java canvas画布事件

[java]代码库

import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class MyCanvas implements KeyListener, MouseListener {
	Canvas c; // 声明一个画布对象
	String s = "";

	public static void main(String args[]) {
		Frame f = new Frame("Canvas");
		MyCanvas mc = new MyCanvas();
		mc.c = new Canvas();
		f.add("Center", mc.c);

		f.setSize(150, 150);
		mc.c.addMouseListener(mc); // 注册监听器
		mc.c.addKeyListener(mc); // 注册监听器
		f.setVisible(true);
	}

	public void mouseClicked(MouseEvent ev) {
		System.out.println("MouseClicked");
		c.requestFocus();// 获得焦点，表示该窗口将接收用户的键盘和鼠标输入
	}

	public void keyTyped(KeyEvent ev) {
		System.out.println("KeyTyped");
		s += ev.getKeyChar(); // 获取每个输入的字符，依次添加到字符串s中
		c.getGraphics().drawString(s, 0, 20); // 显示字符串s
	}

	public void keyPressed(KeyEvent ev) {
		System.out.println("KeyPressed");
	}

	public void keyReleased(KeyEvent ev) {
		System.out.println("KeyReleased");
	}

	public void mousePressed(MouseEvent ev) {
		System.out.println("MousePressed");
	}

	public void mouseReleased(MouseEvent ev) {
		System.out.println("MouseReleased");
	}

	public void mouseEntered(MouseEvent ev) {
		System.out.println("MouseEntered");
	}

	public void mouseExited(MouseEvent ev) {
		System.out.println("MouseExited");
	}
}