[android] - use FileSource pause and resume when foregrounding/backgrounding app

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapView.java

@@ -33,6 +33,7 @@ import com.mapbox.mapboxsdk.maps.widgets.CompassView;
 import com.mapbox.mapboxsdk.maps.widgets.MyLocationView;
 import com.mapbox.mapboxsdk.maps.widgets.MyLocationViewSettings;
 import com.mapbox.mapboxsdk.net.ConnectivityReceiver;
+import com.mapbox.mapboxsdk.storage.FileSource;
 import com.mapbox.services.android.telemetry.MapboxTelemetry;
 
 import java.lang.annotation.Retention;
@@ -335,6 +336,7 @@ public class MapView extends FrameLayout {
   @UiThread
   public void onStart() {
     ConnectivityReceiver.instance(getContext()).activate();
+    FileSource.getInstance(getContext()).activate();
     if (mapboxMap != null) {
       mapboxMap.onStart();
     }
@@ -367,6 +369,7 @@ public class MapView extends FrameLayout {
   public void onStop() {
     mapboxMap.onStop();
     ConnectivityReceiver.instance(getContext()).deactivate();
+    FileSource.getInstance(getContext()).deactivate();
   }
 
   /**

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/offline/OfflineRegion.java

@@ -300,10 +300,19 @@ public class OfflineRegion {
 
   /**
    * Pause or resume downloading of regional resources.
+   * <p>
+   * After a download has been completed, you are required to reset the state of the region to STATE_INACTIVE.
+   * </p>
    *
    * @param state the download state
    */
   public void setDownloadState(@DownloadState int state) {
+    if (state == STATE_ACTIVE) {
+      fileSource.activate();
+    } else {
+      fileSource.deactivate();
+    }
+
     this.state = state;
     setOfflineRegionDownloadState(state);
   }

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/storage/FileSource.java

@@ -72,7 +72,7 @@ public class FileSource {
         MapboxConstants.KEY_META_DATA_SET_STORAGE_EXTERNAL,
         MapboxConstants.DEFAULT_SET_STORAGE_EXTERNAL);
     } catch (PackageManager.NameNotFoundException exception) {
-      Timber.e(exception,"Failed to read the package metadata: ");
+      Timber.e(exception, "Failed to read the package metadata: ");
     } catch (Exception exception) {
       Timber.e(exception, "Failed to read the storage key: ");
     }
@@ -119,17 +119,39 @@ public class FileSource {
   }
 
   private long nativePtr;
+  private long activeCounter;
+  private boolean wasPaused;
 
   private FileSource(String cachePath, AssetManager assetManager) {
     initialize(Mapbox.getAccessToken(), cachePath, assetManager);
   }
 
+  public void activate() {
+    activeCounter++;
+    if (activeCounter == 1 && wasPaused) {
+      wasPaused = false;
+      resume();
+    }
+  }
+
+  public void deactivate() {
+    activeCounter--;
+    if (activeCounter == 0) {
+      wasPaused = true;
+      pause();
+    }
+  }
+
   public native void setAccessToken(@NonNull String accessToken);
 
   public native String getAccessToken();
 
   public native void setApiBaseUrl(String baseUrl);
 
+  private native void resume();
+
+  private native void pause();
+
   /**
    * Sets a callback for transforming URLs requested from the internet
    * <p>