java教程-5-事件驱动及常用组件.ppt

第五章事件处理机制

及常用组件Event-drivenprogramming1.监听器类:一个使用了专门事件监听器接口的类,该类必须实现接口中的方法.5.2注册监听器方法监听器类必须使用与事件源相对应的接口(例：ActionListener)，从而必须提供接口中的方法：actionPerformed（ActionEventevent)的实现，此方法即是与事件相关联的事件驱动方法四.用匿名类简化程序在例ButtonTest.java中，每个按钮需要同样的处理：1.使用字符串构造按钮2.把按钮添加到面板3.用适当的颜色构造一个监听器4.注册动作监听器voidmakeButton(Stringname,colorbcolor){JButtonbutton=newJButton(name);add(button);Coloractionact=new//监听器对象Coloraction(bcolor);button.addActionListener(act);}ButtonPanel构造器变为：makeButton(“yellow”,Color.yellow);makeButton(“blue”,Color.blue);makeButton(“red”,Color.red);button.addActionListener(newActionListener(){publicvoidactionPerformed(actionEventevent){setBackground(bcolor);repaint()}});}例：NonameTest.java5.3窗口事件与窗口相关的事件源是WindowEventpublicinterfacewindowListener{voidwindowOpened(WindowEvente)｛｝;voidwindowClosing(WindowEvente)｛｝;voidwindowClosed(WindowEvente)｛｝;voidwindowIconified(WindowEvente)｛｝;voidwindowDeiconified(WindowEvente)｛｝;voidwindowActivated(WindowEvente)｛｝;voidwindowdeactivated(WindowEvente)｛｝;}每个具有不止一个方法的AWT监听器接口都有一个实现了它的所有方法,但却不做任何工作的适配器类.例:定义一个类,扩展WindowAdapter类,继承六个空方法,重写WindowClosing():frame.addWindowListener(newWindowAdapter(){publicvoidwindowClosing(WindowEvente){System.exit(0);}}})；AWT事件类的继承关系ActionEventItemAdjustmentEventKeyEventComponentEventMouseEventContainerEventTextEventFocusEventWindowEventActionListenerKeyListenerAdjustmentListenerContainerListenerComponentListenerTextListenerFocusListenerWindowListenerMouseListenerItemListenerMouseMotionListenerComponentAdapterContainerAdapterFocusAdapterKe