Can someone help me with this method?

Question

def positioning
  tasks = Painting.all.order(:position)
  increment = false
  tasks.each do |t|
    if !increment && t.position == self.position
      increment = true
      t.position += 1
      t.save
    elsif increment
      t.position += 1
      t.save
    end
  end
end

This method is for a before_save callback, and works when I add a new painting, but it's doing something wrong incrementing the other objects position and later when I want to update any object this is a problem.

Answer 1

Version 1 using update_attribute

paintings = Painting.where(:position >=self.position)
paintings.each do |painting|
  painting.update_attributes(:position, painting.position + 1)
end

Version 2 using hash

paintings = Painting.where(:position >=self.position)
paintings.each do |painting|
  paintingHash = Hash.new
  paintingHash["position"]=painting.position+1
  painting.update(paintingHash)
end

The description is for version 2

line 1 find all paintings with position higher than current

line 2 start an itteration through the selected paintings

line 3 create new hash used for updating

line 4 assign value to a variable in the hash equaling to origional position +1

line 5 execute update

line 6 end he iteration

Answer 2

Try this?

def positioning
  tasks = Painting.all.order(:position)
  increment = false
  tasks[self.position..-1].each do |t|
    t.position += 1
    t.save
  end
end

This allows you to effectively loop through only the ones you want to increment. Since you already have all the tasks in hand from the first line, this doesn't cost anything more that I can tell.

I'm also not entirely sure if your position is 0 based or 1 based. my code assumes 0 based but if not you'll need to tweak that indexing line.