小编Kur*_*t16的帖子

当我写"new Triangle();"时,我得到这个错误"没有封闭的oppgave1类型的实例可访问".我需要帮助来解释一下我做错了什么(关于三角类).我是java的新开始.谢谢你的进步.

public static void main(String[] args) {

    Triangle T1 = new Triangle(1, 1, 1, "green", false);

    Scanner input = new Scanner(System.in);
    System.out.println("Enter three sides of the triangle: ");
    double side1 = input.nextInt();
    double side2 = input.nextInt();
    double side3 = input.nextInt();
    System.out.println("Enter a color: ");
    String color = input.nextLine();
    System.out.println("Enter true or false (to indicate triangle is filled or no): ");
    String isFilled = input.nextLine();
}

public class GeometricObject {
    //Data fields
    private String color = "blue";
    private boolean filled; …

我正在尝试编写一个关于弹跳球的代码,但我仍然坚持如何让球反弹.代码似乎是正确的,没有来自eclipse的错误消息,但球不动.任何帮助/提示都很感激.

这是我的代码:

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

public class BouncingBallTest extends JFrame {

    private JButton jbtStart = new JButton("Start");
    private JButton jbtStop = new JButton("Stop");
    private Ball canvas = new Ball();

    public BouncingBallTest() {
        JPanel panel = new JPanel(); // Use the panel to group buttons
        panel.add(jbtStart);
        panel.add(jbtStop);

        add(canvas, BorderLayout.CENTER); // Add canvas to centre
        add(panel, BorderLayout.SOUTH); // Add panel to south

        // register listener
        jbtStart.addActionListener(new StartBouncingBallTest());
        jbtStop.addActionListener(new StopBouncingBallTest());

    }

    // the main method
    public static void main(String[] args) …