00539_class_definition_outside_of_Shoes.app_block.mdown

class definition outside of Shoes.app block

If you want to define class outside of Shoes.app block, attention of self. Plseae run and read the following snippets.

This tip was created in the discussion with Paul Harris on the Shoes course 3rd batch.

# sample69.rb
class Sheep
  attr_writer :avatar
  
  def draw x, y
    @avatar.move x, y
  end
end
 
Shoes.app :width => 150, :height => 100 do
  s = Sheep.new
  s.avatar = oval 0, 0, 20, 20
  
  a = animate do |i|
    s.draw i, i
    a.stop if i > 50
  end
end

sample69.png

# sample69-1.rb
class Sheep
  def initialize
    @avatar = $app.oval 0, 0, 20, 20
  end
  
  attr_writer :avatar
  
  def draw x, y
    @avatar.move x, y
  end
end
 
Shoes.app :width => 150, :height => 100 do
  $app = self
  s = Sheep.new
 
  a = animate do |i|
    s.draw i, i
    a.stop if i > 50
  end
end

sample69-1.png

Another way of recreating sample69.

# sample69-2.rb
class Sheep < Shoes::Widget
  def initialize
    oval 0, 0, 20, 20
  end
  
  def run x, y
    move x, y
  end
end
 
Shoes.app :width => 150, :height => 100 do
  s = sheep
 
  a = animate do |i|
    s.run i, i
    a.stop if i > 50
  end
end

sample69-2.png

Another way of recreating sample69.

Note

In above sample69-2.rb, I use the method name run instead of draw. Because Shoes has already defined draw method, hence if I use the same name, it is overloaded and Shoes can't open app window.

Policeman

The sample69.rb, sample69-1.rb worked well with Shoes-0.r1263.

The sample69-2.rb also worked well after a bit edited like this:

class Sheep < Widget   --->   class Sheep < Shoes::Widget