Java适配器类 _Java适配器类

本文概述

java.awt.event适配器类
java.awt.dnd适配器类
javax.swing.event适配器类
Java WindowAdapter示例
Java MouseAdapter示例
Java MouseMotionAdapter示例
Java KeyAdapter示例

Java适配器类提供了侦听器接口的默认实现。如果继承适配器类, 则不会被迫提供所有侦听器接口方法的实现。因此, 它节省了代码。
适配器类可在java.awt.event, java.awt.dnd和javax.swing.event包中找到。适配器类及其相应的侦听器接口如下所示。
java.awt.event适配器类

适配器类	侦听器界面
WindowAdapter	WindowListener
KeyAdapter	KeyListener
MouseAdapter	MouseListener
MouseMotionAdapter	MouseMotionListener
FocusAdapter	FocusListener
ComponentAdapter	ComponentListener
ContainerAdapter	ContainerListener
HierarchyBoundsAdapter	HierarchyBoundsListener

java.awt.dnd适配器类

适配器类	侦听器界面
DragSourceAdapter	DragSourceListener
DragTargetAdapter	DragTargetListener

javax.swing.event适配器类

适配器类	侦听器界面
MouseInputAdapter	MouseInputListener
InternalFrameAdapter	InternalFrameListener

Java WindowAdapter示例

import java.awt.*; import java.awt.event.*; public class AdapterExample{ Frame f; AdapterExample(){ f=new Frame("Window Adapter"); f.addWindowListener(new WindowAdapter(){ public void windowClosing(WindowEvent e) { f.dispose(); } }); f.setSize(400, 400); f.setLayout(null); f.setVisible(true); } public static void main(String[] args) { new AdapterExample(); } }

输出：

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Java MouseAdapter示例

import java.awt.*; import java.awt.event.*; public class MouseAdapterExample extends MouseAdapter{ Frame f; MouseAdapterExample(){ f=new Frame("Mouse Adapter"); f.addMouseListener(this); f.setSize(300, 300); f.setLayout(null); f.setVisible(true); } public void mouseClicked(MouseEvent e) { Graphics g=f.getGraphics(); g.setColor(Color.BLUE); g.fillOval(e.getX(), e.getY(), 30, 30); } public static void main(String[] args) { new MouseAdapterExample(); } }

输出：

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Java MouseMotionAdapter示例

import java.awt.*; import java.awt.event.*; public class MouseMotionAdapterExample extends MouseMotionAdapter{ Frame f; MouseMotionAdapterExample(){ f=new Frame("Mouse Motion Adapter"); f.addMouseMotionListener(this); f.setSize(300, 300); f.setLayout(null); f.setVisible(true); } public void mouseDragged(MouseEvent e) { Graphics g=f.getGraphics(); g.setColor(Color.ORANGE); g.fillOval(e.getX(), e.getY(), 20, 20); } public static void main(String[] args) { new MouseMotionAdapterExample(); } }

【Java适配器类】输出：

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Java KeyAdapter示例

import java.awt.*; import java.awt.event.*; public class KeyAdapterExample extends KeyAdapter{ Label l; TextArea area; Frame f; KeyAdapterExample(){ f=new Frame("Key Adapter"); l=new Label(); l.setBounds(20, 50, 200, 20); area=new TextArea(); area.setBounds(20, 80, 300, 300); area.addKeyListener(this); f.add(l); f.add(area); f.setSize(400, 400); f.setLayout(null); f.setVisible(true); } public void keyReleased(KeyEvent e) { String text=area.getText(); String words[]=text.split("\\s"); l.setText("Words: "+words.length+" Characters:"+text.length()); } public static void main(String[] args) { new KeyAdapterExample(); } }

输出：