Thread: I can't figure out why this isn't working!

On my current assignment I have to create a brick wall of multi-coloured tiles in java. All using blueJ and as you can see below my code on the "drawRow" method won't work, it just draws a single row and wont actually draw 4 rows with 8 bricks by length when I ask it to. Please help me and ask if you need more info...

import java.util.ArrayList;
/**
 * Write a description of class BrickWall here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class BrickWall
{
    // instance variables - replace the example below with your own
    private Integer bWidth;
    private Integer bHeight;
    private Integer numRows;
    private Integer rowLength;
    private ArrayList<String> colors;
    private ArrayList<Rectangle> bricks;
    private Boolean decrease;
    private Boolean isSymmetric;
    private Boolean isMultiColor;
    private Integer currentColor;
    private Integer startX;
    private Integer startY;
    private Rectangle brick;
 
    /**
     * Constructor for objects of class BrickWall.
     * @param rows The number of rows in the wall
     * @param rowlen The maximum number of bricks in a row
     * @param isMultiColor when false all bricks are the same colour.  When true the colours cycle through the 6 colours.
     * @param decrease If true subtract 2 from rowLen for each row drawn
     * @param isSymmetric if decrease is greater than 0 and isSymmetric is true the wall is a pyramid shape, otherwise it is a rectangle or a right angle triangle.
     */
    public BrickWall(Integer rows, Integer rowLen)
    {
        // initialise instance variables
        setUpColors();
        bWidth = 54;
        bHeight = 16;
        startX = 10;
        startY = 550;
        bricks = new ArrayList<Rectangle>();
        currentColor = 0;
        setNumRows(rows);
        setRowLength(rowLen);
        this.isMultiColor = false;
        this.decrease = false;
        this.isSymmetric = false;
    }
 
    private void setUpColors() {
        colors = new ArrayList<String>();
        colors.add("red");
        colors.add("yellow");
        colors.add("blue"); 
        colors.add("green");
        colors.add("magenta");
        colors.add("black");
    }
 
    /**
     * Toggle whether the wall is multicoloured.
     */
    public void toggleMultiColour() {
        isMultiColor = !isMultiColor;
        currentColor = 0;
    }
 
    /**
     * Toggle whether the decrease in a row length is symmetric.
     */
    public void toggleSymmetric() {
        isSymmetric = !isSymmetric;
    }
 
    /**
     * Toggle whether the length of a new row is one less than the length of the previous row.
     */
    public void toggleDecrease() {
        decrease = ! decrease;
    }
 
    /**
     * @return the number of bricks in the current wall.
     */
    public Integer getNumberOfBricks() {
        return bricks.size();
    }
 
    /**
     * Set the length of a row.  There can be no more than 22 bricks in a row.
     * @param len The number of bricks in a row.  If len is less than or equal
     * to zero OR len is greater than 22, the row length will be assigned the value 22.
     * Otherwise the length of a row will be assigned the value of len.
     */
    public void setRowLength(Integer len) {
        if (len <= 0 || len > 22) {
            rowLength = 22;
        } else {
            rowLength = len;
        }
    }
 
    /**
     * Set the maximum number of rows in the wall.  If the length of a row decreases, 
     * there may not be this many rows in the wall.
     * @param rows The maximum number of rows in the wall.  If rows is less than
     * or equal to zero OR rows is greater than 30, the number of rows will be assigned the value 30.
     * Otherwise the number of rows will be assigned the value of rows.
     */
    public void setNumRows(Integer rows) {
        if (rows <= 0 || rows > 30) {
            numRows = 30;
        } else {
            numRows = rows;
        }
    }
 
    private void drawRow() {
       Integer row = 0;
       while (row <= rowLength) {
           makeBrick();
           startX = startX + 54;
           row++;
        }
    }
 
    private void makeBrick() {
        brick = new Rectangle();
        brick.makeVisible();
        brick.changeSize(bWidth, bHeight);
        brick.setPosition(startX, startY);
        bricks.add(brick);
    }
 
 
    /**
     * Draw the wall.  The first brick will be positioned at the coordinates (10, 550).  
     * The number of bricks in a row is specified by setRowLength().  The maximum number of rows
     * is specified by setNumRows().  If decrease is true, each subsequent row of bricks 
     * contains one brick less than the previous row.  If symmetric is true AND decrease is true then
     * the wall is pyramid shaped.  If symmetric is false AND decrease is true then the wall is shaped
     * like a right angle triangle.
     */
    public void draw()
    {
        eraseWall();
        drawRow();
        boolean decrease = false;
        boolean symmetric = false;
    }
 
 
    public void eraseWall() {
        Canvas canvas = Canvas.getCanvas();
        for (int i=0; !bricks.isEmpty(); i++) {
            canvas.erase(bricks.remove(0));
        }
    }
 
}

Many Thanks for the help in advance,

samjoyboy.

Originally Posted by aussiemcgr

A few questions, because I suspect you've confused yourself:
1. Is the variable rowLength supposed to be the number of bricks in each row, or the number of rows that need to be created? I ask because you are incrementing a variable named row, while incrementing the position of the brick along the X axis only.
2. Each row needs to have a different startY value, or each row will just be drawn over the previous. Where are you adjusting the Y coordinate to move down/up? Remember, X is East and West, and Y is North and South.
3. Where are you telling each row to have 8 bricks, and for it to create 4 rows?

1. rowLength is how many bricks are in each row - this is declared when I create a new brickwall in BlueJ. The make brick creates a brick then the startX moves position of the next brick after the previous however I need to create 8 bricks in each row consisting of 4 rows to get a brick wall.
2. each row needs to start below the previous which is why startY needs to add 16 after each row to go south of the previous row.
3. I tell it to do this from the setRowLength and setNumRows methods.

many thanks.

solved...

     private void drawRow() {
        Integer row1 = 0;
        while (row1 < numRows) {
            for (Integer row = 0; row <= rowLength; row++) {
                makeBrick();
                startX = startX + 54;
            }
            startY = startY + 16;
            startX = 10;
            row1++;
        }
    }

thanks anyhow guys.