Java学习记录 事件监听篇
键盘事件
Class KeyEvent
java.lang.Object
java.util.EventObject
java.awt.AWTEvent
java.awt.event.ComponentEvent
java.awt.event.InputEvent
java.awt.event.KeyEvent
KeyEvent类 键盘监听类，KeyListener接口也可实现处理事件监听
KeyListener接口有3个抽象方法，分为不同的敲击方式
keyTyped(KeyEvent e); 点击
KeyPressed(keyEvent e); 被按下（未松也触发）
KeyReleased(keyEvent e); 松开释放
方法自查API
注意：KeyEvent类中以“VK_”为前缀的静态常量代表键盘的keyCode（键盘按键
import javax.swing.*;
import java.awt.*;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
public class KeyEventTest extends JFrame {
private JTextField jtf = new JTextField(3);
private JLabel jl = new JLabel("H");
private Container container = getContentPane();
public KeyEventTest(){
setBounds(400, 300, 90, 80);
setDefaultCloseOperation(3);
jtf.setFont(new Font("微软雅黑",Font.PLAIN,16));
jl.setFont(new Font("微软雅黑",Font.PLAIN,16));
//窗体流布局
container.setLayout(new FlowLayout());
//添加组件
container.add(jtf);
container.add(jl);
jtf.addKeyListener(new KeyListener() {
@Override
public void keyTyped(KeyEvent e) {
System.out.println("点击了键盘");
}
@Override
public void keyPressed(KeyEvent e) {
System.out.println(e.getKeyText(e.getKeyCode()));
}
@Override
public void keyReleased(KeyEvent e) {
jtf.setText("");
jl.setText(e.getKeyText(e.getKeyCode()));
}
});
setVisible(true);
}
public static void main(String[] args) {
new KeyEventTest();
}
}
鼠标事件
Class MouseEvent
java.lang.Object
java.util.EventObject
java.awt.AWTEvent
java.awt.event.ComponentEvent
java.awt.event.InputEvent
java.awt.event.MouseEvent
MouseEvent类 键盘监听类，MouseListener接口也可实现处理事件监听
MouseListener接口有5个抽象方法，分为不同的触发方式
mouseEntered(MouseEvent e); 鼠标移入组件触发\
mousePressed(MouseEvent e); 鼠标按下触发
mouseReleased(MouseEvent e); 鼠标释放触发
mouseClicked(MouseEvent e); 鼠标单击触发
mouseExited(MouseEvent e); 鼠标移出组件触发
方法自查API
MouseEvent类静态常量
| 静态常量 | 值 | 键 |
|---|---|---|
| BUTTON1 | 1 | 鼠标左键 |
| BUTTON2 | 2 | 鼠标滚轮 |
| BUTTON3 | 3 | 鼠标右键 |
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
public class MouseEventTest extends JFrame implements MouseListener {
private Container c = getContentPane();
private JButton jb = new JButton("清空测试");
private JLabel jl = new JLabel("H");
private JTextArea jta = new JTextArea(15,35);
private JScrollPane jsp = new JScrollPane(jta);
private String scr = "";
private static String tap = "(暂无)";
public MouseEventTest(){
setLayout(new FlowLayout());
setDefaultCloseOperation(3);
setBounds(400, 300, 400, 330);
//边框颜色
jsp.setBorder(BorderFactory.createLineBorder(Color.RED));
c.add(jb);
c.add(jl);
c.add(jsp);
//添加监听器
jb.addMouseListener(this);
jta.addMouseListener(this);
jb.addActionListener(new AbstractAction() {
@Override
public void actionPerformed(ActionEvent e) {
jta.setText("");
}
});
setVisible(true);
}
//鼠标移入组件
@Override
public void mouseEntered(MouseEvent e) {
if (e.getSource() == jb){
scr = "按钮：";
}
if (e.getSource() == jta){
scr = "文本框：";
}
jl.setText(scr+"移入组件");
}
//鼠标移出组件
@Override
public void mouseExited(MouseEvent e){
jl.setText(scr+"移出组件");
}
//鼠标释放
@Override
public void mouseReleased(MouseEvent e){
annpanduan(e);
jl.setText(scr+"松开"+tap);
jta.append(scr+"松开"+tap+"\n");
}
//鼠标按下
@Override
public void mousePressed(MouseEvent e){
annpanduan(e);
jl.setText(scr+"按下"+tap);
jta.append(scr+"按下"+tap+"\n");
}
//鼠标单击
@Override
public void mouseClicked(MouseEvent e){
annpanduan(e);
jl.setText(scr+"单击"+tap);
jta.append(scr+"单击"+tap+"\n");
}
public static void annpanduan(MouseEvent e){
int source = e.getButton();
switch(source){
case 1 : tap = "(左键)"; break;
case 2 : tap = "(中键)"; break;
case 3 : tap = "(右键)"; break;
}
}
public static void main(String[] args) {
new MouseEventTest();
}
}
窗体事件
窗体焦点事件
WindowFocusListener接口，捕获当前窗体焦点变化
抽象方法
windowGainedFocus(WindowEvent e); 获取焦点触发
windowLosetFocus(WindowEvent e); 失去焦点触发
import javax.swing.*;
import java.awt.event.WindowEvent;
import java.awt.event.WindowFocusListener;
public class WindowFocusTest extends JFrame implements WindowFocusListener {
