Class: Charming::Presentation::Components::List

Inherits:
Charming::Presentation::Component show all
Includes:
KeyboardHandler
Defined in:
lib/charming/presentation/components/list.rb

Overview

List is a vertically-scrollable selectable list. Supports keyboard navigation (up/down/home/end, Enter to activate) and mouse click selection. When a height is given, the list renders a fixed-height window over its items with auto-scroll keeping the selected item in view.

Constant Summary collapse

KEY_ACTIONS =

Maps navigation key symbols to instance methods consumed by the KeyboardHandler mixin: :up moves selection up, :down moves down, :home jumps to first item, :end jumps to last. See Viewport#KEY_ACTIONS and Table#KEY_ACTIONS for identical pattern.

{
  up: :move_up,
  down: :move_down,
  home: :move_home,
  end: :move_end
}.freeze

Constants included from KeyboardHandler

KeyboardHandler::VIM_KEYMAP

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from View

#focused?, #layout_assigns

Constructor Details

#initialize(items:, selected_index: 0, height: nil, label: nil, theme: nil, keymap: :vim) ⇒ List

items is the array of selectable objects. selected_index defaults to 0. height optionally constrains the visible window; label is a callable that extracts the display string from an item (defaults to ‘to_s`). keymap selects the keybinding style (`:vim` enables h/j/k/l → left/down/up/right).



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# File 'lib/charming/presentation/components/list.rb', line 30

def initialize(items:, selected_index: 0, height: nil, label: nil, theme: nil, keymap: :vim)
  super(theme: theme)
  @items = items
  @selected_index = selected_index
  @height = height
  @label = label || :to_s.to_proc
  @keymap = keymap
  clamp_position
end

Instance Attribute Details

#items ⇒ Object (readonly)

The item array and the currently selected index within it.



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# File 'lib/charming/presentation/components/list.rb', line 24

def items
  @items
end

#selected_index ⇒ Object (readonly)

The item array and the currently selected index within it.



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# File 'lib/charming/presentation/components/list.rb', line 24

def selected_index
  @selected_index
end

Instance Method Details

#handle_key(event) ⇒ Object

Handles key events. Returns ‘[:selected, item]` on Enter when an item is selected; otherwise delegates to the KeyboardHandler for navigation keys.



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# File 'lib/charming/presentation/components/list.rb', line 42

def handle_key(event)
  return [:selected, selected_item] if Charming.key_of(event) == :enter && selected_item

  super
end

#handle_mouse(event) ⇒ Object

Handles mouse events: a click within the visible window selects the clicked row. Returns :handled on a successful click, nil otherwise.



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# File 'lib/charming/presentation/components/list.rb', line 50

def handle_mouse(event)
  return nil unless @height
  return nil unless event.respond_to?(:click?) && event.click?

  clicked = event.y
  return nil if clicked.negative? || clicked >= visible_items.length

  @selected_index = viewport_start + clicked
  clamp_position
  :handled
end

#render ⇒ Object

Renders the visible window of items, prefixing each with “> ” (and applying the selected style) or “ ”.



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# File 'lib/charming/presentation/components/list.rb', line 69

def render
  visible_items.each_with_index.map do |item, index|
    render_item(item, viewport_start + index)
  end.join("\n")
end

#selected_item ⇒ Object

Returns the currently selected item, or nil when the list is empty.



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# File 'lib/charming/presentation/components/list.rb', line 63

def selected_item
  items[selected_index]
end