将值传递给 class

Question

我正在尝试使用 java.awt.Point 将 x 和 y 坐标传递给 class 中的构造函数。我的 main class 抛出一个错误，说“构造函数 Quadrilateral(int, int, int, int, int, int, int, int) 未定义。我想在传递给我的构造函数时 'public Quadrilateral(Point... points)' 我可以将坐标作为一个简单的列表传递。谁能告诉我这几行代码可能哪里出错了？

主要

import java.awt.Point;


    public class QuadrilateralTest
    {
        public static void main(String[] args)
        {
            Quadrilateral quadrilateral = new Quadrilateral(1, 1, 6, 2, 6, 9, 2, 7);
System.out.printf("%s %s %s %s %s\n", quadrilateral);
        }
    }

四边形class

import java.awt.Point;


public class Quadrilateral
{
    //points contain x and y coordinates
    private Point point1;
    private Point point2;
    private Point point3;
    private Point point4;


    public Quadrilateral(Point... points)
    {
        point1 = new Point(1, 2);
        point2 = new Point(3, 4);
        point3 = new Point(5, 6);
        point4 = new Point(7, 8);       
    }

    //setters and getters
    public Point getPoint1()
    {
        return point1;
    }

    public Point getPoint2()
    {
        return point2;
    }

    public Point getPoint3()
    {
        return point3;
    }

    public Point getPoint4()
    {
        return point4;
    }

    public String toString()
    {
         return ("\nThe Points of the Quadrilateral are:\n " +
                getPoint1() +"," + getPoint2() +"," + getPoint3() + "," + getPoint4())+"\n";
    }

}

Answer 1

您的构造函数接收 varargs 个 Point - 您不能只传入一堆 int。尝试实例化 Point 并将它们传入。

Answer 2

你的代码根本没有意义，你有 varargs Points 参数，但没有在构造函数中使用它们，如果你不需要输入参数，你可以用无参数构造函数替换它

 public Quadrilateral()
    {
        point1 = new Point(1, 2);
        point2 = new Point(3, 4);
        point3 = new Point(5, 6);
        point4 = new Point(7, 8);       
    }

并在 main()

中做

Quadrilateral quadrilateral = new Quadrilateral();

如果你真的想要传递和使用参数作为可变参数Point，让你的构造函数使用参数的值：-

public Quadrilateral(Point... points){

if((points.length>0)&&(points[0]!=null)){ //make sure to check this condition to allow user to input any number of parameters
point1=points[0];
}

if((points.length>1)&&(points[1]!=null)){
point2=points[1];
}
.
.
}

然后你可以在main()中写：-

Point point1 =new Point(1,2);
Point point2 =new Point(1,2);
Quadrilateral quad=new Quadrilateral(point1,point2);

Answer 3

您的代码可以按照@Evan 的建议进行修复，如下所示：

public Quadrilateral(Point... points)
{
    point1 = points[0];
    point2 = points[1];
    point3 = points[2];
    point4 = points[3];       
}

但是正如你所理解的那样会有很多问题。

如果您恰好需要 4 个点，正如我们在您的构造函数中看到的那样，您根本不应该使用 varargs。你应该只得到 4 个不同的 Point 参数。

public Quadrilateral(Point _point1, Point _point2, Point _point3, Point _point4)
{
    point1 = _point1;
    point2 = _point2;
    point3 = _point3;
    point4 = _point4;       
}

这样您将强制用户发送恰好 4 Points。

将值传递给 class

Pass values to class

java

awt