基于MapBox SDK的首个iOS应用定位异常求助

Hey there, I see you're running into a common snag when getting started with Mapbox's iOS SDK. The Ghana/Togo border is Mapbox's default fallback location when map tiles fail to load, and the -999 error (which maps to NSURLErrorCancelled) tells us the tile requests are being blocked or cancelled. Let's walk through targeted fixes step by step:

1. Double-Check Your Access Token #

• First, confirm the MGLMapboxAccessToken in your Info.plist is an exact match for the token you generated in the Mapbox dashboard—no extra spaces, typos, or line breaks allowed.
• Head to your Mapbox account and verify the token is a public access token (the default type when you create one) and hasn't been restricted by IP or other filters (new tokens usually don't have restrictions, but it's worth double-checking).

2. Fix App Transport Security (ATS) Settings #

iOS 9+ enforces ATS by default, which can interfere with Mapbox's tile requests even though they use HTTPS. Here's how to configure it properly:

• Open your Info.plist and add this configuration (either via the property list editor or raw XML):

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSExceptionDomains</key>
    <dict>
        <key>mapbox.com</key>
        <dict>
            <key>NSIncludesSubdomains</key>
            <true/>
            <key>NSExceptionRequiresForwardSecrecy</key>
            <false/>
        </dict>
    </dict>
</dict>

• For quick testing, you can temporarily set NSAllowsArbitraryLoads to YES under NSAppTransportSecurity, but avoid this in production apps.

3. Clear Simulator Cache & Reset the App #

The WAL file recovery log in your console suggests corrupted cache data might be causing issues:

• Delete your app from the simulator (long-press the app icon → tap the "X" to delete).
• For a thorough reset, go to Simulator → Reset Content and Settings... to wipe all simulator data, then rebuild and run your app.

4. Verify CocoaPods Installation & SDK Version #

You're using Mapbox-iOS-SDK ~> 3.7, an older 2017-era version that might have compatibility issues with Xcode 9.2:

• Run pod deintegrate in your project directory, delete the Podfile.lock file, then run pod install again to ensure a clean installation.
• Try upgrading to the latest patch version compatible with Xcode 9.2 (like ~> 3.7.1) to rule out version-specific bugs.

5. Confirm MGLMapView IBOutlet Connection #

While your code looks correct, it's worth ruling out a broken connection:

• In Storyboard, right-click your ViewController and check the Connections panel to make sure viewMapBox is properly linked to the MGLMapView in your layout.
• Add a debug print in viewDidLoad: print("Map view:", viewMapBox)—if it prints nil, you'll need to re-establish the IBOutlet connection.

Why This Happens #

The -999 error means Mapbox's tile requests are being cancelled, usually due to network restrictions (ATS), an invalid access token, or corrupted cache. The fallback to the Ghana/Togo border is Mapbox's way of indicating it couldn't load the requested map tiles.

内容的提问来源于stack exchange，提问作者jingo_man