Fixing white square icon and annotation error

android/app/src/main/java/com/wix/reactnativenotifications/core/notification/PushNotification.java

@@ -151,11 +151,18 @@ protected Notification.Builder getNotificationBuilder(PendingIntent intent) {
         final Notification.Builder notification = new Notification.Builder(mContext)
                 .setContentTitle(mNotificationProps.getTitle())
                 .setContentText(mNotificationProps.getBody())
-                .setSmallIcon(mContext.getApplicationInfo().icon)
                 .setContentIntent(intent)
                 .setDefaults(Notification.DEFAULT_ALL)
                 .setAutoCancel(true);
 
+
+             int resourceID = mContext.getResources().getIdentifier("notification_icon", "drawable", mContext.getPackageName());
+                if (resourceID != 0) {
+                    notification.setSmallIcon(resourceID);
+                } else {
+                    notification.setSmallIcon(mContext.getApplicationInfo().icon);
+                }
+
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             NotificationChannel channel = new NotificationChannel(CHANNEL_ID,
                     CHANNEL_NAME,

android/app/src/reactNative59/java/com/wix/reactnativenotifications/NotificationManagerCompatFacade.java

@@ -2,7 +2,7 @@
 package com.wix.reactnativenotifications;
 
 import android.content.Context;
-import android.support.annotation.Nullable;
+import android.support.annotation.NonNull;
 import android.support.v4.app.NotificationManagerCompat;
 
 public abstract class NotificationManagerCompatFacade {

docs/installation.md

@@ -183,4 +183,13 @@ To do so edit `android/build.gradle` and add:
 +}
 ```
 
-**Note**: As more build variants come available in the future, you will need to adjust the list (`names.contains("reactNative59")`). This is why we recommend the first solution.
+**Note**: As more build variants come available in the future, you will need to adjust the list (`names.contains("reactNative59")`). This is why we recommend the first solution.
+
+#### Step #6: Set your notification Icon.
+
+By default, the package will use your native application icon. If your icon is not notification friendly, you may have to set and use a different icon. To do this, create a notification_icon.png and add it to your drawable folders. Once that is done add the following line to your AndroidManifest.xml
+
+```diff
++<meta-data android:name="com.google.firebase.messaging.default_notification_icon" android:resource="@drawable notification_icon" />
+```
+