Swift 4+Xcode9.2下MapKit报错‘Could not inset legal attribution from corner 4’求解决

Hey there, I’ve dealt with this exact frustrating MapKit error back when working with Xcode 9.x and Swift 4—let me share the solutions that got rid of it for me:

Common Causes & Fixes #

1. Check Your MapView Layout Constraints #

This error almost always boils down to the map view not having enough space to display its legal attribution text (the copyright info in the bottom-right corner, which is "corner 4" in MapKit's terminology).

• Storyboard/Nib Users: Make sure your MKMapView is properly constrained to its parent view, with no overlapping views blocking the bottom-right corner. Double-check that there’s no conflicting constraints pushing the map view out of bounds, or a subview (like a button, tab bar, or tool) covering that area. Leave at least 20pt of clear space in the bottom-right for the attribution.
• Code-Based Layout: If you’re creating the map view programmatically, ensure you’re setting up constraints correctly to fit the parent view. Here’s a safe example:

  let mapView = MKMapView()
  mapView.translatesAutoresizingMaskIntoConstraints = false
  view.addSubview(mapView)
  
  NSLayoutConstraint.activate([
      mapView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
      mapView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
      mapView.topAnchor.constraint(equalTo: view.topAnchor),
      mapView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
  ])
  

  Avoid hardcoding frames unless absolutely necessary—autolayout will ensure the map view adjusts correctly to leave space for attribution.

2. Remove Custom Attribution Modifications #

If you’re trying to hide or reposition the MapKit attribution (e.g., using showsAttribution = false or custom subview manipulations), stop right there. Older versions of MapKit (like the one in Xcode 9.2) had bugs when you tried to override the default attribution behavior.

• Comment out any lines that modify the attribution visibility or position. Apple requires the legal attribution to be displayed, so even if you could hide it, it’s against their guidelines anyway.

3. Try Updating Xcode (If Possible) #

Xcode 9.2 is pretty outdated, and this specific attribution bug was fixed in later versions of Xcode (and corresponding MapKit frameworks). If your project can support it, upgrading to Xcode 9.4.1 (the last release in the Xcode 9 line) or newer should resolve the issue without extra code changes.

4. Verify MapView Initialization #

If you’re initializing the map view with a frame that’s too small or doesn’t fit its parent, this error can pop up. Make sure:

• The map view’s frame matches its parent view’s bounds when using manual layout.
• You’ve set autoresizingMask correctly if you’re not using autolayout:

  mapView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
  

Quick Troubleshooting Steps #

1. Temporarily remove all other subviews from the map view’s parent to rule out overlapping views.
2. Run the app on a physical device (sometimes simulator-specific layout quirks cause this).
3. Clean your project (Cmd+Shift+K) and rebuild to clear any cached layout issues.

内容的提问来源于stack exchange，提问作者user6421566