如何在Jruby代码中翻译Java内部类的使用

Question

我试图与Java Swing一起玩Jruby：在这里和那里以示例为例，我试图将它们从纯Java转换为Jruby。效果很好，尤其是在阅读了专用于jruby的零件之后。

但是，有些东西我仍然不知道如何翻译。

例如，从Horstmann书中挑选此Java代码，我该如何正确翻译成Jruby？在此代码（在JPANEL构造函数中）中，我们依靠内部类用于Mouseadapter。其余的很容易。

如何翻译这种内部（或更充分地"匿名"类）？

Answer 1

只需重构/调整零件即可为您工作，例如

frame = javax.swing.JFrame.new
frame.title = "MouseTest"
frame.set_size(300, 200)
frame.add_window_listener do |evt|
  if evt.getID == java.awt.event.WindowEvent::WINDOW_CLOSING
    java.lang.System.exit(0)
  end
end
class MousePanel < Java::JavaxSwing::JPanel
   SQUARELENGTH = 10; MAXNSQUARES = 100;
  def initialize
    super
    @squares = []; @current = nil
    add_mouse_listener self
    add_mouse_motion_listener self
  end
  def add(x, y)
    if @squares.size < MAXNSQUARES
       @current = @squares.size
       @squares << Point.new(x, y)
       repaint
    end
  end
  def remove(n)
    return if (n < 0 || n >= @squares.size)
    @squares.pop
    @squares[n] = @squares[@squares.size];
    @current = nil if @current == n
    repaint
  end
  def paintComponent(graphics)
    super
    @squares.each { |square| do_draw(graphics, square) }
  end
  def do_draw(graphics, square)
    graphics.drawRect(
      square.x - SQUARELENGTH / 2,
      square.y - SQUARELENGTH / 2,
      SQUARELENGTH, SQUARELENGTH
    )
  end
  private :do_draw
  include java.awt.event.MouseListener
  [ 'mouseEntered', 'mouseExited', 'mouseReleased' ].each do |method|
    class_eval "def #{method}(evt); end"
  end
  def mousePressed(evt)
    puts "mousePressed #{evt}"
  end
  def mouseClicked(evt)
    puts "mouseClicked #{evt}"
  end
  include java.awt.event.MouseMotionListener
  def mouseMoved(evt)
    puts "mouseMoved #{evt}"
  end
  def mouseDragged(evt)
    puts "mouseDragged #{evt}"
  end
end
frame.content_pane.add MousePanel.new
frame.show

注意所有更新的 *add_xxx_listener出现...

将其放入要点以供可读性/伪性（包括原始代码）：https：//gist.github.com/kares/8538048