Preventing annotation deselection in MKMapView

Question

I have a situation in my app where I want to disable annotation deselection (other than when selecting another), so when I tap anywhere that is not an annotation view, it should leave the currently selected annotation as is. If I tap on another annotation view, it should select that one and deselect the other.

I was hoping to find something along the lines of a willDeselectAnnotationView in the MKMapViewDelegate or an isDeselected in MKAnnotationView, but there's unfortunately no such thing. I also tried overriding deselectAnnotation in a custom subclass of MKMapView, but it seems the tap triggered deselect doesn't invoke that function.

Is it possible to disable annotation deselection while preserving the ability to select? Thanks!

Answer 1

I've found a way to do it! Make a boolean named something like "allowSelectionChanges", which I just have as global for now. Then use a subclass of MKMapView with this overriden function inside:

override func gestureRecognizerShouldBegin(gestureRecognizer: UIGestureRecognizer) -> Bool {
        return allowSelectionChanges
    } 

Switch this variable to false whenever you want to prevent annotation selection and deselection. It won't affect the user's ability to move around the map!

---

Here's an example of how this can be used to stop a callout from getting deselected when you tap on it to interact with it. Put this in your MKAnnotationView subclass:

override func pointInside(point: CGPoint, withEvent event: UIEvent?) -> Bool {
        let rect = self.bounds
        var isInside = CGRectContainsPoint(rect, point)
        if !isInside {
            for view in self.subviews {
                isInside = CGRectContainsPoint(view.frame, point)
                if isInside {
                    allowSelectionChanges = false
                    return true
                }
            }
            allowSelectionChanges = true
        }

        return false
    }