java - 如何修复java错误？

Question

所以我必须创建一个程序，在其中使用多态性和继承来创建指向左的箭头和箭头，我做到了。但是，当我创建主类并尝试调用这些方法时，例如“LeftArrow.drawHere”来绘制箭头，我收到错误消息，说我无法对 LeftArrow 类中的非静态字段“drawHere()”进行静态引用”。然后我想知道如果我不能这样做我该如何设计我的主要方法以便它绘制箭头？这是我的代码，请注意，有几个类，但我将在此处发布所有类。

import java.util.Scanner;

public class LeftArrow extends ShapeBasic
{
    private int tail, width;
    private static int inside;
    public LeftArrow()
    {
        super();
        tail = 0;
        width = 0;
    }
    public LeftArrow(int noff, int ntail, int nwidth)
    {
        super(noff);
        tail = ntail; 
        setWidth(nwidth);
    }

    public void setTail(int ntail)
    {
        tail = ntail;
    }

    public int getTail()
    {
        return tail;
    }
    public void setWidth(int nwidth)
    {
        if (nwidth % 2 == 1)
        {
            width = nwidth;
        }
        else
        {
            System.out.println(" Width must be odd");
            System.out.println("Enter a new width");
            Scanner key = new Scanner(System.in);
            int wid = key.nextInt();
            setWidth(wid);
        }
    }
    public int getWidth()
    {
        return width;
    }
    public void drawHere() 
    {
        drawTriangle();
        drawTail();
        drawBTriangle();
        //System.out.println();
    }
    public void drawTriangle()
    {
        inside = 1;
        int split = (width/2);
        skipSpaces(getOffset());
        System.out.println('*');
        for(int count = 0; count < split; count ++)
        {
            skipSpaces(getOffset() - (inside + 1));
            System.out.print('*');
            skipSpaces(inside);
            System.out.print('*');
            inside = inside + 2;
            System.out.println();
        }
    }
    public void drawTail()
    {
        skipSpaces(getOffset() - getInside() - 1);
        System.out.print('*');
        skipSpaces(getInside());
        for (int count = 0; count < tail ; count++)
        { 
            System.out.print('*');
        }
    }
    public void drawBTriangle()
    {
        int inside = getInside();
        int split = (width/2);
        System.out.println();
        for(int count = 0; count < split; count ++)
        {
            skipSpaces(getOffset() - (inside - 1));
            System.out.print('*');
            inside = inside - 2;
            skipSpaces(inside);
            System.out.print('*');
            System.out.println();
        }
        skipSpaces(getOffset());
        System.out.print('*');
    }
    public int getInside()
    {
        return inside;
    }
    private static void skipSpaces(int number)
    {
        for (int count = 0; count < number; count++)
            System.out.print(' ');
    }
    @Override
    public void setOffset(int noff) {
        // TODO Auto-generated method stub

    }
    @Override
    public int getOffset() {
        // TODO Auto-generated method stub
        return 0;
    }
}

import java.util.Scanner;

public class RightArrow extends ShapeBasic
{
    private int tail, width;
    private static int inside;
    public RightArrow()
    {
        super();
        tail = 0;
        width = 0;  
    }
    public RightArrow(int noff, int ntail, int nwidth)
    {
        super(noff);
        tail = ntail;
        setWidth(nwidth); // must be odd
    }
    public void setTail(int ntail)
    {
        tail = ntail;
    }
    public int getTail()
    {
        return tail;
    }
    public void setWidth(int nwidth)
    {
        if (nwidth % 2 == 1)
        {
            width = nwidth;
        }
        else
        {
            System.out.println(" Width must be odd");
            System.out.println("Enter a new width");
            Scanner key = new Scanner(System.in);
            int wid = key.nextInt();
            setWidth(wid);
        }
    }
    public int getWidth()
    {
        return width;
    }
    public void drawHere()
    {
        drawTriangle();
        drawTail();
        drawBTriangle();
        System.out.println();
    }
    public void drawTail()
    {
        skipSpaces(getOffset() + 1);
        for (int count = 0; count < tail ; count++)
        { 
            System.out.print('*');
        }
        skipSpaces(getInside());
        System.out.print('*');  // fix
    }
    public void drawTriangle()
    {
        inside = 1;
        int split = (width/2);
        skipSpaces(getOffset() + tail);
        System.out.println('*');
        for(int count = 0; count < split; count ++)
        {
            skipSpaces(getOffset() + tail);
            System.out.print('*');
            skipSpaces(inside);
            System.out.print('*');
            inside = inside + 2;
            System.out.println();
        }
    }
    public void drawBTriangle()
    {
        int inside = getInside();
        int split = (width/2);
        System.out.println();
        for(int count = 0; count < split; count ++)
        {
            skipSpaces(getOffset() + tail);
            System.out.print('*');
            inside = inside - 2;
            skipSpaces(inside);
            System.out.print('*');
            System.out.println();
        }
        skipSpaces(getOffset() + tail);
        System.out.print('*');
    }
    public int getInside()
    {
        return inside;
    }
    private static void skipSpaces(int number)
    {
        for (int count = 0; count < number; count++)
            System.out.print(' ');
    }
}

public abstract class ShapeBase implements ShapeInterface {
    private int offset;
    public abstract void drawHere();


    public void drawAt(int lineNumber) {
        for (int count = 0; count < lineNumber; count++)
            System.out.println();
        drawHere();
    }
}

public class ShapeBasic implements ShapeInterface
{

    private int offset;

    public ShapeBasic()
    {
        offset = 0;
    }
    public ShapeBasic( int noff)
    {
        offset = noff;
    }
    public void setOffset(int noff) 
    {
        offset = noff;
    }

    public int getOffset() 
    {
        return offset;
    }

    public void drawAt(int linnumber) 
    {
        for (int count = 0; count < linnumber; count++)
            System.out.println();
        drawHere();
    }

    public void drawHere() 
    {
        for (int count = 0; count < offset; count++)
            System.out.print(' ');
        System.out.println('*');
    }

}

public interface ShapeInterface 
{
    public void setOffset(int noff);    // set how many space from left

    public int getOffset(); // returns offset
    public void drawAt(int linnumber);  // moves down equal to line number Ex. 5 = 5 down
    public void drawHere(); // draws shape after moving left equal to offset
}

Answer 1

我想看看你的主要方法，但我没有声誉。据猜测，我想说也许您实际上并没有在主方法中实例化这些类的对象，而是尝试从中调用方法。例如，如果您这样做:

LeftArrow lArrow = new LeftArrow();
lArrow.drawHere();

它应该可以工作。