java layer用法_Java Swing - 如何使用JProgressBar创建JLayer

import java.awt.BorderLayout;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.GridLayout;

import java.awt.Image;

import java.awt.event.ActionEvent;

import java.awt.image.BufferedImage;

import java.awt.image.FilteredImageSource;

import java.awt.image.RGBImageFilter;

import javax.swing.AbstractAction;

import javax.swing.BoundedRangeModel;

import javax.swing.DefaultBoundedRangeModel;

import javax.swing.JButton;

import javax.swing.JComponent;

import javax.swing.JFrame;

import javax.swing.JLayer;

import javax.swing.JPanel;

import javax.swing.JProgressBar;

import javax.swing.WindowConstants;

import javax.swing.plaf.LayerUI;

public class Main {

public static void main(String[] args) {

BoundedRangeModel model = new DefaultBoundedRangeModel();

BlockedColorLayerUI layerUI = new BlockedColorLayerUI();

JPanel p = new JPanel(new GridLayout(2, 1, 12, 12));

p.add(new JLayer(new JProgressBar(model), layerUI));

JPanel box = new JPanel();

box.add(new JButton(new AbstractAction("+10") {

private int i = 0;

@Override

public void actionPerformed(ActionEvent e) {

model.setValue(i = (i >= 100) ? 0 : i + 10);

}

}));

p.repaint();

JPanel panel = new JPanel(new BorderLayout());

panel.add(p, BorderLayout.NORTH);

panel.add(box, BorderLayout.SOUTH);

JFrame f = new JFrame();

f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

f.getContentPane().add(panel);

f.setSize(320, 240);

f.setVisible(true);

}

}

class BlockedColorLayerUI extends LayerUI {

BufferedImage bi;

int prevw, prevh;

@Override

public void paint(Graphics g, JComponent c) {

JLayer jlayer = (JLayer) c;

JProgressBar progress = (JProgressBar) jlayer.getView();

int w = progress.getSize().width;

int h = progress.getSize().height;

if (bi == null || w != prevw || h != prevh) {

bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);

}

prevw = w;

prevh = h;

Graphics2D g2 = bi.createGraphics();

super.paint(g2, c);

g2.dispose();

Image image = c.createImage(new FilteredImageSource(bi.getSource(),

new RedGreenChannelSwapFilter()));

g.drawImage(image, 0, 0, c);

}

}

class RedGreenChannelSwapFilter extends RGBImageFilter {

@Override

public int filterRGB(int x, int y, int argb) {

int r = (int) ((argb >> 16) & 0xff);

int g = (int) ((argb >> 8) & 0xff);

int b = (int) ((argb) & 0xff);

return (argb & 0xff000000) | (g << 16) | (r << 8) | (b);

}

}