module ActiveRecord::Acts::List::InstanceMethods

All the methods available to a record that has had acts_as_list specified. Each method works by assuming the object to be the item in the list, so chapter.move_lower would move that chapter lower in the list of all chapters. Likewise, chapter.first? would return true if that chapter is the first in the list of all chapters.

Public Instance Methods

decrement_position() click to toggle source

Decrease the position of this item without adjusting the rest of the list.

# File lib/acts_as_list/active_record/acts/list.rb, line 148
def decrement_position
  return unless in_list?
  update_attribute position_column, self.send(position_column).to_i - 1
end
first?() click to toggle source

Return true if this object is the first in the list.

# File lib/acts_as_list/active_record/acts/list.rb, line 154
def first?
  return false unless in_list?
  self.send(position_column) == acts_as_list_top
end
higher_item() click to toggle source

Return the next higher item in the list.

# File lib/acts_as_list/active_record/acts/list.rb, line 166
def higher_item
  return nil unless in_list?
  acts_as_list_class.find(:first, :conditions =>
    "#{scope_condition} AND #{position_column} = #{(send(position_column).to_i - 1).to_s}"
  )
end
in_list?() click to toggle source

Test if this record is in a list

# File lib/acts_as_list/active_record/acts/list.rb, line 182
def in_list?
  !send(position_column).nil?
end
increment_position() click to toggle source

Increase the position of this item without adjusting the rest of the list.

# File lib/acts_as_list/active_record/acts/list.rb, line 142
def increment_position
  return unless in_list?
  update_attribute position_column, self.send(position_column).to_i + 1
end
insert_at(position = acts_as_list_top) click to toggle source

Insert the item at the given position (defaults to the top position of 1).

# File lib/acts_as_list/active_record/acts/list.rb, line 89
def insert_at(position = acts_as_list_top)
  insert_at_position(position)
end
last?() click to toggle source

Return true if this object is the last in the list.

# File lib/acts_as_list/active_record/acts/list.rb, line 160
def last?
  return false unless in_list?
  self.send(position_column) == bottom_position_in_list
end
lower_item() click to toggle source

Return the next lower item in the list.

# File lib/acts_as_list/active_record/acts/list.rb, line 174
def lower_item
  return nil unless in_list?
  acts_as_list_class.find(:first, :conditions =>
    "#{scope_condition} AND #{position_column} = #{(send(position_column).to_i + 1).to_s}"
  )
end
move_higher() click to toggle source

Swap positions with the next higher item, if one exists.

# File lib/acts_as_list/active_record/acts/list.rb, line 104
def move_higher
  return unless higher_item

  acts_as_list_class.transaction do
    higher_item.increment_position
    decrement_position
  end
end
move_lower() click to toggle source

Swap positions with the next lower item, if one exists.

# File lib/acts_as_list/active_record/acts/list.rb, line 94
def move_lower
  return unless lower_item

  acts_as_list_class.transaction do
    lower_item.decrement_position
    increment_position
  end
end
move_to_bottom() click to toggle source

Move to the bottom of the list. If the item is already in the list, the items below it have their position adjusted accordingly.

# File lib/acts_as_list/active_record/acts/list.rb, line 115
def move_to_bottom
  return unless in_list?
  acts_as_list_class.transaction do
    decrement_positions_on_lower_items
    assume_bottom_position
  end
end
move_to_top() click to toggle source

Move to the top of the list. If the item is already in the list, the items above it have their position adjusted accordingly.

# File lib/acts_as_list/active_record/acts/list.rb, line 125
def move_to_top
  return unless in_list?
  acts_as_list_class.transaction do
    increment_positions_on_higher_items
    assume_top_position
  end
end
remove_from_list() click to toggle source

Removes the item from the list.

# File lib/acts_as_list/active_record/acts/list.rb, line 134
def remove_from_list
  if in_list?
    decrement_positions_on_lower_items
    update_attribute position_column, nil
  end
end