app_delegate.rb

# -*- coding: utf-8 -*-
class AppDelegate
  def application(application, didFinishLaunchingWithOptions:launchOptions)
    @window = UIWindow.alloc.initWithFrame(UIScreen.mainScreen.bounds)
    controller = MainViewController.alloc.init
    @window.rootViewController = UINavigationController.alloc.initWithRootViewController(controller)
    @window.makeKeyAndVisible
    true
  end
end
 
class MainViewController < UIViewController
  def viewDidLoad
    super
    button = UIBarButtonItem.alloc.initWithBarButtonSystemItem(UIBarButtonSystemItemBookmarks, target:self, action:'open_modal')
    self.view.backgroundColor = UIColor.whiteColor
    self.navigationItem.rightBarButtonItem = button
  end
 
  def open_modal
    modal   = ModalViewController.alloc.init
    nav = UINavigationController.alloc.initWithRootViewController(modal)
    self.presentModalViewController(nav, animated:true)
  end
end
 
class ModalViewController < UITableViewController
  def viewDidLoad
    super
    @obj = MyObject.new
 
    ## パターン1: 普通の呼び方 => dealloc は呼ばれる
    # button =  UIBarButtonItem.alloc.initWithBarButtonSystemItem(UIBarButtonSystemItemCancel, target:self, action:'dismiss_modal')
    # self.navigationItem.leftBarButtonItem = button
 
    ## パターン2: sugarcube + closure => dealloc が呼ばれないっぽい、ウゲー
    self.navigationItem.leftBarButtonItem =
    UIBarButtonItem.cancel {
      self.dismissViewControllerAnimated(true, completion:nil)
      # 解放手続き
      button = self.navigationItem.leftBarButtonItem
      button.clear_action
    }
  end
   
  def dismiss_modal
    self.dismissViewControllerAnimated(true, completion:nil)
  end
 
  def dealloc
    NSLog('dealloc ModalViewController')
    super
  end
end
 
class MyObject
  def dealloc
    NSLog("dealloc MyObject")
    super
  end
end

# @sugarcube_actionをnilにしないと解放されない
class UIBarButtonItem

  def clear_action
    @sugarcube_action = nil
  end
  
end