为什么这不是一个中心框架？[重复]

Question

为什么如果我将框架的宽度和高度设置为400，例如，可用空间较小，我如何围绕它工作，以及如何在不剪切内容的情况下将某些内容放在中心？例如

   public class Main extends JPanel{

    static int width = 400;
    static int height = 400;
    static int arcWidth = 400;
    static int arcHeight = 400;

    public static void main(String args[]){

        JFrame frame = new JFrame();
        JFrame mainContent = new JFrame();
        Main panel = new Main();
        frame.setSize(width, height);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setTitle("Clock");
        frame.add(panel);
        frame.setVisible(true);


    }

    public void paintComponent(Graphics g){
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;
        g2.setRenderingHint(
                RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);
        g.setColor(Color.BLACK);
        g2.setStroke(new BasicStroke(4,BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
        g.drawArc(width/2 -arcWidth/2, height/2 - arcHeight/2, arcWidth, arcHeight, 0, 360);
    }
}

Answer 1

首先使用“实际”值，而不是“神奇”值

getWidth和getHeight将告诉您组件的实际大小

@Override 
protected void paintComponent(Graphics g){
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D) g;
    g2.setRenderingHint(
            RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);
    g.setColor(Color.BLACK);
    g2.setStroke(new BasicStroke(4,BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
    g.drawArc(getWidth()/2 -arcWidth/2, getHeight()/2 - arcHeight/2, arcWidth, arcHeight, 0, 360);
}

至于你为什么有问题，请参阅：

• 我怎么能置身其中呢