Question

我无法使用方法重载将“乌龟”（实际上是三角形）的初始位置设置到屏幕上。我打算使用super关键字在新的Dynamicturtle构造函数中调用Turtle，然后从新的动态乌龟构造函数的新参数中设置乌龟的位置，然后绘制乌龟。给出了使用移动方法来实现这一目的的提示？

然后它将创建一个新的Dynamicturtle变量并在主类中实例化它，它会将乌龟绘制到JFrame。我完全坚持如何实现这一目标 - 这似乎是一个简单的问题。任何帮助将不胜感激。

主要课程。

import javax.swing.*;

class Lab5
{
	public static void main(String [ ] args)
	{
		JFrame frame = new JFrame();
		Canvas canvas = new Canvas();
		frame.setTitle("Hello Frame");
		frame.setSize(800, 600);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
		frame.add(canvas);
		int deltaTime = 20; // milliseconds
		// game loop
		
		Dyanmicturtle jig = new Dyanmicturtle(canvas, 400, 300);
		jig.drawTurtle();

		while(true)
		{
		Utils.pause(deltaTime);
		}
	}
}

DynamicTurtle类：

class DynamicTurle extends Turtle
{
	private int speed = 100;
	private int time;
	private double xPos, yPos;
	private CartesianCoordinate myLocation;
	private int Angle = 0;

	DynamicTurle(Canvas canvas, CartesianCoordinate initLocation)
	{
		super(canvas, initLocation);
		this.drawTurtle();
	}

	DynamicTurle(Canvas canvas, double xPosition, double yPosition) //THE PROBLEM CONSTRUCTOR 
	{
		super(canvas, newPosition);
		CartesianCoordinate newPosition = new CartesianCoordinate (this.xPosition, this.yPosition);			
		this.drawTurtle();
	}


	public int getSpeed()
	{
		return this.speed;
	}

	public void setSpeed(int speed)
	{
		this.speed = speed;
	}

	public void update(int time)
	{
		this.unDrawTurtle();
		this.move((speed*100/time));	
		this.drawTurtle();
	}
}

海龟类：

class Turtle 
{
    private Canvas canvas; // private field reference to a canvas private           
    private CartesianCoordinate myLocation, oldLocation; 
    private boolean penDown = true;
    private double Angle;
    public Turtle kieranMullen;

    public Turtle(Canvas canvas, CartesianCoordinate initLocation) 
    {
        this.canvas = canvas;
        this.myLocation = new CartesianCoordinate(0,0);
        Angle = 0;
        penDown = true;
        myLocation = initLocation.copy();        
    }

    public void putPenUp() 
    {
       this.penDown = false; 
    }

    public void putPenDown() 
    {
        this.penDown = true; 
    }   

    public void turn(double amount) 
    {
       Angle = Angle + amount; 
    }
    

    public void move(int pixels) 
    {
        double radians = Math.toRadians(Angle);
        double dx = pixels * Math.sin(radians);
        double dy = pixels * Math.cos(radians);
        
        CartesianCoordinate oldLocation = myLocation.copy();
        
        myLocation.add(dx,dy);
        
        if(penDown)
        {
            canvas.drawLineBetweenPoints(myLocation, oldLocation);
        }
    }

    public void drawTurtle()
    {
        this.putPenDown();
        this.turn(90);
        this.move(10);
        this.putPenDown();
        this.turn(240);
        this.move(20);
        this.putPenDown();
        this.turn(240);
        this.move(20);
        this.putPenDown();
        this.turn(240);
        this.move(10);
        this.turn(270);       
    }

    public void unDrawTurtle()
    {
        canvas.removeMostRecentLine();
        canvas.removeMostRecentLine();
        canvas.removeMostRecentLine();
        canvas.removeMostRecentLine();
    }

    public void showSquare()
    {
        this.unDrawTurtle();
        Utils.pause(1000);
        this.drawTurtle();
        Utils.pause(1000);
        this.unDrawTurtle();
        this.move(100);
        this.drawTurtle();
        Utils.pause(1000);
        this.unDrawTurtle();  
        this.turn(90);
        this.drawTurtle();
        Utils.pause(1000);
        this.unDrawTurtle();
        this.move(100);
        this.drawTurtle();
        Utils.pause(1000);
        this.unDrawTurtle();  
        this.turn(90);
        this.drawTurtle();
        Utils.pause(1000);
        this.unDrawTurtle();
        this.move(100);
        this.drawTurtle();
        Utils.pause(1000);
        this.unDrawTurtle();  
        this.turn(90);
        this.drawTurtle();
        Utils.pause(1000);
        this.unDrawTurtle();
        this.move(100);
        this.drawTurtle();
        Utils.pause(1000);
        this.unDrawTurtle();  
        this.turn(90);
        this.drawTurtle();
        Utils.pause(1000);
        this.unDrawTurtle();         
    }
}

谢谢你提前给出的任何帮助。

Answer 1

将构造函数更改为：

DynamicTurle(Canvas canvas, double xPosition, double yPosition) {
    super(canvas, new CartesianCoordinate (xPosition, yPosition));
    this.drawTurtle();
}

或者甚至更好，打电话给你的其他构造函数：

DynamicTurle(Canvas canvas, double xPosition, double yPosition) {
    this(canvas, new CartesianCoordinate (xPosition, yPosition));
}

这避免了重复的this.drawTurtle();

行

使用“super”关键字将初始位置设置为JFrame

1 个答案: