Question

I’m busy with an app you need to touch a button, but when u touch outside the button (on the background of the app screen) i want to display an alert.

Does anyone know how to detect an tap on the background

Button:

   MyButton = [UIButton buttonWithType:UIButtonTypeCustom];
    MyButton.frame = CGRectMake(0, 0, 100, 100);
    [MyButton setImage:[UIImage imageNamed:@"tap.png"] forState:nil];
    [self.view addSubview:MyButton];

    [MyButton addTarget:self action:@selector(buttonPressed) forControlEvents:UIControlEventTouchUpInside];

Answer 1

You could add a gesture recogniser to the view.

E.g.

// in viewDidLoad:
UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(backgroundTapped:)];
tapRecognizer.numberOfTapsRequired = 1;
[self.view addGestureRecognizer:tapRecognizer];

- (void)backgroundTapped:(UITapGestureRecognizer*)recognizer {
    // display alert
}

What you could also try is having a full size UIView behind the button that has a gesture recogniser on it:

// in viewDidLoad:
UIView *backgroundView = [[UIView alloc] initWithFrame:self.view.bounds];
backgroundView.backgroundColor = [UIColor clearColor];
backgroundView.opaque = NO;
[self.view addSubview:backgroundView];

UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(backgroundTapped:)];
tapRecognizer.numberOfTapsRequired = 1;
[backgroundView addGestureRecognizer:tapRecognizer];

- (void)backgroundTapped:(UITapGestureRecognizer*)recognizer {
    // display alert
}

This might work better than adding the gesture recogniser to self.view.