Can't remove imageView from within UIGestureRecognizer? - iphone

Question

I have a photo on the screen which when held, I want to display at full size. Here's the gesture recognizer:
UILongPressGestureRecognizer *hold = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(hold:)];
hold.minimumPressDuration = 0;
[self.photoImageView addGestureRecognizer:hold];
And here's the listener:
-(void)hold:(UILongPressGestureRecognizer *)sender{
UIImageView *img = [[UIImageView alloc] initWithImage:self.photo];
img.userInteractionEnabled = NO;
if(sender.state == UIGestureRecognizerStateBegan){
NSLog(#"state began");
[self.view addSubview:img];
} else if (sender.state == UIGestureRecognizerStateEnded){
NSLog(#"state ended");
[img removeFromSuperview];
}
}
The image gets added to the screen correctly, however [img removeFromSuperview] does not seem to respond. Any reason for this happening? The NSLog for ending state is correctly firing off.

Answer 1

It's because you are creating a new instance of UIImageView instead of removing the one that is displayed.
-(void)hold:(UILongPressGestureRecognizer *)sender{
if(sender.state == UIGestureRecognizerStateBegan){
NSLog(#"state began");
UIImageView *img = [[UIImageView alloc] initWithImage:self.photo];
img.tag = IMAGE_VIEW_TAG;
img.userInteractionEnabled = NO;
[self.view addSubview:img];
} else if (sender.state == UIGestureRecognizerStateEnded){
NSLog(#"state ended");
UIImageView *img = [self.view viewWithTag: IMAGE_VIEW_TAG];
[img removeFromSuperview];
}
}

Answer 2

You don't need to create new imageview in gesture's action. Just add or remove your self.photoImageView like this
-(void)hold:(UILongPressGestureRecognizer *)sender
{
if(sender.state == UIGestureRecognizerStateBegan)
{
NSLog(#"state began");
[self.view addSubview:self.photoImageView];
}
else if (sender.state == UIGestureRecognizerStateEnded)
{
NSLog(#"state ended");
[self.photoImageView removeFromSuperview];
}
}