如何显示MapKit指南针？Swift实现显隐控制与常驻显示

Great questions! Let's break down how to handle both scenarios with MapKit in Swift.

By default, the MapKit compass only pops up when you rotate the map (i.e., when the camera heading isn’t pointing north). To keep it visible at all times, we need to override this automatic behavior. Here’s a reliable approach for iOS 11 and later (since MKCompassView became a public class in iOS 11):

Step 1: Confirm compass is enabled #

First, make sure your MKMapView allows compass display (this is enabled by default, but it’s good to explicitly set it):

mapView.showsCompass = true

Step 2: Force the compass to stay visible #

The system automatically hides the compass when the map faces north, so we’ll use Key-Value Observing (KVO) to block that behavior:

In your view controller:

override func viewDidLoad() {
    super.viewDidLoad()
    
    if #available(iOS 11.0, *) {
        // Show the compass right away
        mapView.compassView.isHidden = false
        
        // Add an observer to catch when the system tries to hide it
        mapView.compassView.addObserver(self, forKeyPath: "isHidden", options: .new, context: nil)
    }
}

// Override KVO updates to keep the compass visible
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
    if keyPath == "isHidden", let compassView = object as? MKCompassView {
        // Force the compass to stay visible no matter what
        compassView.isHidden = false
    } else {
        super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
    }
}

// Clean up the observer when the view controller is deallocated
deinit {
    if #available(iOS 11.0, *) {
        mapView.compassView.removeObserver(self, forKeyPath: "isHidden")
    }
}

This will ensure the compass stays on screen regardless of the map’s orientation.

You can manually show or hide the compass at any time with simple property changes. For iOS 11+, this is straightforward using the public MKCompassView class. For older versions, there’s an unofficial fallback (note: it relies on private API details and may break in future iOS updates).

For iOS 11+ #

Use the isHidden property directly to control visibility:

// Show the compass
mapView.compassView.isHidden = false

// Hide the compass
mapView.compassView.isHidden = true

// Toggle visibility (e.g., from a button tap)
@IBAction func toggleCompass(_ sender: UIButton) {
    mapView.compassView.isHidden.toggle()
}

Fallback for iOS <11 (Unofficial) #

If you need to support older iOS versions, you can search for the compass view in the map’s subviews. Keep in mind this isn’t Apple-approved and may stop working with iOS updates:

func toggleCompass() {
    // Find the private compass view class pre-iOS 11
    if let compassView = mapView.subviews.first(where: { $0.className == "MKCompassView" }) {
        compassView.isHidden.toggle()
    }
}

Important note: Always ensure mapView.showsCompass = true before trying to manipulate the compass view—if this is set to false, the compass view won’t exist in the map’s hierarchy at all.

内容的提问来源于stack exchange，提问作者user9225081