Question

我试图在Processing中创建游戏。基本上是它的乒乓球。我有3节课。主要类（PongRunner），球类（PongBall）和球拍类（PongRacket）。

我正在尝试在PongRunner类中显示PongRacket对象但是，它不会显示。这是我的代码：

PongRacket课程：

    // this is the class for the pong racket used in the game
    // it specifies the racket's attributes and methods

    public class PongRacket{

      // attributes of the pong racket
      private int racketWidth = (1/9)*width; // width of the racket
      private int racketHeight = (1/15)*height; // height of the racket
      private int startRacketXPosition = (4/9)*width; // x value for starting position of racket
      private int startRacketYPosition = (14/15)*height; // y value for starting position of racket

      // display the racket
      public void displayRacket(){
        fill(0, 0, 0); // color for racket is black
        rect(getStartRacketXPosition(), getStartRacketYPosition(), getRacketWidth(), getRacketHeight());
      }

      // move the racket
      public void moveRacket(){

      }

      // setters
      public void setRacketWidth(int myWidth){
        this.racketWidth = myWidth;
      }

      public void setRacketHeight(int myHeight){
        this.racketHeight = myHeight;
      }

      // getters
      public int getRacketWidth(){
        return this.racketWidth;
      }

      public int getRacketHeight(){
        return this.racketHeight;
      }

      public int getStartRacketXPosition(){
        return startRacketXPosition;
      }

      public int getStartRacketYPosition(){
        return startRacketYPosition;
      }

    } // end class PongRacket

PongRunner课程

    //this is the main class that runs the game
    // it consists of a racket
    // why doesn't the racket get displayed?

    PongRacket racket = new PongRacket(); // creates the racket object

    void setup(){
      size(width, height);
      frame.setResizable(true); // the frame can be resized now
    }

    void draw(){
      background(255); // color for background is white
      racket.displayRacket(); // why isn't this getting displayed?

    }

每当我打电话：

    racket.displayRacket(); // inside the PongRunner class

它不起作用或在屏幕上显示任何内容。我怎样才能让它发挥作用？

Answer 1

我可以发现两个主要问题：

您在致电size()之前创建PongRacket（）（不推荐）
你正在进行整数除法（1/9），（1/15），（4/9），（14/15）。如果你println（）;你会发现每个结果都是0（println(14/15);）。请改用浮点数（println(14.0/15);）

这是一个基本的重构：

PongRacket racket;

void setup() {
  size(width, height);
  frame.setResizable(true); // the frame can be resized now
  racket = new PongRacket(); // creates the racket object

}

void draw() {
  background(255); // color for background is white
  racket.displayRacket(); // why isn't this getting displayed?
}

public class PongRacket {

  // attributes of the pong racket
  private float racketWidth = (1.0/9)*width; // width of the racket
  private float racketHeight = (1.0/15)*height; // height of the racket
  private float startRacketXPosition = (4.0/9)*width; // x value for starting position of racket
  private float startRacketYPosition = (14.0/15)*height; // y value for starting position of racket

    // display the racket
  public void displayRacket() {
    fill(0, 0, 0); // color for racket is black
    rect(getStartRacketXPosition(), getStartRacketYPosition(), getRacketWidth(), getRacketHeight());
  }

  // move the racket
  public void moveRacket() {
  }

  // setters
  public void setRacketWidth(int myWidth) {
    this.racketWidth = myWidth;
  }

  public void setRacketHeight(int myHeight) {
    this.racketHeight = myHeight;
  }

  // getters
  public float getRacketWidth() {
    return this.racketWidth;
  }

  public float getRacketHeight() {
    return this.racketHeight;
  }

  public float getStartRacketXPosition() {
    return startRacketXPosition;
  }

  public float getStartRacketYPosition() {
    return startRacketYPosition;
  }
}

如何在主处理类

1 个答案: