Question

谢谢你我终于让按钮正常工作但现在我不得不制作我刚创建的形状以保持在屏幕上。每次我点击创建新形状时，我选择另一个我刚创建的形状消失。我看看自定义油漆，但仍然混淆

public class ShapeStamps extends JFrame {

    Random numGen = new Random();
    public int x;
    public int y;
    private JPanel mousePanel, Bpanel;
    private JButton circle, square, rectangle, oval;
    private int choice = 0;

    public ShapeStamps() {

        super("Shape Stamps");
        Bpanel = new JPanel();
        circle = new JButton("Circle");           
        square = new JButton("Square");           
        rectangle = new JButton("Rectangle");
        oval = new JButton("Oval");

        circle.addActionListener(
                new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                choice = 1;
            }
        });
        square.addActionListener(
                new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                choice = 2;
            }
        });
        rectangle.addActionListener(
                new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                choice = 3;
            }
        });
        oval.addActionListener(
                new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                choice = 4;
            }
        });
        mousePanel = new JPanel();
        mousePanel.setBackground(Color.WHITE);
        MouseHandler handler = new MouseHandler();
        setVisible(true);
        addMouseListener(handler);
        addMouseMotionListener(handler);
        add(mousePanel);
        Bpanel.add(circle);
        Bpanel.add(square);
        Bpanel.add(rectangle);
        Bpanel.add(oval);

        add(Bpanel, BorderLayout.SOUTH);

        setSize(500, 500);
        setVisible(true);
    }

    private class MouseHandler extends MouseAdapter implements
            MouseMotionListener {

        public void mousePressed(MouseEvent e) {
            x = e.getX();
            y = e.getY();

            repaint();
        }
    }

    public void paint(Graphics g) {
        super.paintComponents(g);

        setBounds(0, 0, 500, 500);
        Graphics2D g2d = (Graphics2D) g;

        if (choice == 0) {
            g2d.setFont(new Font("Serif", Font.BOLD, 32));
            g2d.drawString("Shape Stamper!", 150, 220);
            g2d.setFont(new Font("Serif", Font.ITALIC, 16));
            g2d.drawString("Programmed by: None", 150, 245);
        }
        if (choice == 1) {

            Color randomColor1 = new Color(numGen.nextInt(256), numGen.nextInt(256), numGen.nextInt(256));
            g2d.setPaint(randomColor1);
            g2d.drawOval(x - 50, y - 50, 100, 100);
        }
        if (choice == 2) {

            Color randomColor2 = new Color(numGen.nextInt(256), numGen.nextInt(256), numGen.nextInt(256));
            g2d.setPaint(randomColor2);

            g2d.drawRect(x - 50, y - 50, 100, 100);
        }
        if (choice == 3) {
            Color randomColor2 = new Color(numGen.nextInt(256), numGen.nextInt(256), numGen.nextInt(256));
            g2d.setPaint(randomColor2);
            g2d.draw(new Rectangle2D.Double(x - 75, y - 50, 150, 100));
        }
        if (choice == 4) {
            Color randomColor2 = new Color(numGen.nextInt(256), numGen.nextInt(256), numGen.nextInt(256));
            g2d.setPaint(randomColor2);
            g2d.draw(new Ellipse2D.Double(x - 50, y - 25, 100, 50));
        }
    }
}

Answer 1

每次重新绘制JFrame时，它都会经历绘图过程，当你在屏幕上标记某些内容时，你必须拥有一个数据结构来保存标记的“对象”。这样，每次调用绘图过程时，它都会在正确的位置重新绘制对象（也许颜色随你决定改变它）

按钮不会显示，并且在创建新按钮时，形状会保持消失

1 个答案: