on_current_view_changed

Comments

• Matthias

  January 2021 edited January 2021

  Hi Frank

  you can also simple use a block instead of a proc:

  mw = RBA::Application.instance.main_window
  mw.on_current_view_changed do |last|
    puts "viewchanged #{last.inspect}"
  end
  

  But you're right about the nil. The documentation was incorrect - there is no such parameter The master is already updated.

  But you do not need a global variable. This works for MainWindow as there is one one. But that's not a solution in other cases. One solution is to extend MainWindow to provide a new attribute you can use:

  module RBA
    class MainWindow
      attr_accessor :last_view
    end
  end
  
  mw = RBA::Application.instance.main_window
  mw.on_current_view_changed do
    puts "viewchanged #{mw.last_view ? mw.last_view.title : 'nil'} -> #{mw.current_view ? mw.current_view.title : ''}"
    mw.last_view = mw.current_view
  end
  

  Another approach is a more object-oriented one which works with an observer object:

  class CurrentViewObserver
    def initialize
      @mw = RBA::Application.instance.main_window
      @mw.on_current_view_changed += lambda { self.view_changed }
      @last_view = nil
    end
    def view_changed
      puts "viewchanged #{@last_view ? @last_view.title : 'nil'} -> #{@mw.current_view ? @mw.current_view.title : ''}"
      @last_view = @mw.current_view
    end
  end
  
  CurrentViewObserver::new
  

  Kind regards,

  Matthias