如何在我的小行星计划中展示我的宇宙飞船？

Question

我正在尝试完成一个 Asteroid 项目。我有四节课。小行星、多边形、游戏和小行星。 我正在制造一艘新的船，它是船的一个子类。我是java新手。我试图制作一个新的船对象，但我无法让它出现在屏幕上。 https://docs.oracle.com/javase/7/docs/api/java/awt/Graphics.html 但是，在船级中，我使用了 fillPolygon 现在它显示在屏幕上。但我知道写法。 我如何使用船舶对象制作船舶并使其出现。我在下面提供我的课程。

 package asteroids;

/*
CLASS: Asteroids
DESCRIPTION: Extending Game, Asteroids is all in the paint method.
NOTE: This class is the metaphorical "main method" of your program,
   it is your control center.
Original code by Dan Leyzberg and Art Simon
*/
import java.awt.*;
import java.awt.event.*;

class Asteroids extends Game {
   static int counter = 0;

public Asteroids() {
  super("Asteroids!",800,600);
  this.setFocusable(true);
  this.requestFocus();
 }

public void paint(Graphics brush) {
    brush.setColor(Color.black);
    brush.fillRect(0,0,width,height);

    // sample code for printing message for debugging
    // counter is incremented and this message printed
    // each time the canvas is repainted
    counter++;
    brush.setColor(Color.white);
    brush.drawString("Counter is " + counter,10,10);
    ship p = new ship(
            new Point[] {new Point(1,1),new Point(3,1),new Point(1.5,2)},
            new Point(3,3),
            0);


    brush.setColor(Color.red);
    p.paint(brush );

 }

public static void main (String[] args) {
    Asteroids a = new Asteroids();

    a.repaint();










   }
}  

多边形类

enter code herepackage asteroids;

/*

类：多边形 描述：多边形是由一组定义的空间中的点序列 这样的点，偏移量和旋转。偏移量是 形状的原点和中心之间的距离。 旋转以度为单位测量，0-360。 用法：你打算用一组点来实例化这个类 永远定义它的形状，然后通过重新定位和修改它 旋转那个形状。在定义形状时，相对位置 使用您提供的点数，换句话说：{(0,1),(1,1),(1,0)} 与 {(9,10),(10,10),(10,9)} 的形状相同。

class Polygon {
  private Point[] shape;   // An array of points.
  public Point position;   // The offset mentioned above.
  public double rotation; // Zero degrees is due east.

 public Polygon(Point[] inShape, Point inPosition, double inRotation) {
    shape = inShape;
    position = inPosition;
    rotation = inRotation;

   // First, we find the shape's top-most left-most boundary, its origin.
    Point origin = shape[0].clone();
    for (Point p : shape) {
  if (p.x < origin.x) origin.x = p.x;
  if (p.y < origin.y) origin.y = p.y;
 }

// Then, we orient all of its points relative to the real origin.
   for (Point p : shape) {
     p.x -= origin.x;
     p.y -= origin.y;
  }
}


  // "getPoints" applies the rotation and offset to the shape of the polygon.
   public Point[] getPoints() {
   Point center = findCenter();
   Point[] points = new Point[shape.length];
    for (int i = 0; i < shape.length; i++) {
    for (Point p : shape) {
      Point p = shape[i];
       double x = ((p.x-center.x) * Math.cos(Math.toRadians(rotation)))
           - ((p.y-center.y) * Math.sin(Math.toRadians(rotation)))
           + center.x/2 + position.x;
  double y = ((p.x-center.x) * Math.sin(Math.toRadians(rotation)))
           + ((p.y-center.y) * Math.cos(Math.toRadians(rotation)))
           + center.y/2 + position.y;
  points[i] = new Point(x,y);
  }
  return points;
 }

  // "contains" implements some magical math (i.e. the ray-casting algorithm).
 public boolean contains(Point point) {
  Point[] points = getPoints();
  double crossingNumber = 0;
   for (int i = 0, j = 1; i < shape.length; i++, j=(j+1)%shape.length) {
    if ((((points[i].x < point.x) && (point.x <= points[j].x)) ||
       ((points[j].x < point.x) && (point.x <= points[i].x))) &&
      (point.y > points[i].y + (points[j].y-points[i].y)/
       (points[j].x - points[i].x) * (point.x - points[i].x))) {
    crossingNumber++;
  }
 }
return crossingNumber%2 == 1;
}

 public void rotate(int degrees) {rotation = (rotation+degrees)%360;}

 /*
 The following methods are private access restricted because, as this access
 level always implies, they are intended for use only as helpers of the
 methods in this class that are not private. They can't be used anywhere else.
 */

 // "findArea" implements some more magic math.
 private double findArea() {
   double sum = 0;
    for (int i = 0, j = 1; i < shape.length; i++, j=(j+1)%shape.length) {
    sum += shape[i].x*shape[j].y-shape[j].x*shape[i].y;
  }
  return Math.abs(sum/2);
  }

 // "findCenter" implements another bit of math.
 private Point findCenter() {
  Point sum = new Point(0,0);
   for (int i = 0, j = 1; i < shape.length; i++, j=(j+1)%shape.length) {
     sum.x += (shape[i].x + shape[j].x)
           * (shape[i].x * shape[j].y - shape[j].x * shape[i].y);
    sum.y += (shape[i].y + shape[j].y)
           * (shape[i].x * shape[j].y - shape[j].x * shape[i].y);
   }
    double area = findArea();
   return new Point(Math.abs(sum.x/(6*area)),Math.abs(sum.y/(6*area)));
 }

} 级船 包装小行星；

import java.awt.Color;
import java.awt.Graphics;

public class ship extends Polygon{
  static int counter=0;

   public ship(Point[] inShape, Point inPosition, double inRotation) {
       super(inShape, inPosition, inRotation);
        // TODO Auto-generated constructor stub
   }

   public void paint(Graphics brush) {
        brush.fillPolygon(new int []{400,380,380,420,420,400},new int[]    {300,320,360,360,320,300},6); 

 }


public void drawPolygon(Point[] points, Point point, int i) {
    // TODO Auto-generated method stub

}

}

 Any help will be appreciated ,thanks

Answer 1

小行星应直接或间接（通过游戏）扩展 JFrame。

实例化应该扩展 JFrame 的 Asteroids 类后，请执行以下操作：

asteroid.setVisible(true);

将出现一个新的 jpanel，您的绘画方法将在该 jpanel 的画布上绘画。