我需要当用户点击按钮添加数据到firebase，蛇栏弹出一个成功的消息，然后返回。但没有导航发生。

使用navigator时出现的错误是：

对空值使用空检查运算符时出错

验证码为：

class AddProductController extends GetxController {
 
  addProduct() async {
    if ((addProductFormKey.currentState?.validate() ?? false) &&
        pickedPhoto != null) {
      String docID = FirebaseFirestore.instance.collection('products').doc().id;
      var url = "";
      try {
        UploadTask uploadTask = FirebaseStorage.instance
            .ref('users/products/$docID/')
            .putFile(pickedPhoto!);
        uploadTask.whenComplete(() async {
          url = await FirebaseStorage.instance
              .ref('users/products/$docID/')
              .getDownloadURL();
          await FirebaseFirestore.instance
              .collection("products")
              .doc(docID)
              .set({
            "imgUrl": url,
          }, SetOptions(merge: true));
          Get.snackbar(
            "Sucess",
            "Your Product Is Added",
            snackPosition: SnackPosition.BOTTOM,
          );
        }).catchError((onError) {
          print(onError);
        });

        return Get.toNamed(Routes.PRODUCTS); // => doees not work
      } catch (e) {
        print("\n Error $e \n");
      }
    }
  }
}