java - 如何使JFrame内JPanel内JLabel内的BufferedImage正确刷新？

Question

这是我的代码:

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.swing.*;

public class FlatShadingDemo {

static BufferedImage myPicture;
static JLabel pic;
static int width = 800;
static int height = 450;
static Random r = new Random();

private static void initialise() {
    JFrame frame = new JFrame("Flat shading demo");

    JPanel layout = new JPanel();
    layout.setLayout(new BoxLayout(layout,BoxLayout.Y_AXIS));
    frame.getContentPane().add(layout);

    myPicture = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

    pic = new JLabel(new ImageIcon(myPicture));

    JButton button = new JButton("Refresh");
    button.addActionListener( 
            new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                    render();
                }
            }
    );

    layout.add(pic);
    layout.add(button);

    frame.pack();
    frame.setVisible(true);
}

public static void main(String[] args) {
    initialise();

    render();

}

public static void render() {
    for (int y = 0; y < height; y++) {
        for (int x = 0; x < width; x++) {
            myPicture.setRGB(x, y, new Color(r.nextInt(256),r.nextInt(128),r.nextInt(25)).getRGB());
        }
    }
}
}

当我运行它时，会生成并显示图像。当我单击“刷新”时，在调整窗口大小之前不会发生任何情况。我需要刷新 myPicture、pic、layout 和frame 中的哪一个，其函数名称是什么？我对 Swing 和图形完全陌生，因此我们将不胜感激。

Answer 1

更改:

public void actionPerformed(ActionEvent e) {
    render();
}

致:

public void actionPerformed(ActionEvent e) {
    render();
    pic.repaint();
}

Component.repaint()的详细信息是:

Repaints this component.

If this component is a lightweight component, this method causes a call to this component's paint method as soon as possible. Otherwise, this method causes a call to this component's update method as soon as possible.