最大化 JFrame 期间发生 Java 绘制错误

Question

我已按照代码在 JFrame 中进行绘制。

package march_2013;

import java.awt.Graphics;
import javax.swing.JFrame;

public class Question7 extends JFrame {

    public void paint(Graphics g) {
        int[] x = new int[] { 10, 60, 360, 410, 210, 210, 260, 210, 190, 160,
                190, 190 };
        int[] y = new int[] { 200, 250, 250, 200, 200, 180, 180, 100, 100, 160,
                160, 200 };
        g.drawPolygon(x, y, x.length);
        g.drawLine(190, 100, 190, 180);
        g.drawLine(210, 100, 210, 180);
    }

    public static void main(String[] args) {
        Question7 window = new Question7();
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.setBounds(440, 40, 420, 400);
        window.setVisible(true);
    }
}

它工作正常，给出以下输出。

但是我最大化了 JFrame，图像被重新绘制。但旧形象仍保持原样。

如何解决这个问题？谢谢!

Answer 1

调用super.paint()。

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

API document of paint说:

If this method is reimplemented, super.paint(g) should be called so that lightweight components are properly rendered.

要确保背景为白色:

public void paint(Graphics g) {
    super.paint(g);
    g.setColor(Color.WHITE);
    g.fillRect(0, 0, getWidth(), getHeight());
    g.setColor(Color.BLACK);
    // ...