mapsforge · devemux86 · Mar 11, 2025 · Mar 11, 2025
diff --git a/docs/Changelog.md b/docs/Changelog.md
@@ -4,6 +4,7 @@
 
 - Hillshading from HGT digital elevation model data [#1189](https://github.com/mapsforge/vtm/pull/1189)
   - `vtm-hillshading` module
+- Online tiles support multiple servers [#1196](https://github.com/mapsforge/vtm/pull/1196)
 - Motorider map theme improvements [#1183](https://github.com/mapsforge/vtm/issues/1183)
 - Biker map theme improvements [#1192](https://github.com/mapsforge/vtm/issues/1192)
 - Rename `MapDatabase` to `MapFile` [#1184](https://github.com/mapsforge/vtm/pull/1184)

diff --git a/vtm-playground/src/org/oscim/test/BitmapTileTest.java b/vtm-playground/src/org/oscim/test/BitmapTileTest.java
@@ -20,7 +20,9 @@
 import org.oscim.gdx.GdxMapApp;
 import org.oscim.layers.tile.bitmap.BitmapTileLayer;
 import org.oscim.renderer.MapRenderer;
+import org.oscim.tiling.source.OkHttpEngine;
 import org.oscim.tiling.source.UrlTileSource;
+import org.oscim.tiling.source.bitmap.BitmapTileSource;
 import org.oscim.tiling.source.bitmap.DefaultSources;
 
 import java.util.Collections;
@@ -36,7 +38,9 @@ protected boolean onKeyDown(int keycode) {
             mMap.layers().remove(mShaded);
             mShaded = null;
             mMap.layers().remove(mLayer);
-            UrlTileSource tileSource = DefaultSources.OPENSTREETMAP.build();
+            UrlTileSource tileSource = DefaultSources.OPENSTREETMAP
+                    .httpFactory(new OkHttpEngine.OkHttpFactory())
+                    .build();
             tileSource.setHttpRequestHeaders(Collections.singletonMap("User-Agent", "vtm-playground"));
             mLayer = new BitmapTileLayer(mMap, tileSource);
             mMap.layers().add(mLayer);
@@ -46,7 +50,10 @@ protected boolean onKeyDown(int keycode) {
             mMap.layers().remove(mShaded);
             mShaded = null;
             mMap.layers().remove(mLayer);
-            mLayer = new BitmapTileLayer(mMap, DefaultSources.STAMEN_TONER.build());
+            final BitmapTileSource tileSource = DefaultSources.STAMEN_TONER
+                    .httpFactory(new OkHttpEngine.OkHttpFactory())
+                    .build();
+            mLayer = new BitmapTileLayer(mMap, tileSource);
             mMap.layers().add(mLayer);
             mMap.clearMap();
             return true;
@@ -55,7 +62,10 @@ protected boolean onKeyDown(int keycode) {
                 mMap.layers().remove(mShaded);
                 mShaded = null;
             } else {
-                mShaded = new BitmapTileLayer(mMap, DefaultSources.HIKEBIKE_HILLSHADE.build());
+                final BitmapTileSource tileSource = DefaultSources.HIKEBIKE_HILLSHADE
+                        .httpFactory(new OkHttpEngine.OkHttpFactory())
+                        .build();
+                mShaded = new BitmapTileLayer(mMap, tileSource);
                 mMap.layers().add(mShaded);
             }
             mMap.clearMap();
@@ -69,7 +79,9 @@ protected boolean onKeyDown(int keycode) {
     public void createLayers() {
         MapRenderer.setBackgroundColor(0xff888888);
 
-        UrlTileSource tileSource = DefaultSources.OPENSTREETMAP.build();
+        UrlTileSource tileSource = DefaultSources.OPENSTREETMAP
+                .httpFactory(new OkHttpEngine.OkHttpFactory())
+                .build();
         tileSource.setHttpRequestHeaders(Collections.singletonMap("User-Agent", "vtm-playground"));
         mLayer = new BitmapTileLayer(mMap, tileSource);
         mMap.layers().add(mLayer);

diff --git a/vtm/src/org/oscim/tiling/source/UrlTileSource.java b/vtm/src/org/oscim/tiling/source/UrlTileSource.java
@@ -27,12 +27,13 @@
 import java.net.URL;
 import java.util.Collections;
 import java.util.Map;
+import java.util.Random;
 
 public abstract class UrlTileSource extends TileSource {
 
     public abstract static class Builder<T extends Builder<T>> extends TileSource.Builder<T> {
         protected String tilePath;
-        protected String url;
+        protected String[] urls;
         private HttpEngine.Factory engineFactory;
         private String keyName = "key";
         private String apiKey;
@@ -41,7 +42,7 @@ protected Builder() {
         }
 
         protected Builder(String url, String tilePath) {
-            this.url = url;
+            this.urls = new String[]{url};
             this.tilePath = tilePath;
         }
 
@@ -66,8 +67,8 @@ public T tilePath(String tilePath) {
             return self();
         }
 
-        public T url(String url) {
-            this.url = url;
+        public T url(String... urls) {
+            this.urls = urls;
             return self();
         }
 
@@ -79,7 +80,8 @@ public T httpFactory(HttpEngine.Factory factory) {
     }
 
     public static final TileUrlFormatter URL_FORMATTER = new DefaultTileUrlFormatter();
-    private final URL mUrl;
+    private final Random mRandom = new Random();
+    private final URL[] mUrls;
     private final String[] mTilePath;
 
     private HttpEngine.Factory mHttpFactory;
@@ -96,7 +98,7 @@ protected UrlTileSource(Builder<?> builder) {
         super(builder);
         mKeyName = builder.keyName;
         mApiKey = builder.apiKey;
-        mUrl = makeUrl(builder.url);
+        mUrls = makeUrl(builder.urls);
         mTilePath = builder.tilePath.split("\\{|\\}");
         mHttpFactory = builder.engineFactory;
     }
@@ -107,7 +109,7 @@ protected UrlTileSource(String urlString, String tilePath) {
 
     protected UrlTileSource(String urlString, String tilePath, int zoomMin, int zoomMax) {
         super(zoomMin, zoomMax);
-        mUrl = makeUrl(urlString);
+        mUrls = makeUrl(urlString);
         mTilePath = makeTilePath(tilePath);
     }
 
@@ -118,14 +120,16 @@ private String[] makeTilePath(String tilePath) {
         return tilePath.split("\\{|\\}");
     }
 
-    private URL makeUrl(String urlString) {
-        URL url;
-        try {
-            url = new URL(urlString);
-        } catch (MalformedURLException e) {
-            throw new IllegalArgumentException(e);
+    private URL[] makeUrl(String... urlStrings) {
+        URL[] urls = new URL[urlStrings.length];
+        for (int i = 0; i < urlStrings.length; i++) {
+            try {
+                urls[i] = new URL(urlStrings[i]);
+            } catch (MalformedURLException e) {
+                throw new IllegalArgumentException(e);
+            }
         }
-        return url;
+        return urls;
     }
 
     @Override
@@ -143,12 +147,12 @@ public void setApiKey(String apiKey) {
     }
 
     public URL getUrl() {
-        return mUrl;
+        return mUrls[mRandom.nextInt(mUrls.length)];
     }
 
     public String getTileUrl(Tile tile) {
         StringBuilder sb = new StringBuilder();
-        sb.append(mUrl).append(mTileUrlFormatter.formatTilePath(this, tile));
+        sb.append(getUrl()).append(mTileUrlFormatter.formatTilePath(this, tile));
         if (mApiKey != null) {
             sb.append("?").append(mKeyName).append("=").append(mApiKey);
         }

diff --git a/vtm/src/org/oscim/tiling/source/bitmap/DefaultSources.java b/vtm/src/org/oscim/tiling/source/bitmap/DefaultSources.java
@@ -37,7 +37,7 @@ public class DefaultSources {
     // Requires a valid HTTP User-Agent identifying application
     // https://operations.osmfoundation.org/policies/tiles/
     public static Builder<?> OPENSTREETMAP = BitmapTileSource.builder()
-            .url("https://tile.openstreetmap.org")
+            .url("https://a.tile.openstreetmap.org", "https://b.tile.openstreetmap.org", "https://c.tile.openstreetmap.org")
             .zoomMax(18);
 
     public static Builder<?> STAMEN_TONER = BitmapTileSource.builder()