学步园

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.RoundRectangle2D;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JToggleButton;
import javax.swing.SwingUtilities;
import javax.swing.Timer;


public class SwitchButton extends JToggleButton implements ActionListener {

    private static final int ARCNUMBER = 35;
    private int currentResolution = 50;
    private long cycleStart;
    private Timer timer = null;
    private final int MOVE_TIME = 2000;
    private int moveMinX;
    private int moveMaxX;
    private int buttonX;
    private ActionListener moveActionListener = new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {
            startTimer(currentResolution);
        }
    };

    public SwitchButton() {
        setBorder(null);
        addActionListener(moveActionListener);
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;
        Color oldColor = g2.getColor();
        g2.setColor(Color.WHITE);
        g2.fillRect(0, 0, getWidth(), getHeight());
        g2.setColor(oldColor);

        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);
        Shape backgroundShape = new RoundRectangle2D.Float(1, 1, getWidth() - 2, getHeight() - 2, ARCNUMBER, ARCNUMBER);

        boolean selected = getModel().isSelected();
        //fill shape
        Paint paint = null;
        if (selected) {
            paint = new GradientPaint(0, 0, new Color(45, 106, 169), 0, getHeight(), new Color(135, 183, 245));
        } else {
            paint = new GradientPaint(0, 0, new Color(144, 144, 144), 0, getHeight(), new Color(244, 244, 244));
        }
        g2.setPaint(paint);
        g2.fill(backgroundShape);
        //draw shape bounds
        g2.setColor(Color.DARK_GRAY);
        g2.draw(backgroundShape);

        JLabel onLabel = new JLabel("ON");
        JLabel offLabel = new JLabel("OFF");
        Dimension labelSize;
        //draw text.  off/on
        if (selected) {
            oldColor = g2.getColor();
            g2.setColor(Color.WHITE);
            labelSize = onLabel.getPreferredSize();
            g2.drawString(onLabel.getText(), getWidth() / 2 / 2 - labelSize.width / 2, getHeight() / 2 + labelSize.height / 2);
            g2.setColor(oldColor);
        } else {
            oldColor = g2.getColor();
            g2.setColor(Color.BLACK);
            labelSize = offLabel.getPreferredSize();
            g2.drawString(offLabel.getText(), getWidth() / 2 + labelSize.width / 2, getHeight() / 2 + labelSize.height / 2);
            g2.setColor(oldColor);
        }
        //draw button
        int buttonY = 0;
        int buttonWidth = getWidth() / 2;
        int buttonHeight = getHeight();
        Shape buttonShape = new RoundRectangle2D.Float(buttonX, buttonY, buttonWidth, buttonHeight, ARCNUMBER, ARCNUMBER);
        paint = new GradientPaint(0, 0, new Color(244, 244, 244), 0, getHeight(), new Color(144, 144, 144));
        g2.setPaint(paint);
        g2.fill(buttonShape);
        g2.setColor(new Color(140, 140, 140));
        g2.draw(buttonShape);
    }

    public static void main(String[] args) {
        SwitchButton button = new SwitchButton();
        button.setBounds(60, 10, 100, 30);

        JPanel mainPane = new JPanel();
        mainPane.setOpaque(true);
        mainPane.setBackground(Color.WHITE);
        mainPane.setLayout(null);
        mainPane.add(button);

        final JFrame frame = new JFrame();
        frame.setTitle("SwitchButton Demo");
        frame.setLayout(new BorderLayout());
        frame.getContentPane().add(mainPane, BorderLayout.CENTER);
        frame.setSize(233, 80);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                frame.setVisible(true);
            }
        });
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        long currentTime = System.nanoTime() / 1000000;
        long totalTime = currentTime - cycleStart;

        if (totalTime > MOVE_TIME) {
            cycleStart = currentTime;
        }
        float fraction = (float) totalTime / MOVE_TIME;
        fraction = Math.min(1.0f, fraction);
        fraction = 1 - Math.abs(1 - (2 * fraction));
        animate(fraction);
    }

    public void animate(float fraction) {
        float animationFactor = (float) Math.sin(fraction * (float) Math.PI / 2);
        animationFactor = Math.min(animationFactor, 1.0f);
        animationFactor = Math.max(animationFactor, 0.0f);
        buttonX = moveMinX + (int) (.5f + animationFactor * (float) (moveMaxX - moveMinX));
        if (isSelected()) {
            if (buttonX >= moveMaxX) {
                timer.stop();
                timer.setInitialDelay(100);
                buttonX = getWidth() / 2 - 1;
            }
        } else {
            if (buttonX - 1 <= moveMaxX) {
                timer.stop();
                timer.setInitialDelay(100);
                buttonX = 0;
            }
        }
        repaint();
    }

    private void startTimer(int resolution) {
        if (timer == null) {
            timer = new Timer(resolution, this);
        }
        if (!timer.isRunning()) {
            if (isSelected()) {
                moveMinX = 0;
                moveMaxX = getWidth() / 2 - 1;
            } else {
                moveMinX = getWidth() / 2 - 1;
                moveMaxX = 0;
            }
            timer.start();
        }

    }
}