Show UIButton when Image is touched? - iphone

Question

is there any way to hide an UIButton until the UIImageView is pressed??
When the picture is pressed I need to show the back Button, like it works at the Photo App on the iPhone???
Here is the code of my UIButton:
- (void)viewDidLoad {
[super viewDidLoad];
[self ladeImage];
UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
btn.frame = CGRectMake(10, 10, 40, 40);
[btn addTarget:self action:#selector(goToViewA) forControlEvents:UIControlEventTouchUpInside];
[btn setTitle:#"<<" forState:UIControlStateNormal];
[self.view addSubview:btn];
}

Answer 1

First step : btn.hidden = YES
Then you have to subclass the UIImageView to react to its touchesEnded: event and change the hidden property of your button there. For that, the proper way is to create a protocol (with a viewTouched method). Implement that protocol in the viewController containing your button and you ImageView. Add a delegate propery to the subclassed ImageView (i.e. id<MyCustomProtocol> _delagate;) and assign the view controller to this propery.

Answer 2

btn.hidden = YES;
UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"image name"]];
imageView.userInteractionEnabled = YES; // here to enable touch event
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleTapGestureRecongizer:)]; // handleTapGestureRecongizer is method will call when tap even fire
[imageView addGestureRecognizer:tap]; // Add Tap gesture recognizer to image view
[tap release], tap = nil;
[self.view addSubview:imageView];
[imageView release], imageView = nil;
Method handlerTapGestureRecognizer:
- (void)handleTapGestureRecongizer:(UITapGestureRecognizer *)gestureRecognizer{
if (gestureRecognizer.state == UIGestureRecognizerStateEnded) {
btn.hidden = NO;
}
}
have fun!