[Android] Fix RuntimeException in RNImmersiveModule

java.lang.RuntimeException: Tried to access a JS module before the React instance was fully set up. Calls to ReactContext#getJSModule should only happen once initialize() has been called on your native module.
	at com.facebook.react.bridge.ReactContext.getJSModule(ReactContext.java:102)
	at com.rnimmersive.RNImmersiveModule.emitImmersiveStateChangeEvent(RNImmersiveModule.java:74)
	at org.jitsi.meet.sdk.JitsiMeetView.onWindowFocusChanged(JitsiMeetView.java:504)
	at android.view.View.dispatchWindowFocusChanged(View.java:10257)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1193)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1197)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1197)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1197)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1197)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1197)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1197)
	at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:3602)
	at android.os.Handler.dispatchMessage(Handler.java:102)
	at android.os.Looper.loop(Looper.java:154)
	at android.app.ActivityThread.main(ActivityThread.java:6119)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

android/sdk/src/main/java/org/jitsi/meet/sdk/JitsiMeetView.java

@@ -25,6 +25,7 @@ import android.os.Build;
 import android.os.Bundle;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.util.Log;
 import android.widget.FrameLayout;
 
 import com.facebook.react.ReactInstanceManager;
@@ -53,6 +54,12 @@ public class JitsiMeetView extends FrameLayout {
      */
     private static final int BACKGROUND_COLOR = 0xFF111111;
 
+    /**
+     * The {@link Log} tag which identifies the source of the log messages of
+     * {@code JitsiMeetView}.
+     */
+    private final static String TAG = JitsiMeetView.class.getSimpleName();
+
     /**
      * React Native bridge. The instance manager allows embedding applications
      * to create multiple root views off the same JavaScript bundle.
@@ -266,13 +273,15 @@ public class JitsiMeetView extends FrameLayout {
      * @param params {@code WritableMap} optional ancillary data for the event.
      */
     private static void sendEvent(
-            String eventName, @Nullable WritableMap params) {
+            String eventName,
+            @Nullable WritableMap params) {
         if (reactInstanceManager != null) {
             ReactContext reactContext
                 = reactInstanceManager.getCurrentReactContext();
             if (reactContext != null) {
                 reactContext
-                    .getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter.class)
+                    .getJSModule(
+                        DeviceEventManagerModule.RCTDeviceEventEmitter.class)
                     .emit(eventName, params);
             }
         }
@@ -498,10 +507,29 @@ public class JitsiMeetView extends FrameLayout {
         super.onWindowFocusChanged(hasFocus);
 
         // https://github.com/mockingbot/react-native-immersive#restore-immersive-state
+
+        // FIXME The singleton pattern employed by RNImmersiveModule is not
+        // advisable because a react-native mobule is consumable only after its
+        // BaseJavaModule#initialize() has completed and here we have no
+        // knowledge of whether the precondition is really met.
         RNImmersiveModule immersive = RNImmersiveModule.getInstance();
 
         if (hasFocus && immersive != null) {
-            immersive.emitImmersiveStateChangeEvent();
+            try {
+                immersive.emitImmersiveStateChangeEvent();
+            } catch (RuntimeException re) {
+                // FIXME I don't know how to check myself whether
+                // BaseJavaModule#initialize() has been invoked and thus
+                // RNImmersiveModule is consumable. A safe workaround is to
+                // swallow the failure because the whole full-screen/immersive
+                // functionality is brittle anyway, akin to the icing on the
+                // cake, and has been working without onWindowFocusChanged for a
+                // very long time.
+                Log.e(
+                    TAG,
+                    "RNImmersiveModule#emitImmersiveStateChangeEvent() failed!",
+                    re);
+            }
         }
     }