绘图问题 - 从其他形状绘制复合形状

Question

所以我有一个大学的作业。这个概念是我们要完成一些类层次结构的东西。基本上这是让我们画出不同形状的东西。

我可以成功绘制每个形状;我需要它的地方，以及我需要多大的地方，就像需要的一样......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叫做Compound.java和新类的，我们应该有其他三类，House，tree和earth延伸;其中每一个都应该采用我们创建的形状对象（矩形，方形，线条，椭圆形和圆形）并绘制所需的图片，如类名所示。

我遇到问题的地方在于家庭课堂;例如：我可以绘制一个矩形，但是当我尝试绘制第二个矩形之后，它基本上忘记了第一个矩形，并且只绘制了第二个矩形！

我们还没有任何与图形的东西练习，所以我不知道任何方法或任何我可以调用绘制然后继续在House构造函数。

我明白为什么它会覆盖第一个矩形，当House构造函数被调用，它通过在构造函数中所有的东西运行，然后返回到Compound.java和使用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......明天将到期。

这里的所有代码：

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(); 








} 

Rectangle.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

从你的示例代码，也没有办法，要 “增加” 任何形状的Compound类。根据你的描述，Compound应该是形状的“容器”。东西沿线的更多...

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); 
     } 
    } 
} 

现在你需要决定，它在哪里最好关联的Color与Shape应该它本身的形状来定义？这意味着你不能重用形状。或者与Compound形状？