code: public Map<String, Reflector> fields() {
          Map<String, Reflector> result;
          if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
              result = new ArrayMap<>();
          } else {
              result = new HashMap<>();
          }
          Class<?> type = type();
          do {
              // all field
              for (Field field : type.getDeclaredFields()) {
                  if (!isClass ^ Modifier.isStatic(field.getModifiers())) {
                      String name = field.getName();
                      // add
                      if (!result.containsKey(name))
                          result.put(name, field(name));
                  }
              }
  
              type = type.getSuperclass();
          }
          while (type != null);
  
          return result;
      }
docs: Get current {@link Reflector#obj} fields by create Map
  
  @return a map to Reflector-fields