Fix freezing on Android when rotating

Fixes #1941

android/cpp/native_map_view.cpp

@@ -699,6 +699,11 @@ void NativeMapView::updateFps() {
 void NativeMapView::onInvalidate() {
     mbgl::Log::Debug(mbgl::Event::Android, "NativeMapView::onInvalidate()");
 
+    if (map.isPaused()) {
+        mbgl::Log::Debug(mbgl::Event::Android, "Not rendering as map is paused");
+        return;
+    }
+
     const bool dirty = !clean.test_and_set();
     if (dirty) {
         float zoomFactor   = map.getMaxZoom() - map.getMinZoom() + 1;

android/java/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxgl/views/MapView.java

@@ -1009,14 +1009,6 @@ public class MapView extends FrameLayout implements LocationListener {
             mNativeMapView.resizeFramebuffer(width, height);
         }
 
-        // Called when we need to redraw the view
-        // This is called before our view is first visible to prevent an initial
-        // flicker (see Android SDK documentation)
-        /*@Override
-        public void surfaceRedrawNeeded(SurfaceHolder holder) {
-            mNativeMapView.update();
-        }*/ // TODO call update somewhere?
-
         // Not used
         @Override
         public void onSurfaceTextureUpdated (SurfaceTexture surface) {
@@ -1796,7 +1788,6 @@ public class MapView extends FrameLayout implements LocationListener {
         });
     }
 
-
     /**
      * Defines callback for events OnMapChange
      */

android/java/MapboxGLAndroidSDKTestApp/src/main/java/com/mapbox/mapboxgl/testapp/MainActivity.java

@@ -176,12 +176,14 @@ public class MainActivity extends AppCompatActivity {
     @Override
     protected void onStart() {
         super.onStart();
+
         mMapView.onStart();
     }
 
     @Override
     protected void onStop() {
         super.onStop();
+
         mMapView.onStop();
     }
 
@@ -204,6 +206,7 @@ public class MainActivity extends AppCompatActivity {
     @Override
     protected void onDestroy() {
         super.onDestroy();
+
         mMapView.onDestroy();
     }
 

include/mbgl/map/map.hpp

@@ -58,6 +58,7 @@ public:
 
     // Pauses the render thread. The render thread will stop running but will not be terminated and will not lose state until resumed.
     void pause();
+    bool isPaused();
 
     // Resumes a paused render thread
     void resume();

src/mbgl/map/map.cpp

@@ -39,6 +39,10 @@ void Map::pause() {
     }
 }
 
+bool Map::isPaused() {
+    return paused;
+}
+
 void Map::resume() {
     data->condResume.notify_all();
     paused = false;