-(void) testTap:(id)sender {
    NSLog(@"Test tap...");
}
 
-(void) testSlide {
    UITapGestureRecognizer* testTap = [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(testTap:)] autorelease];
    testTap.numberOfTapsrequired = 2;
 
    UIImageView* imageView = [[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"tip_slide"]] autorelease];
    [imageView setFrame:CGRectMake(40,40,200,200)];
    imageView.userInteractionEnabled = YES;
    imageView.multipleTouchEnabled = YES;
    [imageView addGestureRecognizer:testTap];
 
    [self.view addSubview:imageView];
 
 
    // When I add the following code,the UITapGestureRecognizer will not work. WHY???
    imageView.alpha = 0;
    CGAffineTransform t = imageView.transform;
    if (CGAffineTransformIsIdentity(t)) {
        UIViewAnimationOptions options = UIViewAnimationCurveEaseInOut;
        [UIView animateWithDuration:1.0 delay:0 options:options animations:^{
            imageView.alpha = 1.0;
        } completion:^(BOOL finished) {
            if (finished) {
                [UIView animateWithDuration:1.0 delay:2.0 options:options animations:^{
                imageView.alpha = 0.4;
                } completion:^(BOOL finished) {
                    if (finished) {
                        [imageView removeFromSuperview];
                    }
                }];
            }
        }];
    }
}