I am a newbie in fetching data from APIs

I have an api endpoint containing two query params and also having a body of string and int. I want to make an already existing post to be featured on the home page with time limit.

in my repo I have written this

class FeaturePost {
  Future featurePost(int duration, String period) async {
    SharedPreferences preferences = await SharedPreferences.getInstance();
    var token = preferences.getString('token').toString();
    final queryParameters = {
      'postpId': 'postId',
      'id': 'id',
    };
http.post(Uri.dataFromString("https/url.com/api/v1/post?" parameters: queryParameters),
        headers: {
          'Content-Type': 'application/json',
          'x-access-token': token,
        },
        body: {
          "duration": duration,
          "period": period
        });

here's my button

                                                   GestureDetector(
                                                    onTap: () async {
                                                      setState(() {
                                                        period =
                                                            "${dropdownValue}";
                                                      });
                                                      if (_postKey
                                                          .currentState!
                                                          .validate()) {
                                                        var create =
                                                            PostModel(
                                                          postId:
                                                              widget.postId,
                                                          id: widget.userId,
                                                          period: period,
                                                          duration: int.parse(
                                                              durationController
                                                                  .text),
                                                        );
                                                        createPost
                                                            .newPostDuration(
                                                          create,
                                                          widget.postId,
                                                        );
                                                      }
                                                    },
                                                    child: Center(
                                                        child: Text('Make Post Featured',),
                                                      
                                                    ),
                                                  )

my controller

class FeaturePostController extends GetxController {
  final featureAPostRepo = FeaturePost();

  Future<dynamic> newFeaturedPost(ostpId, id) async {
    try {
      final result = await featureAnAdRepo.featureAnAd(postId, id);
      Get.back();
      await fromFeaturedAds.fetchFeaturedAds();
      // Get.snackBar('Success', 'Post Featured Successfully');

      print(result);
      return result;
    } catch (e) {
      throw Exception(e);
    }
  }
}

this is the response i get Unhandled Exception: Null check operator used on a null value.

CodePudding user response：

Since you're getting Null check operator used on a null value exception, it's probably because you haven't assigned your _postKey to the form that you are trying to validate. Make sure you're wrapping all your fields inside a form and that your key is assigned to the key parameter of that form

CodePudding user response：

I was able to fix it. It was because I wasn't parsing all required params properly. All I had to do was add "postId" and "Id" like this ```featurePost(String postId, String Id, int duration, String period) and some rearrangements and it worked