Touch Move

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    if (!dragEnable) {
        return;
    }
    UITouch *touch = [touches anyObject];
    beginPoint = [touch locationInView:self];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    if (!dragEnable) {
        return;
    }
    UITouch *touch = [touches anyObject];
    CGPoint nowPoint = [touch locationInView:self];
    float offsetX = nowPoint.x - beginPoint.x;
    float offsetY = nowPoint.y - beginPoint.y;
    self.center = CGPointMake(self.center.x + offsetX, self.center.y + offsetY);
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
}