add gesturerecognizer on top right side of navigation bar - ios

Question

I use the following code to add a gesture recognizer on the top right side of uinavigationbar but i get result if i tap anywhere on the navbar. How am i supposed to make a gesture for the top right corner?
- (void)handleGestureForTopRightBarButtonItem:(UIGestureRecognizer *)gestureRecognizer {
CGPoint p = [gestureRecognizer locationInView:self.navigationController.navigationBar];
if (CGRectContainsPoint(CGRectMake(self.navigationController.navigationController.view.width-20,0,100,self.navigationController.navigationController.view.height), p)) {
NSLog(#"got a tap on the right side in the region i care about");
} else {
NSLog(#"got a tap on the right side, but not where i need it");
}
}

Answer 1

As UIGestureRecognizer is reporting to a class object there are a couple of ways to solve this. UIGestureRecognizer was not meant to be stacked multiple times on the same view, if you do so you would very likely drain more Energy than you need apart from the loss of CPU power and lots of comparison code that has to distinguish all the running recognisers. But it would work..
a) write code that compares its coordinates and expected values and if they match in the range you want do your actions.
b) create another object that is living only in the coordinates you want and has it own UIGestureRecognizer. Not ideal, as written above.
c) use the power of UIControl which are also inherited UIView's that are also UIResponders.
- (BOOL)beginTrackingWithTouch:(UITouch *)touch withEvent:(nullable UIEvent *)event;
- (BOOL)continueTrackingWithTouch:(UITouch *)touch withEvent:(nullable UIEvent *)event;
- (void)endTrackingWithTouch:(nullable UITouch *)touch withEvent:(nullable UIEvent *)event; // touch is sometimes nil if cancelTracking calls through to this.
- (void)cancelTrackingWithEvent:(nullable UIEvent *)event;
d) use the power of UIView without a UIGestureRecognizer. Which by the way basically works also on CALayers, they do not have the sendAction methods, they are not UIControls.
-(BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
BOOL inside = [super pointInside:point withEvent:event];
if (inside && event.type == UIEventTypeTouches) {
//[super sendActionsForControlEvents:UIControlEventTouchDown];
}
return inside;
}
e) code some Class that inherits from UIResponder, which basically is what UIControls do and use their API instead so you make use of touch coordinates as well.
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
for (UITouch *touch in touches) {
[self someCoRoutineWithTouch:touch];
}
//[super touchesBegan:touches withEvent:event];
}
-(void)touchesMoved :(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
for (UITouch *touch in touches) {
//do some stuff per touch
}
//[super touchesMoved:touches withEvent:event];
}
-(void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
for (UITouch *touch in touches) {
//do some stuff per touch
}
//[super touchesEnded:touches withEvent:event];
}
-(void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
[self touchesEnded:touches withEvent:event];
}
Just don't forget that UIGestureRecognizer is basically for gestures that are made of touches, even multiple touches but not mainly to catch touches in general, despite in a lot of examples they are used instead of coding a proper UIControl. Also dont forget in a Devices edges the recognition of gestures is limited by the nature of finger size.