绘图问题 - 从其他形状绘制复合形状

Question

所以我有一个大学作业。这个概念是我们要完成一些类层次结构的东西。基本上它可以让我们绘制不同的形状。

我可以成功绘制每个形状；我需要它在哪里，我需要它有多大，就像需要一样......我遇到麻烦的部分是这个复合层次结构。

基本上我们应该有一个名为Compound.java 的新类，并从该类扩展我们应该有其他三个类，House、tree 和earth；每个都应该采用我们创建的形状对象（矩形、正方形、直线、椭圆和圆形）并绘制所需的图片，如类名所示。

我遇到问题的地方是家庭课程；例如：我可以让它绘制一个矩形，但是当我试图让它绘制第二个矩形之后，它基本上忘记了第一个，只绘制第二个！

我们没有练习过 Graphics 的东西，所以我不知道我可以调用任何方法或任何东西来绘制然后在 House 构造函数中继续。

我明白为什么它会覆盖第一个矩形，当调用House 构造函数时，它会遍历构造函数中的所有内容，然后返回到Compound.java 并使用draw(Graphics g) 方法绘制它。 ...

但我不知道如何解决它！任何帮助将不胜感激......明天到期。

所有代码如下：

Shape.java：

import java.awt.*;

public abstract class Shape {
    int initX, initY;
    Color fillColour;

    public Shape() {
        initX = 0;
        initY = 0;
    }

    public Shape(int x, int y) {
        initX = x;
        initY = y;
    }

    public void setInitX (int x) {
        initX = x;
    }

    public void setInitY (int y) {
        initY = y;
    }

    public abstract void draw(Graphics g);
    public abstract double Area();
    public abstract double Perimeter();

    public void Move(int deltaX, int deltaY){
        //future work
    }

}

ClosedShape.java：

import java.awt.Graphics;

public abstract class ClosedShape extends Shape {
    boolean polygon;
    int numPoints;
    int[] xVertices;
    int[] yVertices;
    int x,y,width, height;

    public ClosedShape(boolean isPolygon, int numPoints) {
        super(0,0);
        this.polygon = isPolygon;
        this.numPoints = numPoints;
    }

    public ClosedShape(boolean isPolygon, int numPoints, int[] x, int[] y) {
        super(x[0],y[0]);
        this.polygon = isPolygon;
        if (isPolygon) {
            this.numPoints = numPoints;
            xVertices = new int[numPoints]; // error check?  if x.length == numPoints
            for (int i = 0; i < x.length; i++) { // make copy of array: why?
                xVertices[i] = x[i];
            }
            yVertices = new int[numPoints]; // error check?  if y.length == numPoints
            for (int i = 0; i < y.length; i++) { // make copy of array
                    yVertices[i] = y[i];
            }
        }
        else { // its an oval - define bounding box
            this.numPoints = 4;
            this.x = x[0];
            this.y = y[0];
            width = x[1];
            height = y[1];
        }
    }

    public void setXYCoords(int[] x, int[] y){
        this.xVertices = x;
        this.yVertices = y;
    }

    // Gives access to the width attribute
    public void setWidth(int width){
        this.width = width;
    }

    // Gives access to the height attribute
    public void setHeight(int height) {
        this.height = height;
    }

    public void draw(Graphics g) {
        if (polygon) {
            g.drawPolygon(xVertices, yVertices, numPoints);
        }
        else {
            g.drawOval(x, y, width, height);
        }

    }

    public abstract double Area();
    public abstract double Perimeter();








}

矩形.java：

public class Rectangle extends ClosedShape
{

    public Rectangle(int x, int y, int width, int height)
    {
        super(true, 4);

        setWidth(width);
        setHeight(height);

        int [] arrayX = new int[4];
        arrayX[0] = x;
        arrayX[1] = (x+width);
        arrayX[2] = (x+width);
        arrayX[3] = x;

        int [] arrayY = new int[4];
        arrayY[0] = y;
        arrayY[1] = y;
        arrayY[2] = y+height;
        arrayY[3] = y+height;

        setXYCoords(arrayX, arrayY);

    }

    public double Area()
    {
       return 0;
    }

    public double Perimeter()
    {
        return 0;
    }

}

Compound.java：

import java.awt.*;
import java.awt.Graphics;


public class Compound
{
    boolean polygon;
    int[] xVertices;
    int[] yVertices;
    int initX, initY;
    Color fillColour;

    public void setXYCoords(int[] x, int[] y)
    {
        this.xVertices = x;
        this.yVertices = y;
    }

    public void draw(Graphics g)
    {
        if (polygon) {
            g.drawPolygon(xVertices, yVertices, 4);
        }
        else {
            g.drawOval(1, 1, 1, 1);
        }

    }

}

House.java：

import java.awt.*;
import java.awt.Graphics;


public class House extends Compound
{

    public House(int x, int y, int width, int height)
    {

        int [] arrayX = new int[4];
        arrayX[0] = x;
        arrayX[1] = (x+width);
        arrayX[2] = (x+width);
        arrayX[3] = x;

        int [] arrayY = new int[4];
        arrayY[0] = y;
        arrayY[1] = y;
        arrayY[2] = y+height;
        arrayY[3] = y+height;

        setXYCoords(arrayX, arrayY);
        this.polygon = true;

        Rectangle house = new Rectangle(x, y, width, height);

        int [] arrayXTwo = new int[4];
        arrayXTwo[0] = x+(width/4);
        arrayXTwo[1] = x+(2*(width/4));
        arrayXTwo[2] = x+(2*(width/4));
        arrayXTwo[3] = x+(width/4);

        int [] arrayYTwo = new int[4];
        arrayYTwo[0] = y+(height/4);
        arrayYTwo[1] = y+(height/4);
        arrayYTwo[2] = y+height;
        arrayYTwo[3] = y+height;

        setXYCoords(arrayXTwo, arrayYTwo);
        this.polygon = true;

        Rectangle door = new Rectangle(x, y, width, height);

    }


}

Answer 1

从您的示例代码中，无法将任何形状“添加”到Compound 类。根据您的描述，Compound 应该是形状的“容器”。更多类似...

public class Compound
{
    private List<Shape> shapes;

    public Compound() {
        shapes = new ArrayList<Shape>(25);
    }

    public void addShape(Shape shape) {
        shapes.add(shape);
    }

    public Iterable<Shape> getShapes() {
        return shape;
    }

    public void draw(Graphics g) {
        for (Shape shape : shapes) {
            shape.draw(g);
        }
    }
}

现在您需要决定，最好将Color 与Shape 关联起来，是否应该为形状本身定义？这意味着您不能重复使用该形状。还是使用Compound 形状？