《Java核心技术 卷I》用户界面AWT事件继承层次

AWT事件继承层次

EventObject类有一个子类AWTEvent，它是所有AWT事件类的父类。

Swing组件会生成更多其他事件对象，都直接拓展自EventObject而不是AWTEvent。

AWT将事件分为底层(low-level)事件和语义事件。

语义事件：表示用户的动作事件，例如点击按钮，调节滚动条。

底层事件：使得语义事件得以发生的事件，例如按下鼠标，移动鼠标等。

AWT事件类的继承关系图

java.awt.event包中最常用的语义事件类：

• ActionEvent(对应按钮点击，菜单选择，选择列表，文本域中按回车)
• AdjustmentEvent(用户调用滚动条)
• ItemEvent(用户从复选框或列表框中选择一项)

最常用的5个底层事件类是：

• KeyEvent(一个键按下或释放)
• MouseEvent(鼠标键按下、释放、移动、拖动)
• MouseWheelEvent(鼠标滚轮转动)
• FocusEvent(某个组件获得焦点或失去焦点)
• WindowEvent(窗口状态改变)

最重要的AWT监听器接口、事件和事件源

接口	方法	参数/访问方法	事件源
ActionListener	actionPerformed	ActionEvent getActionCommand getModifiers	AbstractButton JComboBox JTextField Timer
AdjustmentListener	adjustmentValueChanged	AdjustmentEvent getAdjustable getAdjustmentType getValue	JScrollbar
ItemListener	itemStateChanged	ItemEvent getItem getItemSelectable getStateChange	AbstractButton JComboxBox
FocusListener	focusGained focusLost	FocusEvent isTemporary	Component
KeyListener	keyPressed keyReleased keyTyped	KeyEvent getKeyChar getKeyCode getKeyModifiersText getKeyText isActionKey	Component
MouseListener	mousePressed mouseReleased mouseEntered mouseExited mouseClicked	MouseEvent getClickCount getX getY getPoint translatePoint	Component
MouseMotionListener	mouseDragged mouseMoved	MouseEvent	Component
MouseWheelListener	mouseWheelMoved	MouseWheelEvent getWheelRotation getScrollAmount	Component
WindowListener	windowClosing windowOpened windowIconfied windowDeiconified windowClosed windowActivated windowDeactivated	WindowEvent getWindow	Window
WindowFocusListener	windowGainedFocus windowLostFocus	WindowEvent getOppositeWindow	Window
WindowStateListener	windowStateChanged	WindowEvent getOldState getNewState	Window