Why I cannot use NetworkImage in flutter? I got the error. Which one was I missed?

in my code

Stack(
                children: [
                  _image != null
                      ? CircleAvatar(
                          radius: 64,
                          backgroundImage: MemoryImage(_image!),
                        )
                      : const CircleAvatar(
                          radius: 64,
                          backgroundImage: NetworkImage(user.userimage),
                        ),
                  Positioned(
                      bottom: -10,
                      left: 80,
                      child: IconButton(
                        onPressed: selectImage,
                        icon: const Icon(Icons.add_a_photo),
                      ))
                ],
              ),

But I got this error code

and this

A value of type 'Null' can't be assigned to a parameter of type 'String' in a const constructor. Try using a subtype, or removing the keyword 'const'.

the image from FirebaseStorage

CodePudding user response：

• firstly you must check the image url is correct or not
• and can use "Image.network" that already Inheritance from "NetworkImage"

and i changed your code to be like below , please try it :

const CircleAvatar(
                          radius: 64,
                          child: Image.network(
                                          user.userimage,
                                          fit: BoxFit.fill,
                                          errorBuilder:
                                              (context, error, stackTrace) {
                                            return Image.asset(
                                                'put and image here');
                                          },
                                        )
                        ),