任何实现了Runnable接口的类都可以创建线程。这是为了弥补JAVA中单继承的特性。
同样的例子我们使用对Runnable接口的实现进行重写，三部曲：创建一个实现Runnable接口的类的实例，创建和其联系的线程，启动线程。
public class RunnableDemo1 implements Runnable
{
String name;
int count;
int delay;
public static void main(String arg[]) {
RunnableDemo1 one = new RunnableDemo1("one",1000,2);
//Thread类的定义是Thread(Runnable runnable)，而且Thread类本身也实现了Runnable接口
Thread threadOne = new Thread(one);//注意要用Thread类创建一个线程类
threadOne.start();
RunnableDemo1 two = new RunnableDemo1("two",2000,5);
Thread threadTwo = new Thread(two);
threadTwo.start();
}
RunnableDemo1(String nameString,int countStart,int seconds) {
name = nameString;
count = countStart;
delay = seconds * 1000;
}
public void run() {
while(true) {
try {
System.out.println(name + ": " + count++);
Thread.sleep(delay);
} catch(InterruptedException e) {
return;
}
}
}
}
弹球动画：
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Color;
import java.awt.Canvas;
import java.awt.Container;
import java.awt.Rectangle;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JFrame;
public class RunnableDemo2 extends JFrame {
public static void main(String arg[]) {
new RunnableDemo2();
}
public RunnableDemo2() {
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e)
{ System.exit(0); } } );
Container container = getContentPane();
BounceBallCanvas canvas = new BounceBallCanvas();
container.add(canvas);
pack();
canvas.start();
setLocation(250,100);
setVisible(true);
}
}
class BounceBallCanvas extends Canvas implements Runnable {
private double y;
private double x;
private final static int diameter = 10;
private final static double gravity = 0.3;
private double velocity;
private Rectangle rect;
private int width;
private int height;
private Image image = null;
private boolean running;
private Thread looper;
private int bounceCount;
BounceBallCanvas() {
rect = null;
setSize(100,300);
running = false;
height = 0;
width = 0;
}
public void start() {
if(!running) {
running = true;
looper = new Thread(this);
looper.start();
}
}
public void stop() {
running = false;
}
public void run() {
try {
while(running) {
Thread.sleep(33);
repaint();
}
} catch(Exception e) {
System.out.println(e.getStackTrace());
}
}
public void update(Graphics g) {
rect = getBounds(rect);
if((height != rect.height) || (rect.width != width)) {
height = rect.height;
width = rect.width;
velocity = 0.0;
bounceCount = 0;
x = width / 2;
y = 0;
image = createImage(rect.width,rect.height);
}
if(velocity > 0.0) {
if(((int)(y) + diameter) > rect.height) {
velocity = -velocity;
velocity *= 0.95;
y = (double)(rect.height - diameter);
if(++bounceCount > 20) {
y = 0;
velocity = 0.0;
bounceCount = 0;
}
}
}
velocity += gravity;
y += velocity;
paint(image.getGraphics());
g.drawImage(image,0,0,this);
}
public void paint(Graphics g) {
if(rect == null)
return;
g.setColor(Color.white);
g.fillRect(0,0,rect.width,rect.height);
g.setColor(Color.black);
g.fillOval((int)x,(int)y,diameter,diameter);
}
}
最新评论