public WindowFocusTest(){
setBounds(400,300,400,300);
setDefaultCloseOperation(3);
//为窗体添加焦点事件
addWindowFocusListener(this);
setVisible(true);
}
@Override
public void windowGainedFocus(WindowEvent e){
//获取焦点
System.out.println("获取焦点");
}
@Override
public void windowLostFocus(WindowEvent e){
//失去焦点
System.out.println("失去焦点");
}
public static void main(String[] args) {
new WindowFocusTest();
}
}
窗体状态事件
WindowStateListener接口，捕获当前窗体正常、最大、最小化的变化
抽象方法
windowStateChanged(WindowEvent e); 窗体发生变化时触发
窗体状态变化后，获取状态的方法
（int）getNewState() 获取窗体 现在 的状态
（int）getOldState() 获取窗体 以前 的状态
窗体状态的静态常量
| 静态常量 | 值 | 键 |
|---|---|---|
| NORMAL | 0 | 正常化 |
| ICONIFIED | 1 | 最小化 |
| MAXIMIZED_BOTH | 6 | 最大化 |
import javax.swing.*;
import java.awt.event.WindowEvent;
import java.awt.event.WindowFocusListener;
import java.awt.event.WindowStateListener;
public class WindowBasicTest extends JFrame implements WindowFocusListener, WindowStateListener {
public WindowBasicTest(){
setBounds(400,300,400,300);
setDefaultCloseOperation(3);
//为窗体添加焦点事件
addWindowFocusListener(this);
addWindowStateListener(this);
setVisible(true);
}
@Override
public void windowGainedFocus(WindowEvent e){
//获取焦点
System.out.println("获取焦点");
}
@Override
public void windowLostFocus(WindowEvent e){
//失去焦点
System.out.println("失去焦点");
}
@Override
public void windowStateChanged(WindowEvent e){
//窗体发生变化
//原旧状态 --> 新状态
System.out.println(VaryString(e.getOldState())+" --> "+VaryString(e.getNewState()));
}
public String VaryString(int e){
String scr = null;
switch(e){
case 0: scr = "正常化";break;
case 1: scr = "最小化";break;
case 6: scr = "最大化";break;
default: scr = "最小化";break;
}
return scr;
}
public static void main(String[] args) {
new WindowBasicTest();
}
}
其他窗体事件
WindowListener接口，捕获窗体的变化情况
抽象方法
windowActivated(WindowEvent e); 激活触发（类似焦点
windowDeactivated(WindowEvent e); 非激活触发
windowIconified(WindowEvent e); 最小化触发
windowDeiconified(WindowEvent e); 非最小化触发
windowOpened(WindowEvent e); 窗口打开触发
windowClosing(WindowEvent e); 关闭窗口触发
windowClosed(WindowEvent e); 已关闭窗口触发
选项事件
Class ItemEvent
java.lang.Object
java.util.EventObject
java.awt.AWTEvent
java.awt.event.ItemEvent
ItemEvent类 选项监听类，ItemListener接口也可实现处理事件监听
抽象方法
itemStateChanged(ItemEvent e); 选定/取消 时触发
处理选项方法
（object）getItem() 获取选中对象
（int）getStateChange() 获取选中的状态
getStateChange()方法 返回的静态常量
| 静态常量 | 值 | 键 |
|---|---|---|
| SELECTED | 1 | 选中 |
| DESELECTED | 2 | 取消 |
import javax.swing.*;
import java.awt.*;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
public class OptionEventTest extends JFrame implements ItemListener {
private String[] listdata = {
"全部", "复选框", "单选按钮"};
private JComboBox jcblist = new JComboBox(listdata);
//选中内容
private JPanel jpl = new JPanel();
private JRadioButton jrb = new JRadioButton("单选按钮");
private JCheckBox jcb = new JCheckBox("复选框");
private Container c = getContentPane();
public OptionEventTest() {
setBounds(400, 300, 200, 140);
setDefaultCloseOperation(3);
jpl.add(jrb);
jpl.add(jcb);
jpl.setSize(200, 280);
jpl.setBorder(BorderFactory.createTitledBorder("显示区"));
c.add(jcblist, BorderLayout.NORTH);
c.add(jpl, BorderLayout.CENTER);
//监听
jrb.addItemListener(this);
jcb.addItemListener(this);
jcblist.addItemListener(new ItemListener() {
@Override
public void itemStateChanged(ItemEvent e) {
switch ((String) e.getItem()) {
case "单选按钮":
jrb.setVisible(true);
jcb.setVisible(false);
break;
case "复选框":
jrb.setVisible(false);
jcb.setVisible(true);
break;
default:
jrb.setVisible(true);
jcb.setVisible(true);
break;
}
}
});
setVisible(true);
}
@Override
public void itemStateChanged(ItemEvent e) {
// 选中 ro 取消
//单选按钮和复选框的父类
JToggleButton tmp = (JToggleButton) e.getSource();
String type = tmp.getText();
switch (e.getStateChange()) {
case 1:
System.out.println("选中" + type);
break;
case 2:
System.out.println("取消" + type);
break;
default:
System.out.println("错误");
break;
}
}
public static void main(String[] args) {
new OptionEventTest();
}
}
