Question

抱歉，这可能是一个非常基本的问题，但我有一个名为butterfly的类，其代码用于绘制蝴蝶对象，如下所示：

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.BasicStroke;

public class butterfly extends JPanel {
public butterfly() {
}
     public void draw(Graphics2D g2){
    //the width of the oval. A petal is an oval.

    //TODO: Your code goes IN HERE (not in main), ALL OF IT. Replace the code below.

    //draw one oval of length 300pixels from center to edge
    g2.setColor(Color.blue);
    g2.fillOval(500,55, 70, 70);
    g2.fillOval(450, 40, 70, 70);
    g2.fillOval(460,100, 40, 40);
    g2.fillOval(495, 110, 40, 40);


    g2.setColor(Color.black);
    g2.setStroke(new BasicStroke(13));

    g2.drawLine(520, 50, 490, 150);

 }

}

然后我尝试将它放在这个组件中，这样我就可以放入更多的物体，但它甚至不会画出蝴蝶？

import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class RippingOffofAmy extends JComponent
{

    private butterfly yay;

    public RippingOffofAmy()
    {
        yay = new butterfly();
    }

    public void paintComponent(Graphics g)
    {
        Graphics2D g2 = (Graphics2D) g;

       //checks to see if rectangle has moves 100 places yet
       //if has, then adds new obstacle and resets count
       yay.draw(g2);

        //draws obstacle and avatar
    }

}

为什么呢？（忽略我使用我的一些朋友代码的类名和评论）如果我遗漏了某些东西，那么某人可以真正具体地说明要添加什么，这对我来说非常糟糕，谢谢！

Answer 1

您应该阅读一些教程，但这是您尝试做的。

以下是我要做的事情：

package de;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;

import javax.swing.*;

@SuppressWarnings("serial")
public class Butterfly extends JPanel {
@Override
public void paint(Graphics g){
    super.paint(g);
    Graphics2D g2d = (Graphics2D) g;
    g2d.setColor(Color.blue);
    g2d.fillOval(500,55, 70, 70);
    g2d.fillOval(450, 40, 70, 70);
    g2d.fillOval(460,100, 40, 40);
    g2d.fillOval(495, 110, 40, 40);


    g2d.setColor(Color.black);
    g2d.setStroke(new BasicStroke(13));

    g2d.drawLine(520, 50, 490, 150);
}

}

简要说明：创建一个JFrame（这是窗口本身）覆盖JPanel的痛苦功能将butterfly的代码输入pain函数创造一个蝴蝶＆＃39;（扩展JPanel）将蝴蝶添加到JFrame 运行程序：）

为什么Component没有绘制任何东西？

1 个答案: