java - Java 弹跳球闪烁

Question

这个问题已经有答案了:

Something seems wrong with the layout, JButton showing unexpected behaviour at resize of the window (4 个回答)

已关闭 8 年前。

嗨，我的后台程序弹跳球有问题，问题是球闪烁，我不知道如何停止它:

类Graficos :

public class Graficos extends JFrame implements ActionListener {

    private JButton play, pause, exit;
    private Timer reloj;
    private Pelota pelota;
    private JPanel panel2, panel1;

    public Graficos(){
        super();
        reloj = new Timer(200, this);
        this.setLayout(new BorderLayout());
        pelota = new Pelota();
        play = new JButton("Play");
        play.setFont(new Font("ARIAL", Font.BOLD, 20));
        play.setBackground(Color.GREEN);
        play.setSize(20, 20);
        pause = new JButton("Pause");
        pause.setFont(new Font("ARIAL", Font.BOLD, 20));
        pause.setBackground(Color.ORANGE);
        pause.setSize(20, 20);
        exit = new JButton("Exit");
        exit.setFont(new Font("ARIAL", Font.BOLD, 20));
        exit.setBackground(Color.RED);
        exit.setSize(20, 20);
        panel1 = new JPanel();
        panel2 = new JPanel();
        panel2.setLayout(new GridLayout(1, 3));

        this.add(panel1, BorderLayout.CENTER);
        panel1.add(pelota, BorderLayout.CENTER);
        this.add(panel2, BorderLayout.SOUTH);
        panel2.add(play, BorderLayout.EAST);
        panel2.add(pause, BorderLayout.CENTER);
        panel2.add(exit, BorderLayout.WEST);

        this.setSize(440, 460);
        this.setVisible(true);

        reloj.start();

        play.addActionListener(this);
        pause.addActionListener(this);
        exit.addActionListener(this);
    }

    public void paint(Graphics g){
        super.paint(g);
        pelota.paintComponent(g);
        panel1.paintComponents(g);
    }

    public static void main(String args[]){
        Graficos x = new Graficos();
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        // TODO Auto-generated method stub

        if(e.getSource().equals(play))reloj.start();
        else{
            if(e.getSource().equals(pause))reloj.stop();
            else{
                if(e.getSource().equals(exit)){
                    reloj.stop();
                    System.exit(0);
                }
                else if(e.getSource().equals(reloj)){
                    pelota.muevete();
                    this.repaint();
                }
            }
        }
    }
}

类Pelota :

public class Pelota extends JPanel {

    private int x, y, dx=5, dy=5, ancho, alto;
    private ImageIcon foto, fondo;

    public Pelota(){

        x = 5;
        y = 5;
        fondo = new ImageIcon(getClass().getResource("genious.jpg"));
        foto = new ImageIcon(getClass().getResource("ball.png"));
        ancho = foto.getIconWidth();
        alto = foto.getIconHeight();
        this.setVisible(true);
        this.setSize(fondo.getIconWidth(), fondo.getIconHeight());
    }

    /*public void pintate(Graphics g){
        super.paint(g);
        g.drawImage(fondo.getImage(),0,0,null);
        g.drawImage(foto.getImage(),x,y,null);
    }
    */

    public void paintComponent(Graphics g) { 
         super.paintComponent(g); 
         g.drawImage(fondo.getImage(),0,0,this);
         g.drawImage(foto.getImage(),x,y,this);
         }

    public void muevete(){
        x += dx;
        y += dy;
        if(x+ancho >=fondo.getIconWidth()+30){
            dx *= -1;
        }
        if(y+alto >= fondo.getIconHeight()+40){
            dy *= -1;
        }
        if(x<=-40){
            dx *= -1;
        }
        if(y<=-10){
            dy *= -1;
        }
        //repaint();
    }

    public int getX() {
        return x;
    }

    public void setX(int x) {
        this.x = x;
    }

    public int getY() {
        return y;
    }

    public void setY(int y) {
        this.y = y;
    }

    public int getDx() {
        return dx;
    }

    public void setDx(int dx) {
        this.dx = dx;
    }

    public int getDy() {
        return dy;
    }

    public void setDy(int dy) {
        this.dy = dy;
    }

    public int getAncho() {
        return ancho;
    }

    public void setAncho(int ancho) {
        this.ancho = ancho;
    }

    public int getAlto() {
        return alto;
    }

    public void setAlto(int alto) {
        this.alto = alto;
    }

    public ImageIcon getFoto() {
        return foto;
    }

    public void setFoto(ImageIcon foto) {
        this.foto = foto;
    }

    public ImageIcon getFondo() {
        return fondo;
    }

    public void setFondo(ImageIcon fondo) {
        this.fondo = fondo;
    }
}

Answer 1

当你编写这个程序时，你到底在想什么？

public void paint(Graphics g){
    super.paint(g);
    pelota.paintComponent(g);
    panel1.paintComponents(g);
}

它彻底打破了油漆链。删除它以消除闪烁。

那么代码就会存在分层问题和透明度问题。我的猜测是面板需要以相反的顺序添加。例如。而不是:

pelota → panel1 → JFrame

..应该是..

panel1 → pelota → JFrame

最上面的面板需要是透明的。

作为更一般的建议:

1. 为了更快地获得更好的帮助，请发布 MCVE (最小完整可验证示例)。
2. 获取示例图像的一种方法是热链接到 this Q&A 中看到的图像。 .