If I did not pick any image it will have an error message-CodePudding

I want to upload an image in firebase storage using flutter, but when I did not choose any image there will be an error.

The error started to happen when I put the code that will upload the image. If I also remove the null check, it will also show an error message that it needs a null check.

        import 'package:file_picker/file_picker.dart';
    import 'package:flutter/material.dart';
    import 'package:project/storage_service.dart';

    class UserProfile extends StatefulWidget {
      const UserProfile({super.key});

      @override
      State<UserProfile> createState() => _UserProfileState();
    }

    class _UserProfileState extends State<UserProfile> {
      @override
      Widget build(BuildContext context) {
        final Storage storage = Storage();
        return Scaffold(
          appBar: AppBar(
            title: Text('Profile Picture'),
          ),
          body: Column(
            children: [
              Center(
                  child: ElevatedButton(
                      onPressed: () async {
                        final results = await FilePicker.platform.pickFiles(
                          allowMultiple: false,
                          type: FileType.custom,
                          allowedExtensions: ['png', 'jpg'],
                        );

                        if (results == null) {
                          ScaffoldMessenger.of(context).showSnackBar(
                              const SnackBar(content: Text('No selected file.')));
                        }

                        final path = results?.files.single.path;
                        final fileName = results?.files.single.name;

                        // when I added this line of code there will be an error when I did not choose any image
                        storage
                            .uploadFile(path!, fileName!)
                            .then((value) => print('done'));
                      },
                      child: Text('Upload profile picture')))
            ],
          ),
        );
      }
    }

CodePudding user response：

if (results == null) {
                  ScaffoldMessenger.of(context).showSnackBar(
                      const SnackBar(content: Text('No selected file.')));
                } else {
                  final path = results.files.single.path;
                  final fileName = results.files.single.name;

                  print(path);
                  print(fileName);
                  storage
                      .uploadFile(path!, fileName)
                      .then((value) => print('done'));
                }
              },

CodePudding user response：

To add to Bart's answer: As the error message is currently missing in the question, I can only guess that it has todo with the forced optional unwrapping (!) in this function call

storage
    .uploadFile(path!, fileName!)
    .then((value) => print('done'));

You should check these values for null before accessing them.