CODEWITHSUNDEEP
iosobjective-cuiviewtouchgestures
Alex Stone
Alex Stone

Reputation: 47364

iOS how to capture touches within any view controller?

I'm looking for a way to capture (X,Y) locations of touches that user might be making within screens my app (relative to most backward view of a view controller).

Is there a way for me to subclass some kind of (UIResponder?) or add a category on a UIView to be able to intercept touches, process them, but still allow them to interact with the content (buttons, gesture recognizers, etc)?

I was thinking of implementing "touchesBegan:", but in my experience that frequently messes up existing button or gesture recognizer logic.

Upvotes: 0

Views: 2078

Answers (2)

Legoless
Legoless

Reputation: 11112

This is possible up to some limits. There is a sample project on GitHub by Todd Reed, you can also use that code and modify it for your needs.

Having a quick look at the code, it is keeping a custom UIWindow on top using swizzled methods and rendering touches on that view. It is also using sendEvent: method of the UIApplication class, which redirects the events down the view hierarchy.

This is a much more elegant solution than using UIGestureRecognizer on each view controller. Many analytics solutions are also doing this very effectively.

Upvotes: 1

AtomRiot
AtomRiot

Reputation: 1879

you could have a base View Controller that is a UIGestureRecognizerDelegate that each of your view controllers subclass that has a gesture recognizer on to listen for touches.

-(void)viewDidLoad{
    ...

    UIGestureRecognizer *gestureRecognizer = [[UIGestureRecognizer alloc] initWithTarget:self action:@selector(gestureAction:)];
    [gestureRecognizer setEnabled:YES];
    [gestureRecognizer setCancelsTouchesInView:NO];
    [gestureRecognizer setDelaysTouchesBegan:NO];
    [gestureRecognizer setDelaysTouchesEnded:NO];
    [gestureRecognizer setDelegate:self];
    [self.view addGestureRecognizer:gestureRecognizer];
...
}

and then have your gesture recognizer code

-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{
    NSLog(@"view touch (%f,%f)",[touch locationInView:self.view].x,[touch locationInView:self.view].y);
    return YES;
}

Upvotes: 1

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