java - 使用 ArrayList 绘图时遇到问题

Question

我在从我创建的 ArrayList 中绘制组件时遇到了一些问题。如果我搞砸了，我要么得到第一个元素，要么得到第二个元素，如果我幸运的话，两者都不会出现!

import java.awt.*;
import java.awt.geom.*;
import java.util.*;
import javax.swing.*;

public class FaceShortCode {
ArrayList<CreateCircles> faceCircles = new ArrayList<CreateCircles>();

public FaceShortCode() {
    JFrame main = new JFrame();
    main.setTitle("Face Frame");
    main.setSize(new Dimension(600, 600));
    main.setLocationRelativeTo(null);
    main.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    main.setVisible(true);

    Container c = main.getContentPane();
    // c.setLayout(null);

    faceCircles.add(0, new CreateCircles(100, 50, 400, 350, Color.red));
    faceCircles.add(1, new CreateCircles(200, 100, 65, 65, Color.black));
    c.add(faceCircles.get(0));
    c.add(faceCircles.get(1));

}

class CreateCircles extends JComponent {
    double x, y, width, height;
    Color myColor;

    public CreateCircles(double x, double y, double width, double height,
            Color myColor) {
        this.x = x;
        this.y = y;
        this.width = width;
        this.height = height;
        this.myColor = myColor;
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;
        Ellipse2D circle = new Ellipse2D.Double(x, y, width, height);
        g2.setColor(myColor);
        g2.fill(circle);

    }
}

static class Run {
    public static void main(String[] args) {
        new FaceShortCode();
    }
}

}

我尝试在每次添加到容器 c 后添加一个 main.repaint() ，在我的绘画方法中尝试了一个 repaint() 但似乎没有任何效果。还有其他东西可以放置我刚刚缺少的 repaint() 吗？

Answer 1

您需要将所有逻辑放在 setVisible() 之前，否则您的框架将在执行逻辑之前变得可见。

public FaceShortCode() {

    Container c = main.getContentPane();
    // c.setLayout(null);

    faceCircles.add(0, new CreateCircles(100, 50, 400, 350, Color.red));
    faceCircles.add(1, new CreateCircles(200, 100, 65, 65, Color.black));
    c.add(faceCircles.get(0));
    c.add(faceCircles.get(1));

    JFrame main = new JFrame();

    main.setTitle("Face Frame");
    main.setSize(new Dimension(600, 600));
    main.setLocationRelativeTo(null);
    main.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    main.setVisible(true);
}

考虑使 FaceShortCode 扩展 JFrame。

public class FaceShortCode extends JFrame {
    private ArrayList<CreateCircles> faceCircles = new ArrayList<CreateCircles>();

    public FaceShortCode {
        setLayout(new Girdlayout(1, 2));

        faceCircles.add(0, new CreateCircles(100, 50, 400, 350, Color.red));
        faceCircles.add(1, new CreateCircles(200, 100, 65, 65, Color.black));

        add(faceCircles.get(0));
        add(faceCircles.get(1))

        setTitle("Face Frame");
        setSize(new Dimension(600, 600));
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);
    }
}