Question

因此，我创建了一个程序，在文本框中接受圆的半径，在随机点中创建随机颜色的圆，并使用另一个按钮清除所有圆的页面。我遇到的问题是我的被覆盖的paint（）。

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.Random;


public class PushPanel extends JPanel
{
    private JButton newb;
    private JButton clear;
    private JLabel label;
    private int x, y, width, r;
    private int color;
    private JTextField radius;

    public PushPanel()
    {
        newb = new JButton("New");
        clear = new JButton("Clear");
        radius = new JTextField(5);

        radius.addActionListener(new TextListener());
        newb.addActionListener(new ButtonListener());
        clear.addActionListener(new ButtonListener2());

        label = new JLabel ("Circle creator", SwingConstants.CENTER);

        add(radius);
        add (newb);
        add (clear);
        add(label);

        setPreferredSize(new Dimension(300,300));

    }


    public class ButtonListener implements ActionListener
    {
        public void actionPerformed(ActionEvent event)
        {
            paintComponent(getGraphics());
        }

        public void paintComponent(Graphics page)
        {
             Random rand = new Random();   
             int redValue = rand.nextInt(255); 
             int greenValue = rand.nextInt(255); 
            int blueValue = rand.nextInt(255); 
            Color clr = new Color(redValue, greenValue, blueValue);

            Random generator = new Random(101);
             x = generator.nextInt();
             y = generator.nextInt();
             width = r*2;

            page.setColor(clr);
            page.fillOval(x,y,width,width);
        }


    }

    public class ButtonListener2 implements ActionListener
    {
        public void actionPerformed(ActionEvent event)
        {
            paintComponent(getGraphics());
        }

        public void paintComponent(Graphics page)
        {
            page.setColor(Color.white);
        }
    }

    public class TextListener implements ActionListener
    {
        public void actionPerformed(ActionEvent event)
        {
            String text = radius.getText();
            r = Integer.parseInt(text);

        }
    }
}


This is the driver class, pretty basic

    public class Circle 
{

    public static void main(String[] args) 
    {

        JFrame frame = new JFrame("Circle stuff");
        frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);

        PushPanel panel = new PushPanel();

        frame.getContentPane().add(panel);
        frame.pack();
        frame.setVisible(true);
    }

}

Answer 1

你实际上没有告诉我们问题是什么，但我敢打赌，因为你的paintComponent（）方法在你的ButtonListener类中，而不是你的PushPanel类。

此外，除非你真的知道自己在做什么，否则你永远不应该在组件上调用getGraphics（）。推荐阅读：http://docs.oracle.com/javase/tutorial/uiswing/painting/

绘画到面板

1 个答案: