Android中Google Maps集成OpenStreetMap TileOverlay不显示问题排查：是否为Google限制所致？

Problem Description #

I'm integrating Google Maps in my Android project using Java, and I tried adding an OpenStreetMap TileOverlay with the code below, but the tiles won't display. I'm wondering if this is due to restrictions from Google? I've also tried using the tile URL format https://tile.openstreetmap.org/%d/%d/%d.png with no luck.

Here's my code:

@Override
public void onMapReady(GoogleMap map) {
    map.setMapType(GoogleMap.MAP_TYPE_NONE);
    TileProvider tileProvider = new UrlTileProvider(256, 256) {
        @Override
        public synchronized URL getTileUrl(int x, int y, int zoom) {
            String s = String.format("https://tile.openstreetmap.org/%d/%d/%d.jpg", zoom, x, y);
            URL url = null;
            try {
                url = new URL(s);
            } catch (MalformedURLException e) {
                throw new AssertionError(e);
            }
            return url;
        }
    };
    map.addTileOverlay(new TileOverlayOptions().tileProvider(tileProvider));
}

Answer #

First off, Google Maps Android SDK does NOT restrict adding custom TileOverlays—so the issue is almost certainly from other factors. Let's go through the most common fixes:

1. Fix Tile Coordinate Mismatch (Most Likely Culprit)
   Google Maps uses the Web Mercator projection, but the y-coordinate is flipped compared to OpenStreetMap's tile system. This means you're requesting tiles from the wrong location entirely. To fix this, reverse the y-value in your tile URL:

@Override
public synchronized URL getTileUrl(int x, int y, int zoom) {
    // Flip the y-coordinate to match Google Maps' system
    int flippedY = (1 << zoom) - 1 - y;
    String s = String.format("https://tile.openstreetmap.org/%d/%d/%d.png", zoom, x, flippedY);
    URL url = null;
    try {
        url = new URL(s);
    } catch (MalformedURLException e) {
        throw new AssertionError(e);
    }
    return url;
}

2. Check Network Permissions
   Make sure your AndroidManifest.xml includes the required permissions to fetch remote tiles:

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

The INTERNET permission is mandatory for loading external tiles, and ACCESS_NETWORK_STATE helps handle offline scenarios gracefully.

3. Add a Valid User-Agent
   OpenStreetMap's public tile servers require a proper User-Agent header to identify your app—without it, your requests might be blocked to prevent abuse. Create a custom UrlTileProvider to set this header:

private class OSMTileProvider extends UrlTileProvider {
    private static final String USER_AGENT = "YourAppName/1.0 (your.contact.email@example.com)";

    public OSMTileProvider(int width, int height) {
        super(width, height);
    }

    @Override
    public synchronized URL getTileUrl(int x, int y, int zoom) {
        int flippedY = (1 << zoom) - 1 - y;
        String tileUrl = String.format("https://tile.openstreetmap.org/%d/%d/%d.png", zoom, x, flippedY);
        try {
            URL url = new URL(tileUrl);
            // Set User-Agent for the request
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestProperty("User-Agent", USER_AGENT);
            connection.disconnect();
            return url;
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }
}

Then use this custom provider instead of the default UrlTileProvider.

4. Check for OSM Server Restrictions
   While Google doesn't block this, OSM's public servers have rate limits. If you're making too many requests without a valid User-Agent, you might get temporarily blocked. If this happens, consider using alternative OSM tile servers or hosting your own tiles.

5. Verify Layer Initialization Timing
   Double-check that you're adding the TileOverlay only after the GoogleMap instance is fully ready (inside onMapReady), and that no subsequent code is overwriting the map type or removing the overlay.

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