Handle java.util.ConcurrentModificationException while unregistering sensor listeners

We're still seeing this frequently when unregistering PlayStation controller sensors. We don't know what else is modifying the sensor list, but if we end up getting this exception we'll retry after a short sleep.

android-project/app/src/main/java/org/libsdl/app/SDLSensorManager.java

@@ -3,6 +3,7 @@ package org.libsdl.app;
 import android.hardware.Sensor;
 import android.hardware.SensorEventListener;
 import android.hardware.SensorManager;
+import android.util.Log;
 
 // This class coordinates synchronized access to sensor manager registration
 //
@@ -13,6 +14,8 @@ class SDLSensorManager
 {
     static private SDLSensorManager mManager = new SDLSensorManager();
 
+    static final int RETRY_COUNT = 3;
+
     public static void registerListener(SensorManager manager, SensorEventListener listener, Sensor sensor, int samplingPeriodUs) {
         mManager.RegisterListener(manager, listener, sensor, samplingPeriodUs);
     }
@@ -22,11 +25,49 @@ class SDLSensorManager
     }
 
     private synchronized void RegisterListener(SensorManager manager, SensorEventListener listener, Sensor sensor, int samplingPeriodUs) {
-        manager.registerListener(listener, sensor, samplingPeriodUs, null);
+        int retries = 0;
+        boolean complete = false;
+        while (!complete) {
+            try {
+                manager.registerListener(listener, sensor, samplingPeriodUs, null);
+                complete = true;
+            } catch (java.util.ConcurrentModificationException e) {
+                ++retries;
+                if (retries <= RETRY_COUNT) {
+                    // Sleep a bit and try again
+                    try {
+                        Thread.sleep(1);
+                    } catch (Exception e2) {
+                    }
+                } else {
+                    Log.v("SDL", "Multiple ConcurrentModificationException caught while registering sensor listener, canceling operation");
+                    complete = true;
+                }
+            }
+        }
     }
 
     private synchronized void UnregisterListener(SensorManager manager, SensorEventListener listener, Sensor sensor) {
-        manager.unregisterListener(listener, sensor);
+        int retries = 0;
+        boolean complete = false;
+        while (!complete) {
+            try {
+                manager.unregisterListener(listener, sensor);
+                complete = true;
+            } catch (java.util.ConcurrentModificationException e) {
+                ++retries;
+                if (retries <= RETRY_COUNT) {
+                    // Sleep a bit and try again
+                    try {
+                        Thread.sleep(1);
+                    } catch (Exception e2) {
+                    }
+                } else {
+                    Log.v("SDL", "Multiple ConcurrentModificationException caught while unregistering sensor listener, canceling operation");
+                    complete = true;
+                }
+            }
+        }
     }
 }