Add a UITapGestureRecognizer to a subview - ios

Question

I have been searching for hours ... Needless to say, I'm rather new in programming.
My goal is to display a subview programmatically and to remove it by tapping on it.
Already working: Displaying the subview and removing it by tapping on the view (code below).
Doesn't work - whatever I try: Removing the subview by tapping exclusively on the subview.
Thanks for your help!
My .h-file:
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController {
UIImageView *canvas;
UIImageView *square;
}
#property (nonatomic, strong) UIImageView *canvas;
#property (nonatomic, strong) UIImageView *square;
#property (nonatomic) NSUInteger numberOfTouchesRequired;
- (void)handleSingleTap: (UITapGestureRecognizer *)singleTapGestureRecognizer;
#end
My .m-file:
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
#synthesize canvas;
#synthesize square;
- (void)handleSingleTap: (UITapGestureRecognizer *)singleTapGestureRecognizer {
NSLog(#"tapGesture");
[square removeFromSuperview];
}
- (void)loadView {
canvas = [[UIImageView alloc] initWithFrame: [[UIScreen mainScreen] applicationFrame]];
[canvas setImage:[UIImage imageNamed:#"canvas.png"]];
self.view = canvas;
square = [[UIImageView alloc] initWithFrame:CGRectMake(170, 320, 40, 40)];
[square setImage:[UIImage imageNamed:#"square.png"]];
[self.view setUserInteractionEnabled:YES];
[canvas addSubview:square];
NSLog(#"square");
}
- (void)viewDidLoad {
[super viewDidLoad];
UITapGestureRecognizer *singleTapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleSingleTap:)];
NSLog(#"initialize");
singleTapGestureRecognizer.numberOfTapsRequired = 1;
NSLog(#"number of taps");
[self.view addGestureRecognizer:singleTapGestureRecognizer];
NSLog(#"square gestureRecognizer");
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end

Answer 1

If you want to remove a subview exclusively, when you tap on that view, then you will need to add tap gesture on that view
[square addGestureRecognizer:singleTapGestureRecognizer];
rather than
[self.view addGestureRecognizer:singleTapGestureRecognizer];
Edit
Also you will need to setUserInteractionEnabled to YES of UIImage because UIImage's setUserInteractionEnabled is default to NO.
[square setUserInteractionEnabled:YES];

Answer 2

Instead of
[self.view addGestureRecognizer:singleTapGestureRecognizer];
you should say
[square addGestureRecognizer:singleTapGestureRecognizer];