如何在Java图形上使用布尔值使积木消失？

Question

I am making a demo version of Atari Arkanoid with Java at school. How would I make bricks that disappear once hit using boolean? It has to collide first, then disappear and not reappear.

    //brickbase
    import java.awt.*;
    public class Brickbase
    {
       private int myX; // x and y coordinates of center
       private int myY;
       private int myXWidth;
       private int myYWidth;
       private Color myColor;

       public Brickbase(int x, int y, int xWidth, int yWidth, Color c)
       {
          myX = x;
          myY = y;
          myXWidth = xWidth;
          myYWidth = yWidth;
          myColor = c;  
       }
        // accessor methods
       public int getX()
       {
          return myX;
       }
       public int getY()
       {
          return myY;
       }
       public int getXWidth()
       {
          return myXWidth;
       }
       public int getYWidth()
       {
          return myYWidth;
       }
       public Color getColor() 
       { 
          return myColor;
       }
       // modifier methods
       public void setX(int x)
       {
          myX= x;
       }

       public void setXWidth(int xWidth)
       {
          myXWidth = xWidth;
       }

       public void setY(int y)
       { 
          myY=y;
       }

       public void setYWidth(int yWidth)
       {
          myYWidth =yWidth;
       }
       public void jump(int rightEdge, int bottomEdge)
       {
          myX= rightEdge;
          myY= bottomEdge;

       }

       public void setColor(java.awt.Color c)
       {
          myColor = c;
       }
        //   instance methods

       public void draw(Graphics myBuffer) 
       {
            myBuffer.setColor(getColor());
             myBuffer.fillRect(getX(), getY(), getXWidth(),                 getYWidth());

       }   

       public boolean inBrickbase(arkBall ark)
       {
          for(int x = getX(); x <= getX() + getXWidth(); x++)           //starts at upper left corner(x,y)
             for(int y = getY(); y <= getY() + getYWidth(); y++)
                if(distance(x, y, ark.getX(), ark.getY()) <= ark.getRadius() ) //checks every point on the bumper
                   return true;            
          return false;
       }  



       private double distance(double x1, double y1, double x2, double y2)
       {
          return Math.sqrt(Math.pow(x1 - x2, 2) + Math.pow(y1 - y2, 2));
       }    
    }

When the ball named ark hits the brick, it bounces off, but the brick is not affected. I know I'm supposed to use boolean, but what would I do? My teacher asks us to do research, but my Java textbook does not incorporate booleans or graphics because it is not part of the AP Curriculum. The sample code for Arkanoid are available, but they are too complicated and sometimes cannot be applied to my code.

Answer 1

So, you need (what's commonly known as a) "flag"

The purpose of this "flag" is to manage a state and provide a means by which you can check for that specific state.

In this case, we want to make the brick invisible when some condition is met.

So, let's start by introducing our "flag" as an instance field to the Brickbase class...

public class Brickbase {

    private boolean visible = true;

Sweet, we know have a means to determine if the brick is visible or not and possibly change that state.

So, obviously, the first thing we might want to do is determine if the brick should be painted or not, based on the state of the "flag", maybe something like...

public void draw(Graphics myBuffer) {
    if (visible) {
        myBuffer.setColor(getColor());
        myBuffer.fillRect(getX(), getY(), getXWidth(), getYWidth());
    }
}

Next, we want to someway to change the state of our "flag", in your case when the brick is hit, maybe something like...

public boolean inBrickbase(arkBall ark) {
    if (visible) {
        for (int x = getX(); x <= getX() + getXWidth(); x++) //starts at upper left corner(x,y)
        {
            for (int y = getY(); y <= getY() + getYWidth(); y++) {
                if (distance(x, y, ark.getX(), ark.getY()) <= ark.getRadius()) //checks every point on the bumper
                {
                    visible = false;
                    return true;
                }
            }
        }
    }
    return false;
}

Now, before someone points it out, I might consider removing the brick from what ever model is managing it when inBrickbase returns true , thus saving all the hassle and reducing the overall computation overhead, but I don't have enough context to derive a solution for that