The code below is from the book Beginning iPhone 3 Development, chapter 15, using the accelerometer to control a ball. I want to use a label instead of the ball, and only move in the x direction. However, I donno how to revise the code to achieve this goal. Can anyone please help me? THX so much!!!!

• (id)initWithCoder:(NSCoder *)coder {

  if (self = [super initWithCoder:coder]) { self.image = [UIImage imageNamed:@"ball.png"]; self.currentPoint = CGPointMake((self.bounds.size.width / 2.0f) + (image.size.width / 2.0f), (self.bounds.size.height / 2.0f) + (image.size.height / 2.0f));

  ballXVelocity = 0.0f;
  ballYVelocity = 0.0f;
  

  } return self; }

• (id)initWithFrame:(CGRect)frame { if (self = [super initWithFrame:frame]) { // Initialization code } return self; }

• (void)drawRect:(CGRect)rect { // Drawing code [image drawAtPoint:currentPoint]; }

• (void)dealloc { [image release]; [acceleration release];

  [super dealloc]; }

//#pragma mark - - (CGPoint)currentPoint {

return currentPoint;

} - (void)setCurrentPoint:(CGPoint)newPoint { previousPoint = currentPoint; currentPoint = newPoint;

if (currentPoint.x < 0) {
    currentPoint.x = 0;
    //ballXVelocity = 0;
    ballXVelocity = - (ballXVelocity / 2.0);
}
if (currentPoint.y < 0){
    currentPoint.y = 0;
    //ballYVelocity = 0;
    ballYVelocity = - (ballYVelocity / 2.0);
} 
if (currentPoint.x > self.bounds.size.width - image.size.width) {
    currentPoint.x = self.bounds.size.width  - image.size.width; 
     //ballXVelocity = 0;
    ballXVelocity = - (ballXVelocity / 2.0);
}
if (currentPoint.y > self.bounds.size.height - image.size.height) {
    currentPoint.y = self.bounds.size.height - image.size.height;
    //ballYVelocity = 0;
    ballYVelocity = - (ballYVelocity / 2.0);
}

CGRect currentImageRect = CGRectMake(currentPoint.x, currentPoint.y, 
                                     currentPoint.x + image.size.width, 
                                     currentPoint.y + image.size.height);
CGRect previousImageRect = CGRectMake(previousPoint.x, previousPoint.y,
                                      previousPoint.x + image.size.width,  
                                      currentPoint.y + image.size.width);
[self setNeedsDisplayInRect:CGRectUnion(currentImageRect,
                                        previousImageRect)];

}

• (void)draw { static NSDate *lastDrawTime;

  if (lastDrawTime != nil) { NSTimeInterval secondsSinceLastDraw = -([lastDrawTime timeIntervalSinceNow]);

  ballYVelocity = ballYVelocity + -(acceleration.y *
                                    secondsSinceLastDraw);
  ballXVelocity = ballXVelocity + acceleration.x *
  secondsSinceLastDraw;
  
  
  CGFloat xAcceleration = secondsSinceLastDraw * ballXVelocity * 500;
  CGFloat yAcceleration = secondsSinceLastDraw * ballYVelocity * 500;
  
  
  self.currentPoint = CGPointMake(self.currentPoint.x + xAcceleration,
                                  self.currentPoint.y +yAcceleration);
  

  } // Update last time with current time [lastDrawTime release]; lastDrawTime = [[NSDate alloc] init];

}