event

• event可以被定义为某种信号代表什么事情发生了
• event object包含了那些pertinent properties之于event
  • getsource()
  • subclasses of EventObject:
• user action
  • click button:
  • click checkbox:
  • click a radio button:
  • press return:
  • select a new item:
  • window opened/closed:
  • mouse pressed/released:
  • key pressed/released:
• delegation model:
• （…）
• inner class handler: 专门创建GUI event对象
  • inner class: class是另一个class的member
• anonymous inner class: 必须extend a super class or implementan interface
• mouse event