[android] Expose pre-fetching zoom delta.

5 files changed, 68 insertions, 2 deletions

diff --git a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapboxMap.java b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapboxMap.java
index acd5093dad..b6b9004fc2 100644
--- a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapboxMap.java
+++ b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapboxMap.java
@@ -6,6 +6,7 @@ import android.graphics.PointF;
 import android.graphics.RectF;
 import android.os.Bundle;
 import android.support.annotation.FloatRange;
+import android.support.annotation.IntRange;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.annotation.Size;
@@ -274,6 +275,28 @@ public final class MapboxMap {
     return nativeMapView.getPrefetchTiles();
   }
 
+  /**
+   * Set the tile pre-fetching zoom delta. Pre-fetching makes sure that a low-resolution
+   * tile at the (current_zoom_level - delta) is rendered as soon as possible at the
+   * expense of a little bandwidth.
+   *
+   * @param delta zoom delta
+   */
+  public void setPrefetchZoomDelta(@IntRange(from = 0) int delta) {
+    nativeMapView.setPrefetchZoomDelta(delta);
+  }
+
+  /**
+   * Check current pre-fetching zoom delta.
+   *
+   * @return current zoom delta.
+   * @see MapboxMap#setPrefetchZoomDelta(int)
+   */
+  @IntRange(from = 0)
+  public int getPrefetchZoomDelta() {
+    return nativeMapView.getPrefetchZoomDelta();
+  }
+
   //
   // MinZoom
   //
diff --git a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/NativeMap.java b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/NativeMap.java
index 7f3017c7ae..c805dcddb0 100644
--- a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/NativeMap.java
+++ b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/NativeMap.java
@@ -6,6 +6,7 @@ import android.graphics.RectF;
 import android.support.annotation.IntRange;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+
 import com.mapbox.geojson.Feature;
 import com.mapbox.geojson.Geometry;
 import com.mapbox.mapboxsdk.annotations.Marker;
@@ -214,6 +215,11 @@ interface NativeMap {
 
   boolean getPrefetchTiles();
 
+  void setPrefetchZoomDelta(@IntRange(from = 0) int delta);
+
+  @IntRange(from = 0)
+  int getPrefetchZoomDelta();
+
   void setGestureInProgress(boolean inProgress);
 
   float getPixelRatio();
diff --git a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/NativeMapView.java b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/NativeMapView.java
index c844133f41..75ca5edfca 100755
--- a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/NativeMapView.java
+++ b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/NativeMapView.java
@@ -724,6 +724,23 @@ final class NativeMapView implements NativeMap {
     return nativeGetPrefetchTiles();
   }
 
+  @Override
+  public void setPrefetchZoomDelta(@IntRange(from = 0) int delta) {
+    if (checkState("nativeSetPrefetchZoomDelta")) {
+      return;
+    }
+    nativeSetPrefetchZoomDelta(delta);
+  }
+
+  @Override
+  @IntRange(from = 0)
+  public int getPrefetchZoomDelta() {
+    if (checkState("nativeGetPrefetchZoomDelta")) {
+      return 0;
+    }
+    return nativeGetPrefetchZoomDelta();
+  }
+
   // Runtime style Api
 
   @Override
@@ -1383,6 +1400,12 @@ final class NativeMapView implements NativeMap {
   @Keep
   private native boolean nativeGetPrefetchTiles();
 
+  @Keep
+  private native void nativeSetPrefetchZoomDelta(int delta);
+
+  @Keep
+  private native int nativeGetPrefetchZoomDelta();
+
   @Override
   public long getNativePtr() {
     return nativePtr;
diff --git a/platform/android/src/native_map_view.cpp b/platform/android/src/native_map_view.cpp
index 7b87693cf5..9eb7d48708 100755
--- a/platform/android/src/native_map_view.cpp
+++ b/platform/android/src/native_map_view.cpp
@@ -50,7 +50,7 @@
 #include "java/util.hpp"
 #include "geometry/lat_lng_bounds.hpp"
 #include "map/camera_position.hpp"
-#include  "map/image.hpp"
+#include "map/image.hpp"
 #include "style/light.hpp"
 #include "bitmap_factory.hpp"
 
@@ -1050,6 +1050,14 @@ jni::jboolean NativeMapView::getPrefetchTiles(JNIEnv&) {
     return jni::jboolean(map->getPrefetchZoomDelta() > 0);
 }
 
+void NativeMapView::setPrefetchZoomDelta(JNIEnv&, jni::jint delta) {
+    map->setPrefetchZoomDelta(uint8_t(abs(delta)));
+}
+
+jni::jint NativeMapView::getPrefetchZoomDelta(JNIEnv&) {
+    return jni::jint(map->getPrefetchZoomDelta());
+}
+
 mbgl::Map& NativeMapView::getMap() {
     return *map;
 }
@@ -1145,7 +1153,9 @@ void NativeMapView::registerNative(jni::JNIEnv& env) {
             METHOD(&NativeMapView::getImage, "nativeGetImage"),
             METHOD(&NativeMapView::setLatLngBounds, "nativeSetLatLngBounds"),
             METHOD(&NativeMapView::setPrefetchTiles, "nativeSetPrefetchTiles"),
-            METHOD(&NativeMapView::getPrefetchTiles, "nativeGetPrefetchTiles")
+            METHOD(&NativeMapView::getPrefetchTiles, "nativeGetPrefetchTiles"),
+            METHOD(&NativeMapView::setPrefetchZoomDelta, "nativeSetPrefetchZoomDelta"),
+            METHOD(&NativeMapView::getPrefetchZoomDelta, "nativeGetPrefetchZoomDelta")
     );
 }
 
diff --git a/platform/android/src/native_map_view.hpp b/platform/android/src/native_map_view.hpp
index ba2178022e..5a340d1287 100755
--- a/platform/android/src/native_map_view.hpp
+++ b/platform/android/src/native_map_view.hpp
@@ -235,6 +235,10 @@ public:
 
     jni::jboolean getPrefetchTiles(JNIEnv&);
 
+    void setPrefetchZoomDelta(JNIEnv&, jni::jint);
+
+    jni::jint getPrefetchZoomDelta(JNIEnv&);
+
     mbgl::Map& getMap();
 
 private: