[android] #3900 - Using CopyWriteArrayList to avoid concurrency issues with MapChangeListeners

2 files changed, 22 insertions, 18 deletions

diff --git a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapView.java b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapView.java
index d056f6ac9f..f40dff27cf 100644
--- a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapView.java
+++ b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapView.java
@@ -88,7 +88,9 @@ import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.Iterator;
 import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 /**
  * <p>
@@ -124,7 +126,7 @@ public class MapView extends FrameLayout {
     private ImageView mAttributionsView;
     private UserLocationView mUserLocationView;
 
-    private List<OnMapChangedListener> mOnMapChangedListener;
+    private CopyOnWriteArrayList<OnMapChangedListener> mOnMapChangedListener;
     private ZoomButtonsController mZoomButtonsController;
     private ConnectivityReceiver mConnectivityReceiver;
     private float mScreenDensity = 1.0f;
@@ -164,7 +166,7 @@ public class MapView extends FrameLayout {
     }
 
     private void initialize(@NonNull Context context, @Nullable AttributeSet attrs) {
-        mOnMapChangedListener = new ArrayList<>();
+        mOnMapChangedListener = new CopyOnWriteArrayList<>();
         mMapboxMap = new MapboxMap(this);
         mAnnotations = new ArrayList<>();
         mIcons = new ArrayList<>();
@@ -2440,9 +2442,11 @@ public class MapView extends FrameLayout {
     // Forward to any listeners
     protected void onMapChanged(int mapChange) {
         if (mOnMapChangedListener != null) {
-            int count = mOnMapChangedListener.size();
-            for (int i = 0; i < count; i++) {
-                mOnMapChangedListener.get(i).onMapChanged(mapChange);
+            OnMapChangedListener listener;
+            final Iterator<OnMapChangedListener>iterator= mOnMapChangedListener.iterator();
+            while(iterator.hasNext()){
+                listener = iterator.next();
+                listener.onMapChanged(mapChange);
             }
         }
     }
diff --git a/platform/android/MapboxGLAndroidSDKTestApp/src/main/java/com/mapbox/mapboxsdk/testapp/MyLocationTrackingModeActivity.java b/platform/android/MapboxGLAndroidSDKTestApp/src/main/java/com/mapbox/mapboxsdk/testapp/MyLocationTrackingModeActivity.java
index 411ca36316..1f30a4f0ea 100644
--- a/platform/android/MapboxGLAndroidSDKTestApp/src/main/java/com/mapbox/mapboxsdk/testapp/MyLocationTrackingModeActivity.java
+++ b/platform/android/MapboxGLAndroidSDKTestApp/src/main/java/com/mapbox/mapboxsdk/testapp/MyLocationTrackingModeActivity.java
@@ -39,25 +39,13 @@ public class MyLocationTrackingModeActivity extends AppCompatActivity implements
         Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
         setSupportActionBar(toolbar);
 
-        ActionBar actionBar = getSupportActionBar();
+        final ActionBar actionBar = getSupportActionBar();
         if (actionBar != null) {
             actionBar.setDisplayShowTitleEnabled(false);
             actionBar.setDisplayHomeAsUpEnabled(true);
             actionBar.setDisplayShowHomeEnabled(true);
         }
 
-        ArrayAdapter<CharSequence> locationTrackingAdapter = ArrayAdapter.createFromResource(actionBar.getThemedContext(), R.array.user_tracking_mode, android.R.layout.simple_spinner_item);
-        locationTrackingAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
-        mLocationSpinner = (Spinner) findViewById(R.id.spinner_location);
-        mLocationSpinner.setAdapter(locationTrackingAdapter);
-        mLocationSpinner.setOnItemSelectedListener(this);
-
-        ArrayAdapter<CharSequence> bearingTrackingAdapter = ArrayAdapter.createFromResource(actionBar.getThemedContext(), R.array.user_bearing_mode, android.R.layout.simple_spinner_item);
-        bearingTrackingAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
-        mBearingSpinner = (Spinner) findViewById(R.id.spinner_bearing);
-        mBearingSpinner.setAdapter(bearingTrackingAdapter);
-        mBearingSpinner.setOnItemSelectedListener(this);
-
         mMapView = (MapView) findViewById(R.id.mapView);
         mMapView.setAccessToken(ApiAccess.getToken(this));
         mMapView.onCreate(savedInstanceState);
@@ -68,6 +56,18 @@ public class MyLocationTrackingModeActivity extends AppCompatActivity implements
 
                 mapboxMap.setOnMyLocationChangeListener(MyLocationTrackingModeActivity.this);
 
+                ArrayAdapter<CharSequence> locationTrackingAdapter = ArrayAdapter.createFromResource(actionBar.getThemedContext(), R.array.user_tracking_mode, android.R.layout.simple_spinner_item);
+                locationTrackingAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
+                mLocationSpinner = (Spinner) findViewById(R.id.spinner_location);
+                mLocationSpinner.setAdapter(locationTrackingAdapter);
+                mLocationSpinner.setOnItemSelectedListener(MyLocationTrackingModeActivity.this);
+
+                ArrayAdapter<CharSequence> bearingTrackingAdapter = ArrayAdapter.createFromResource(actionBar.getThemedContext(), R.array.user_bearing_mode, android.R.layout.simple_spinner_item);
+                bearingTrackingAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
+                mBearingSpinner = (Spinner) findViewById(R.id.spinner_bearing);
+                mBearingSpinner.setAdapter(bearingTrackingAdapter);
+                mBearingSpinner.setOnItemSelectedListener(MyLocationTrackingModeActivity.this);
+
                 try {
                     mapboxMap.setMyLocationEnabled(true);
                 } catch (SecurityException e) {