import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.image.MemoryImageSource;
import java.util.Random;
import javax.swing.JDialog;
import javax.swing.JPanel;
import javax.swing.Timer;
public class Rain extends JDialog implements ActionListener {
private Random random = new Random();
private Dimension screenSize;
private JPanel graphicsPanel;
//行高,列宽
private final static int gap = 20;
//存放雨点顶部的位置信息(marginTop)
private int[] posArr;
//行数
private int lines;
//列数
private int columns;
public Rain() {
initComponents();
}
private void initComponents() {
setLayout(new BorderLayout());
graphicsPanel = new GraphicsPanel();
add(graphicsPanel, BorderLayout.CENTER);
//设置光标不可见
Toolkit defaultToolkit = Toolkit.getDefaultToolkit();
Image image = defaultToolkit.createImage(new MemoryImageSource(0, 0, null, 0, 0));
Cursor invisibleCursor = defaultToolkit.createCustomCursor(image, new Point(0, 0), "cursor");
setCursor(invisibleCursor);
//ESC键退出
KeyPressListener keyPressListener = new KeyPressListener();
this.addKeyListener(keyPressListener);
//this.setAlwaysOnTop(true);
//去标题栏
this.setUndecorated(true);
//全屏
this.getGraphicsConfiguration().getDevice().setFullScreenWindow(this);
this.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
setVisible(true);
screenSize = Toolkit.getDefaultToolkit().getScreenSize();
lines = screenSize.height / gap;
columns = screenSize.width / gap;
posArr = new int[columns + 1];
random = new Random();
for (int i = 0; i < posArr.length; i++) {
posArr[i] = random.nextInt(lines);
}
//每秒10帧
new Timer(100, this).start();
}
/**
* @return 随机字符
*/
private char getChr() {
return (char) (random.nextInt(94) + 33);
}
@Override
public void actionPerformed(ActionEvent e) {
graphicsPanel.repaint();
}
private class GraphicsPanel extends JPanel {
@Override
public void paint(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
g2d.setFont(getFont().deriveFont(Font.BOLD));
g2d.setColor(Color.BLACK);
g2d.fillRect(0, 0, screenSize.width, screenSize.height);
//当前列
int currentColumn = 0;
for (int x = 0; x < screenSize.width; x += gap) {
int endPos = posArr[currentColumn];
g2d.setColor(Color.CYAN);
g2d.drawString(String.valueOf(getChr()), x, endPos * gap);
int cg = 0;
for (int j = endPos - 15; j < endPos; j++) {
//颜色渐变
cg += 20;
if (cg > 255) {
cg = 255;
}
g2d.setColor(new Color(0, cg, 0));
g2d.drawString(String.valueOf(getChr()), x, j * gap);
}
//每放完一帧，当前列上雨点的位置随机下移1~5行
posArr[currentColumn] += random.nextInt(5);
//当雨点位置超过屏幕高度时，重新产生一个随机位置
if (posArr[currentColumn] * gap > getHeight()) {
posArr[currentColumn] = random.nextInt(lines);
}
currentColumn++;
}
}
}
private class KeyPressListener extends KeyAdapter {
@Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_ESCAPE) {
System.exit(0);
}
}
}
public static void main(String[] args) {
new Rain();
}
}
