如何在java </shape>中创建ArrayList <shape>的对象

Question

我想创建一个ArrayList Shape的新对象。 ArrayList包含形状，矩形，椭圆等... ArrayList<Shape> shapes = new ArrayList<Shape>(); 新对象必须包含它所包含的形状以及用于命名形状的文本属性。这就是我想要实现的目标：

我该怎么做？

EDITED

这就是我想说的

我到达了这里！现在我希望java把它写成＆＃34;学生与ID＆＃34;

相关联

Answer 1

1。创建界面Shape -

interface Shape {

}  

2。现在每个形状 - 矩形，椭圆等都可以实现Shape界面 -

Rectangle implements Shape{
 String name;
 // other properties as required

  //constructor as your requirement
  //getters setters as your requirement
}

或 -

Ellipse implements Shape{
     String name;
     // other properties as required

     //constructor as your requirement
     //getters setters as your requirement

    }

3。现在创建ArrayList Shape -

ArrayList<Shape> shapes = new ArrayList<Shape>)();

由于Rectangle和Ellipse都实现Shape，ArrayList形状可以包含两种类型的对象。之后你可以写 -

Rectangle r = new Rectangle();
Ellipse e = new Ellipse();
shapes.add(r);
shapes.add(e);  

希望它会有所帮助 非常感谢。

Answer 2

public class NamedShape {
    private String name;
    private Shape shape;
    public NamedShape( String name, Shape shape ){
        this.name = name;
        this.shape = shape;
    }
    public String getName(){ return name; }
    public Shape getShape(){ return shape; }
}

现在您可以创建List<NamedShape>等。

List<NamedShape> shapes = new ArrayList<>();
shapes.add( new NamedShape( "Humpty-Dumpty",
                            new Ellipse2D.Double( x, y, w, h ) ) );
shapes.add( new NamedShape( "John Doe",
                            new Rectangle2D.Double( u, v, a, b ) ) );

或者你迭代你拥有的List<Shape>并添加名称：

for( Shape shape: myUnnamedShapes ){
    shapes.add( new NamedShape( inventName(), shape ) );
}

稍后要画画，

for (NamedShape s : shapes) { 
    graphSettings.setPaint(strokeCounter.next()); 
    graphSettings.draw(s.getShape()); 
}