布局管理器OverlayLayout实现PhotoShop工具面板效果

 final JTextField x1 = new JTextField("0.0", 4); // Button1 x alignment
        final JTextField y1 = new JTextField("0.0", 4); // Button1 y alignment
        final JTextField x2 = new JTextField("0.0", 4);
        final JTextField y2 = new JTextField("0.0", 4);
        final JTextField x3 = new JTextField("0.0", 4);
        final JTextField y3 = new JTextField("0.0", 4);

        p2.add(x1);
        p2.add(y1);
        p2.add(x2);
        p2.add(y2);
        p2.add(x3);
        p2.add(y3);

        GridBagConstraints constraints = new GridBagConstraints();
        c.add(p1, constraints);

        constraints.gridx = 1;
        JButton updateButton = new JButton("Update");
        updateButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
                jb1.setAlignmentX(
                    Float.valueOf(x1.getText().trim()).floatValue());
                jb1.setAlignmentY(
                    Float.valueOf(y1.getText().trim()).floatValue());
                jb2.setAlignmentX(
                    Float.valueOf(x2.getText().trim()).floatValue());
                jb2.setAlignmentY(
                    Float.valueOf(y2.getText().trim()).floatValue());
                jb3.setAlignmentX(
                    Float.valueOf(x3.getText().trim()).floatValue());
                jb3.setAlignmentY(
                    Float.valueOf(y3.getText().trim()).floatValue());

                p1.revalidate();
            }
        });
        c.add(updateButton, constraints);

        constraints.gridx = 0;
        constraints.gridy = 1;
        constraints.gridwidth = 2;
        c.add(p2, constraints);
    }

    public static void main(String args[]) {
        OverlayTest ot = new OverlayTest();
        ot.setVisible(true);
    }

    public class SimpleReporter implements ActionListener {
        public void actionPerformed(ActionEvent ae) {
            System.out.println(ae.getActionCommand());
        }
    }

    public class GridPanel extends JPanel {
        public void paint(Graphics g) {
            super.paint(g);
            int w = getSize().width;
            int h = getSize().height;
            g.setColor(Color.red);
            g.drawRect(0,0,w-1,h-1);
            g.drawLine(w/2,0,w/2,h);
            g.drawLine(0,h/2,w,h/2);
        }
    }
}

最后提醒，使用OverlayLayout布局管理器关键要记住X，Y轴对应组件位置，和容器没有关系。只要明白这一点，使用还是很简单方便的，我用OverlayLayout布局管理器clone了一个PhotoShop的工具面板。