title: how to know if UITapGestureRecognizer has been add to subview
body: <p>I adding subviews programmatic. for each subview I'm adding a gesture reconognizer:</p>
  
  <pre><code>UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
      imageView.frame = CGRectMake((position*1024)+200,0,image.size.width,image.size.height);
      UITapGestureRecognizer *singleFingerTap = [[UITapGestureRecognizer alloc]
                                                 initWithTarget:self action:@selector(singleFingerTap:)];
      singleFingerTap.numberOfTapsRequired = 1;
      [imageView addGestureRecognizer:singleFingerTap];
      [singleFingerTap release];
  </code></pre>
  
  <p>but the tap is not responding how can I verify the gesture has been add it to the subview ?</p>