GUI图形编程（6）---事件

事件的概念

事件处理是界面处理的基本功能，当用户点击鼠标或者按下键盘时，Swing界面上获得焦点的组件都会收到一个事件通知，这个事件通知是Swing体系内部发出的，界面就会根据收到的事件通知，做出相应的处理，比如弹出对话框或者读取用户输入。

Java Swing事件处理模型

                                     事件源  ；   注册事件监听器   ；  事件监听器

事件处理流程

（1）明确事件源。所有的图形界面组件对象都可以成为事件源对象。如何确定某一组件是事件源对象？动作发生在哪一个组件上，那么该组件就是一个事件源对象。

（2）为事件源添加事件监听方法。监听器方法根据发送的动作来确定。假设发生一个鼠标点击的动作，那么要给事件源添加鼠标的监听器方法。

（3）事件处理。自定义事件处理类，实现对应的接口，实现该接口的抽象方法

package org.lanqiao.loginui;

import java.awt.Cursor;
import java.awt.Image;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.util.Map;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;

public class LoginUI {
	JFrame loginFrame;
	JPanel loginPanel;
	JTextField username;
	JPasswordField password;
	JLabel  codeImg = new JLabel();
	private String uname;
	private String pw;
	JButton bt = new JButton("按钮");
	public LoginUI() {
		loginFrame = new JFrame();
		loginPanel = new JPanel();//使用空布局
	
		username = new JTextField();
		password = new JPasswordField();
	}
	public void init() {
		loginFrame.setSize(650, 400);
		loginFrame.setIconImage(new ImageIcon("image/title.gif").getImage());
		loginFrame.setLocationRelativeTo(null);
		loginFrame.setResizable(false);
		loginFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		loginPanel = new LoginPanel("image/login1.jpg");
		loginPanel.setLayout(null);
		
		
		username.setBounds(390, 157, 192, 25);
		password.setBounds(390, 191, 192, 25);
		bt.setBounds(300, 120, 120, 25);
		Map<String,Object> codeAndPic = CodeUtil.generateCodeAndPic();
		codeImg.setIcon(new ImageIcon((Image)codeAndPic.get("codePic")));
		codeImg.setBounds(502, 235, 90, 20);
		loginPanel.add(codeImg);
		loginPanel.add(bt);
		loginPanel.add(username);
		loginPanel.add(password);
		loginFrame.add(loginPanel);
		loginFrame.setVisible(true);
		//当鼠标移动进入登陆按钮区域时，改变鼠标的形状
		loginFrame.addMouseMotionListener(new MouseMotionListener() {
			
			@Override
			public void mouseMoved(MouseEvent e) {
				int x = e.getX();//获取鼠标当前所处位置的x坐标
				int  y = e.getY();
				if(x > 397  && x < 504 && y > 308 && y < 336) {
					Cursor c = new Cursor(Cursor.HAND_CURSOR);
					loginFrame.setCursor(c);
				}else {
					loginFrame.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
				}
				
				
					
			}
			
			@Override
			public void mouseDragged(MouseEvent e) {
				// TODO Auto-generated method stub
				
			}
		});
		//当鼠标进入到登陆按钮区域时，监听鼠标单击事件
		loginFrame.addMouseListener(new MouseAdapter() {
			/*
			 * 鼠标单击事件
			 * @see java.awt.event.MouseListener#mouseClicked(java.awt.event.MouseEvent)
			 */
			@Override
			public void mouseClicked(MouseEvent e) {
				uname = username.getText();
				pw = new String(password.getPassword());
				int x = e.getX();//获取鼠标当前所处位置的x坐标
				int  y = e.getY();
				if(x > 397  && x < 504 && y > 308 && y < 336) {
					String loginRes = 	new LoginController().login(uname, pw);
					if("用户名密码为空".equals(loginRes)) {
						JOptionPane.showMessageDialog(loginFrame, "用户名或密码不能为空","Inane warning",
							    JOptionPane.WARNING_MESSAGE);
					}else if("用户名密码有误".equals(loginRes)) {
						
						JOptionPane.showMessageDialog(loginFrame, "用户名密码有误","Inane warning",
							    JOptionPane.WARNING_MESSAGE);
					}
					else {
						JOptionPane.showMessageDialog(loginFrame, "登陆成功","Inane warning",
							    JOptionPane.WARNING_MESSAGE);
						loginFrame.setVisible(false);
					}
				}
			}
		});
		bt.addMouseListener(new MouseAction());
		username.addFocusListener(new FocusAdapter() {
			@Override
			public void focusLost(FocusEvent e) {
				System.out.println(username.getText());
			}
		});
		password.addKeyListener(new KeyListener() {
			
			@Override
			public void keyTyped(KeyEvent e) {
				// TODO Auto-generated method stub
				
			}
			
			@Override
			public void keyReleased(KeyEvent e) {
				/*int keyCode = e.getKeyCode();
				
				String keyText  = e.getKeyText(keyCode);
				System.out.println(keyCode+"----"+keyText);*/
				//当按下的a键的时候，输出"你好"
				if(KeyEvent.VK_A == e.getKeyCode()) {
					System.out.println("你好");
				}
			}
			
			@Override
			public void keyPressed(KeyEvent e) {
				// TODO Auto-generated method stub
				
			}
		});
	}
	public static void main(String[] args) {
		LoginUI ui = new LoginUI();
		ui.init();
		
	}
	
	
}
class  MouseAction extends MouseAdapter{
	
	@Override
	public void mouseClicked(MouseEvent e) {
		System.out.println("按钮被点击了");
	}
}