Using instance variable from "Scene_A" in "Scene_B"

[PK8]

Basically, I need help figuring out how to use an instance variable from another scene (let's call it "Scene_A") in... let's call it Scene_B without relying on global variables to use it. I can be pretty rgss-stupid at times. So I was wondering if someone could kinda guide me on how to go about doing this step by step.

 

[Kain Nobel]

You could make it an object in Game_Temp (although I try to avoid using Game_Temp too, but sometimes you have to). Then just use $game_temp.punks_variable = ???

class Game_Temp
  attr_accessor :punks_variable
  alias_method :punk_gmtemp_init, :initialize
  def initialize
    @punks_variable = false
  end
end

Do the two scenes activate each other? At the end of the main loop or whenever Scene_A activates Scene_B (visa versa) you could do this in both classes...

class Scene_A
  def initialize(var)
    @var = var
    # ...Blah blah blah
  end
end

class Scene_B
  # Remember to do the same thing with the Initialize method here too...
  def update_command_cancel
    $game_system.se_play($data_system.cancel_se)
    $scene = Scene_A.new(@var)
  end
end

If Scene_A and Scene_B can be activated through other scenes, then I'd use the Game_Temp suggestion, but if not I'd just use the argument added to initialize in both scenes.

 

[Fustel]

Err... the basic idea behind class variables is that they CANNOT be accessed from outside the class or its descendant (you are sure you are speaking of a class variable, one beginning with @@ ?).
So, the only way I see to usre a Class_A class variable from Class_B is to make Class_B a descendant of Class_B. Or to make Class_A and Class_B descendant of the same Class_Parent.

--------------------------------------------------------------------------------------

1st solution if Class_A and Class_B share more the class variables

class Class_A
  def initialize
    @@z = 0
  end

  def z=( val)
    @@z = val
  end
end

class Class_B < Classe_A
end

--------------------------------------------------------------------------------------

2nd solution if Class_A and Class_B have just have the class variable to share

class Class_Parent
  def initialize
    @@z = 0
  end

  def z=( val)
    @@z = val
  end
end

class Class_A < Classe_Parent
end

class Class_B < Classe_Parent
end

--------------------------------------------------------------------------------------

and a 3td solution that came up while I was writing the previous ones

Just create an instance of a sharing 3rd class in both Class_A and Class_B (more practical if Class_A and Class_B have different parent classes)

class Class_Shared
  def initialize
    @@z = 0
  end

  def z=(val)
    @@z = val
  end
end

class Class_A
  attr_accessor :shared

  def initialize
    @shared = Class_Shared.new
    ...
  end
end

class Class_B
  attr_accessor :shared

  def initialize
    @shared = Class_Shared.new
    ...
  end
end

you can even have

class Class_A < Class_A_Parent
class Class_B < Class_B_Parent

when instanciating Class_A and Class_B like this

a = Class_A.new
b = Class_B.new

you get the shared class variable via

a.shared.z
b.shared.z

Hope I made no mistake....