code: public static int optInt(@Nullable Bundle bundle, @Nullable String key) {
          return optInt(bundle, key, 0);
      }
docs: Returns a optional int value. In other words, returns the value mapped by key if it exists and is a int.
  The bundle argument is allowed to be {@code null}. If the bundle is null, this method returns 0.
  @param bundle a bundle. If the bundle is null, this method will return 0.
  @param key a key for the value.
  @return a int value if exists, 0 otherwise.
  @see android.os.Bundle#getInt(String)