Default using drawable as Android small icon

Author: hojason117

android/src/main/java/com/dieam/reactnativepushnotification/modules/RNPushNotificationHelper.java

@@ -319,9 +319,12 @@ public void sendToNotificationCentreWithPicture(Bundle bundle, Bitmap largeIconB
             String smallIcon = bundle.getString("smallIcon");
 
             if (smallIcon != null && !smallIcon.isEmpty()) {
-              smallIconResId = res.getIdentifier(smallIcon, "mipmap", packageName);
+                smallIconResId = res.getIdentifier(smallIcon, "drawable", packageName);
+                if (smallIconResId == 0) {
+                    smallIconResId = res.getIdentifier(smallIcon, "mipmap", packageName);
+                }
             } else if(smallIcon == null) {
-              smallIconResId = res.getIdentifier("ic_notification", "mipmap", packageName);
+                smallIconResId = res.getIdentifier("ic_notification", "mipmap", packageName);
             }
 
             if (smallIconResId == 0) {
@@ -341,9 +344,9 @@ public void sendToNotificationCentreWithPicture(Bundle bundle, Bitmap largeIconB
                 String largeIcon = bundle.getString("largeIcon");
 
                 if (largeIcon != null && !largeIcon.isEmpty()) {
-                  largeIconResId = res.getIdentifier(largeIcon, "mipmap", packageName);
+                    largeIconResId = res.getIdentifier(largeIcon, "mipmap", packageName);
                 } else if(largeIcon == null) {
-                  largeIconResId = res.getIdentifier("ic_launcher", "mipmap", packageName);
+                    largeIconResId = res.getIdentifier("ic_launcher", "mipmap", packageName);
                 }
 
                 // Before Lolipop there was no large icon for notifications.