java - 重绘()不起作用

Question

当我尝试调用它时，重绘不起作用。它没有给出错误，看起来它只是忽略了整个函数。

这是我的代码:

public class Neerslag extends JComponent {
JPanel painting = new JPanel();
private int j = 0;

  Neerslag() {
    setPreferredSize(new Dimension(370, 200));
  }

  public void paintComponent(Graphics g) {
    super.paintComponent(g);

    g.setColor(Color.GRAY);

    g.fillOval(j, 20, 100, 20);
    g.fillOval(j + 10, 30, 100, 20);
    System.out.println("test2");

  }

  public void move(int j) {
    System.out.println("test");
    if (j < 50) {
        j++;
    } else {
        j = -j;
    }
    /*try {
        Thread.sleep(500);
    } catch (InterruptedException e) {
        System.err.println("sleep exception");
    }*/
    this.repaint();
  }

  public JPanel showPaint() {
    painting.add(new Neerslag());
    return painting;
  }

  public void Clear() {
    painting.repaint();
    System.out.println("hello");
  }
}

和

public class NeerslagFrame extends JFrame implements MouseListener {
NeerslagPanel panel1 = new NeerslagPanel();;
private int i=0;
Neerslag neerslag = new Neerslag();

public static void main(String[] args) {
    NeerslagFrame textFieldFrame = new NeerslagFrame();
    textFieldFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    textFieldFrame.setSize(500, 350);
    textFieldFrame.setVisible(true);

}

public NeerslagFrame(){
    super ("Neerslag");
    //panel1 = 
    this.addMouseListener(this);
    this.add(panel1.addSideBar(), BorderLayout.EAST);
    this.add(panel1.addSouthBar(), BorderLayout.SOUTH);
    this.add(neerslag.showPaint());
}
public void Clear(){
    //Neerslag paint = new Neerslag();
    this.add(new Neerslag());
}

@Override
public void mouseClicked(MouseEvent arg0) {
    neerslag.move(i);
    i++;
    neerslag.repaint();
    neerslag.revalidate();
    //this.add(neerslag.showPaint());
}
@Override
public void mouseEntered(MouseEvent arg0) {
    // TODO Auto-generated method stub

}
@Override
public void mouseExited(MouseEvent arg0) {
    // TODO Auto-generated method stub

}
@Override
public void mousePressed(MouseEvent arg0) {
    // TODO Auto-generated method stub

}
@Override
public void mouseReleased(MouseEvent arg0) {
    // TODO Auto-generated method stub

}


}

我错过了什么？它确实显示了最初的两个椭圆，但一旦我更改了“j”值，就不会重新绘制它们。预先感谢您!

Answer 1

repaint 并不是您真正想要的，您“似乎”想要的是 revalidate 和 repaint。

类似...

@Override
public void mouseClicked(MouseEvent arg0) {
    neerslag.move(i);
    i++;
    neerslag.revalidate();
    neerslag.repaint();
    this.add(neerslag.showPaint());
}

例如。

现在，就其值(value)而言，您的设计似乎是倒退的，也就是说，不是让 Neerslag 容器出现在其他容器中，而是将其自身的实例添加到其中，而是 Neerslag 应该只关心它自己而不关心其他任何事情。

您应该将painting面板移出并单独管理它，因为Neerslag根本不应该关心它 - 恕我直言