i am getting this error Null check operator used on a null value ? from the line imageList! how to solve this thank you in advance using late modifier bring another error LateInitializationError: Field 'imageList' has not been initialized.

class SliderView extends StatefulWidget {
  const SliderView({Key? key}) : super(key: key);

  @override
  State<SliderView> createState() => _SliderViewState();
}

class _SliderViewState extends State<SliderView> {
  List? imageList;
  bool loading = true;
  String imageFolder = "http://192.168.1.72/flutterverify/upload/";

  fetchSlider() async {
    final response = await http
        .get(Uri.parse("http://192.168.1.72/flutterverify/slider.php"));
    if (response.statusCode == 200) {
      setState(() {
        imageList = jsonDecode(response.body);
        loading = false;
      });
    }
    print(imageList);
  }

  @override
  void initState() {
    imageList;
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("SLider"),
      ),
      body: Container(
        child: Carousel(
            boxFit: BoxFit.cover,
            autoplay: false,
            animationCurve: Curves.fastOutSlowIn,
            animationDuration: Duration(milliseconds: 1000),
            dotSize: 6.0,
            dotIncreasedColor: Color(0xFFFF335C),
            dotBgColor: Colors.transparent,
            dotPosition: DotPosition.topRight,
            dotVerticalPadding: 10.0,
            showIndicator: true,
            indicatorBgPadding: 7.0,
            images: imageList!.map((element) {
              return new Image.network(imageFolder   element['image']);
            }).toList()),
      ),
    );
  }
} ```

CodePudding user response：

It is a null safety error, The imageList is set from a http.get which can be null, so replace this:

if (response.statusCode == 200) {
      setState(() {
        imageList = jsonDecode(response.body);
        loading = false;
      });
   }

By this

if (response.statusCode == 200) {
      setState(() {
        imageList = jsonDecode(response.body ?? '[]');
        loading = false;
      });
   }

Doing this you affect by default an empty array to imageList in case of null value.

CodePudding user response：

You need to change rows that i mentioned below:

print(imageList); =>  print(imageList!);

and this block

   @override
      void initState() {
        imageList; => imageList!;
        super.initState();
      }