Canvas OnDraw method | 易学教程

问题

I am currently creating a maze using a pair of boolean array (horizontal and vertical) in order to draw lines for the maze.

The maze only every displays 5 bools from the array at one time. Then, I have an user who is always centered and as he moves through the maze the next set of bools are drawn. This is working as it should.

The issue that I am having is: when the user moves to a certain part of the maze the for loop drawing the lines becomes higher than the bool array and therefore crashes the app. Please find below some code snippets.

The onDraw:

protected void onDraw(Canvas canvas) {
    canvas.drawRect(0, 0, width, height, background);
    int currentX = maze.getCurrentX(),currentY = maze.getCurrentY();
    int drawSizeX = 6 + currentX;
    int drawSizeY = 6 + currentY;
    currentX = currentX - 2;
    currentY = currentY - 2;

    for(int i = 0; i < drawSizeX - 1; i++)  {
        for(int j = 0; j < drawSizeY - 1; j++)  {
            float x = j * totalCellWidth;
            float y = i * totalCellHeight;
            if(vLines[i + currentY][j + currentX])  {
                canvas.drawLine(x + cellWidth,   //start X
                                y,               //start Y
                                x + cellWidth,   //stop X
                                y + cellHeight,  //stop Y
                                line);
            }
            if(hLines[i + currentY][j + currentX]) {
                canvas.drawLine(x,               //startX 
                                y + cellHeight,  //startY 
                                x + cellWidth,   //stopX 
                                y + cellHeight,  //stopY 
                                line);
            }
        }
        //draw the user ball
        canvas.drawCircle((2 * totalCellWidth)+(cellWidth/2),   //x of center
                          (2 * totalCellHeight)+(cellWidth/2),  //y of center
                          (cellWidth*0.45f),                    //radius
                          ball);
    }

EDIT 1 - The Move -

public boolean move(int direction) {
    boolean moved = false;
    if(direction == UP) {
        if(currentY != 0 && !horizontalLines[currentY-1][currentX]) {
            currentY--;
            moved = true;
        }
    }
    if(direction == DOWN) {
        if(currentY != sizeY-1 && !horizontalLines[currentY][currentX]) {
            currentY++;
            moved = true;
        }
    }
    if(direction == RIGHT) {
        if(currentX != sizeX-1 && !verticalLines[currentY][currentX]) {
            currentX++;
            moved = true;
        }
    }
    if(direction == LEFT) {
        if(currentX != 0 && !verticalLines[currentY][currentX-1]) {
            currentX--;
            moved = true;
        }
    }
    if(moved) {
        if(currentX == finalX && currentY == finalY) {
            gameComplete = true;
        }
    }
    return moved;
}

If there is anything else that I need to clarify please let me know.

Thanks in advance.