UIImageView tap to hide navigation bar - iphone

Question

I have a view which shows an image from the web. The view only has an UIImageView. I want to know how to hide the navigationBar when the user taps and show it again when the user re-taps the view again. (Just like the native iPhone photo app)
I know i can use this
[self.navigationController setNavigationBarHidden:YES animated:YES];
but i am not sure where to use this,where to put in this code.
Help would be appreciated

Answer 1

Initialize a new UITapGestureRecognizer:
UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(toggleNavigationBar:)];
tapGestureRecognizer.numberOfTapsRequired = 1;
tapGestureRecognizer.numberOfTouchesRequired = 1;
[self.imageView addGestureRecognizer:tapGestureRecognizer];
[tapGestureRecognizer release];
You also must make sure the UIImageView has userInteractionEnabled set to YES because by default it is set to NO on UIImageView's.
self.imageView.userInteractionEnabled = YES;
Finally, write the method that is called when the gesture recognizer recognizes. This is the method selector that is passed in the action: argument in the gesture recognizer's initializer method:
- (void)toggleNavigationBar:(UITapGestureRecognizer *)tapGestureRecognizer
{
[self.navigationController setNavigationBarHidden:![self.navigationController isNavigationBarHidden] animated:YES];
}

Answer 2

Put a UITapGestureRecognizer on your UIImageView and in the delegate just call the method you mentioned. Something like this:
UITapGestureRecognizer* g = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(imageTapped:)];
[img addGestureRecognizer:g];
[g release];
Then your delegate:
-(void) imageTapped:(UITapGestureRecognizer*)tg
{
if(self.navigationController.toolbarHidden)
[self.navigationController setNavigationBarHidden:YES animated:YES];
else
[self.navigationController setNavigationBarHidden:NO animated:YES];
}

Answer 3

If you can't figure out the other answers you can cheat a little bit. You can throw on a button set it to transparent and link a IBAction to it with the code:
UIButton *imageButton = [[UIButton alloc] initWithFrame:CGRectMake( x,y,0,0)];
imageButton.backgroundColor = [UIColor clearColor];
[imageButton addTarget:self action:#selector(navBarHide:)
forControlEvents:UIControlEventTouchUpInside];
-(IBAction)navBarHide {
if (!navBarHidden) {
[self.navigationController.navigationBar removeFromSuperView];
}
else {
[YourUIView addSubview: yourNavigationBar];
}
}