Fix: make sure requestPromise is only invoked once + crash when isLoaded() is called before requestAd() (sbugert#241)

* Fix: make sure we only invoke requestPromise once

* Fix: check if mRewardedVideoAd is not null before calling .isLoaded()

* remove newline

Author: almostintuitive

android/src/main/java/com/sbugert/rnadmob/RNAdMobInterstitialAdModule.java

@@ -81,7 +81,10 @@ public void onAdFailedToLoad(int errorCode) {
                         WritableMap error = Arguments.createMap();
                         event.putString("message", errorMessage);
                         sendEvent(EVENT_AD_FAILED_TO_LOAD, event);
-                        mRequestAdPromise.reject(errorString, errorMessage);
+                        if (mRequestAdPromise != null) {
+                            mRequestAdPromise.reject(errorString, errorMessage);
+                            mRequestAdPromise = null;
+                        }
                     }
                     @Override
                     public void onAdLeftApplication() {
@@ -90,7 +93,10 @@ public void onAdLeftApplication() {
                     @Override
                     public void onAdLoaded() {
                         sendEvent(EVENT_AD_LOADED, null);
-                        mRequestAdPromise.resolve(null);
+                        if (mRequestAdPromise != null) {
+                          mRequestAdPromise.resolve(null);
+                          mRequestAdPromise = null;
+                        }
                     }
                     @Override
                     public void onAdOpened() {

android/src/main/java/com/sbugert/rnadmob/RNAdMobRewardedVideoAdModule.java

@@ -180,7 +180,7 @@ public void showAd(final Promise promise) {
         new Handler(Looper.getMainLooper()).post(new Runnable() {
             @Override
             public void run() {
-                if (mRewardedVideoAd.isLoaded()) {
+                if (mRewardedVideoAd != null && mRewardedVideoAd.isLoaded()) {
                     mRewardedVideoAd.show();
                     promise.resolve(null);
                 } else {
@@ -195,7 +195,11 @@ public void isReady(final Callback callback) {
         new Handler(Looper.getMainLooper()).post(new Runnable() {
             @Override
             public void run() {
-                callback.invoke(mRewardedVideoAd.isLoaded());
+                if (mRewardedVideoAd != null) {
+                    callback.invoke(mRewardedVideoAd.isLoaded());
+                } else {
+                    callback.invoke(false);
+                }
             }
         });
     }