grid.java

Java 开发的弹跳球小游戏代码. 便于理解OO的概念.

import java.util.Random;


/**
 * 
 * Grid class represents a grid of balloons for bubblet. 
 * This class keeps track of which position has bubble of a particular color.
 */
public class Grid {

	private int[][] grid = null;	// rows in grid are displayed vertically on the GUI
	private int[] length = null; 	// keeps track of the number of bubblets in each row
	private int nColors;			// number of color in use
	private int nRows;				// number of rows in grid
	private int nCols;				// number of cols in grid
	
	public static final int VACANT = -1;	// status of vacant position
	/**
	 * Grid Constructor 
	 */
	public Grid(int nR, int nC, int nColor) 
	{
		nRows = nR;
		nCols = nC;
		this.nColors = nColor;
		length = new int[nR];
		for(int i=0; i<length.length; i++)
		{
			length[i] = nC;
		}//End for each
		
		grid = new int[nR][nC];
		for(int r=0; r<nR; r++)
		{
			for(int c=0; c<nC; c++)
			{
				grid[r][c]= VACANT;
			}//End for c
		}//End for r
		
	}//End Grid Constructor 

	/**
	 * 
	 * @return number of rows in grid
	 */
	public int nrows()
	{
		return nRows;
	}//End nrows 
	
	/**
	 * 
	 * @return number of cols in each row
	 */
	public int ncols()
	{
		return nCols;
	}//End ncols method
	
	/**
	 * set the number of columns in use to val for row row
	 * @param row
	 * @param val
	 */
	public void setLength(int row, int val)
	{
		// number of bubblet in length[row] is val 
		length[row] = val;
		return;
	}//End setLength method
	
	/**
	 * return grid[row]
	 * @param row
	 * @return
	 */
	public int[] get(int row)
	{
		return grid[row];
	}//End get method
	
	/**
	 * fill every position in grid with a random value between 0 and nColors -1
	 */
	public void fill()
	{
		Random
			rand = new Random();
		for(int r=0; r<nRows; r++)
		{
			for(int c=0; c<nCols; c++)
			{
				grid[r][c]= rand.nextInt(this.nColors) ;
			}//End for c
		}//End for r
	}//End fill method
	
	/**
	 * remove the bubble at row row and col col.
	 * 
	 * @param row
	 * @param col
	 */
	public void remove(int r, int c)
	{
		// if length[r] == 0 
			// no remove
		// else
				
			// remove evey element at [r][c],
			// move all elements in row r, starting from c+1, 
			// ending at length[row]-1 toward 0 position
			// set last position [r][length[row]-1] to 0
			// length[r] --
		if(length[r] != 0 )
		{
			System.out.println("length "+ r + " : " + length[r]);
			for(int i=c; i<length[r]-1; i++)
			{
				grid[r][i] = grid[r][i+1];
			}//End for
			grid[r][length[r]-1]= VACANT;
			length[r]--;
		}
			
	}//End remove method
	
    /*
     * set row to to row from 
     */
    public void set(int to, int from)
    {
        grid[to] = grid[from];
        length[to]=length[from];
        return;
    }
    
    /**
     * Testing purpose, set grid[row][col] to v
     * @param row
     * @param col
     * @param v
     */
    public void set(int row, int col, int v)
    {
        grid[row][col] = v;
    }
    
    /**
     * return number of bubbles in row r
     * @param row
     * @return
     */
    public int length(int r)
    {
        return length[r];
    }//End length method
   
    /**
     * get grid[row][col] value
     * @param row
     * @param col
     * @return
     */
    public int get(int row, int col)
    {
        return grid[row][col];
    }
    
    /**
     * print the color of all existing bubbles as text
     *
     */
    public void display()
    {
        System.out.print("   "); 
        for(int k=0; k<nCols; k++)
        {
            System.out.print(k+" "); 
        }//End for k
        System.out.println("");
        for(int i=0; i<nRows; i++)
        {
            System.out.print(i+": ");
            for(int j=0; j<nCols; j++)
            {
                if(grid[i][j]!= VACANT)
                {
                    System.out.print(grid[i][j]+" ");
                }
                else
                {
                    System.out.print("  ");
                }
            }//End for
            System.out.print("\n");
        }//End for
        
        return;
    }//End display method
    
    
    
	/**
	 * @param args
	 */
	public static void main(String[] args) 
	{
       Grid
           g = new Grid(9,9,3); 
	   //g.display();
       g.fill();
       g.display();
       System.out.println("\n\n\n");
       g.remove(3,3);
       g.display();
	}

}//End Grid Class definition