Example", 300, 50, menubar: true) do
  on_closing do
    UIng.quit
    true
  end

  show
end

UIng.on_should_quit do
  Window.destroy unless Window.released?
  true
end

{% if flag?(:darwin) %}
  label = UIng::Label.new("The Mac menu bar is at the top of the screen.")
  Window.child = label
{% end %}

UIng.main

UIng.uninit

Usage notes

• Menu items come in the following forms:

  Type	Factory method	Purpose
  Regular item	append_item(name)	Runs a command.
  Check item	append_check_item(name, checked:)	Represents an on/off state. Read or change it with checked? and checked=.
  Preferences item	append_preferences_item	Opens application preferences.
  About item	append_about_item	Shows application information.
  Quit item	append_quit_item	Exits the application. Configure shutdown through UIng.on_should_quit.
  Separator	append_separator	Visually separates related groups of items.

• Finalize all menus before creating the first Window, and set menubar: true.

• Menu callbacks receive an optional Window because some platform-level actions may not have one.
• Preferences, About, and Quit are standard items that follow OS menu conventions. Their label, placement, and surrounding separators vary by OS, so they may not appear in the Menu or order where you add them.
• You can add only one append_preferences_item, append_about_item, and append_quit_item item per application.

API reference · Gallery source