在向 email 注册时将用户头像图像上传到 firebase 时，在使用 getter 获取 ImageUrl 时会给出 null 值

Question

So I am trying to upload user avatar to firebase storage while registering to firebase auth with email and password and simultaneously adding it to cloud firestore, but the image I upload using imageFilePicker returns null when trying to get it. I am using provider for state management. I am new to this.

Image Upload code:

class FirebaseOperations with ChangeNotifier {
 UploadTask imageUploadTask;
 String initUserEmail, initUserName, initUserImage;
 String get getInitUserName => initUserName;
 String get getInitUserEmail => initUserEmail;
 String get getInitUserImage => initUserImage;

 Future uploadUserAvatar(BuildContext context) async {
Reference imageReference = FirebaseStorage.instance
    .ref()
    .child('userProfileAvatar/${DateTime.now()}');
imageUploadTask = imageReference.putFile(
    Provider.of<ImageSelect>(context, listen: false).getUserAvatar);
await imageUploadTask.whenComplete(() {
  print('Image uploaded!');
});
imageReference.getDownloadURL().then((url) {
  print("################################################" + url);
  Provider.of<ImageSelect>(context, listen: false).userAvatarUrl =
      url.toString();
  print(
      'the user profile avatar url => ${Provider.of<ImageSelect>(context, listen: false).userAvatarUrl}');
  notifyListeners();
});
}
 Future initUserData(BuildContext context) async {
   return FirebaseFirestore.instance
    .collection('users')
    .doc(Provider.of<Authentication>(context, listen: false).getUserUid)
    .get()
    .then((doc) {
  print('Fetching user data');

  initUserName = doc.data()['username'];
  initUserEmail = doc.data()['useremail'];
  initUserImage = doc.data()['userimage'];
  print(initUserName);
  print(initUserEmail);
  print(initUserImage);
  notifyListeners();
});
}
}  

Image select code:

class ImageSelect with ChangeNotifier {
final picker = ImagePicker();
File userAvatar;
File get getUserAvatar => userAvatar;
String userAvatarUrl;
String get getUserAvatarUrl => userAvatarUrl;

Future pickUserAvatar(BuildContext context, ImageSource source) async {
final pickedUserAvatar = await picker.getImage(source: source);
pickedUserAvatar == null
    ? print('Select image')
    : userAvatar = File(pickedUserAvatar.path);
// print(userAvatar.path);
if (userAvatar != null) {
  await Provider.of<FirebaseOperations>(context, listen: false)
      .uploadUserAvatar(context);
} else
  print('Image not Selected ');
notifyListeners();
}

Register Button code:

GestureDetector(
            onTap: () {
              if (_emailController.text.isNotEmpty) {
                Provider.of<Authentication>(context, listen: false)
                    .createAccount(
                        _emailController.text, _passwordController.text)
                    .whenComplete(() {
                 
                  print('Creating collection...');
                  Provider.of<FirebaseOperations>(context, listen: false)
                      .createUserCollection(context, {
                    'userpassword': _passwordController.text,
                    'useruid':
                        Provider.of<Authentication>(context, listen: false)
                            .getUserUid,
                    'useremail': _emailController.text,
                    'username': _fullNameController.text,
                    'usermobile': _phoneNumberController.text,
                    'userimage':
                        Provider.of<ImageSelect>(context, listen: true)
                            .getUserAvatarUrl,
                  });
                }).whenComplete(() {
                  Navigator.pushReplacement(
                      context,
                      MaterialPageRoute(
                          builder: (context) => HomeScreen()));
                });
              } else {
                warningText(context, 'Fill all the data!');
              }
            },

Error Code:

I/flutter (30433): Image uploaded!
I/flutter (30433): 
################################################https://firebasestorage.googleapis.com/v0/b/bubblez-        
e2801.appspot.com/o/userProfileAvatar%2F2021-03-25%2011%3A34%3A39.688986?alt=media&token=78a2be55- 
b45c-453e-a398-02a363178d9d
E/flutter (30433): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: Looking up a 
deactivated widget's ancestor is unsafe.
E/flutter (30433): At this point the state of the widget's element tree is no longer stable.
E/flutter (30433): To safely refer to a widget's ancestor in its dispose() method, save a reference 
to the ancestor by calling dependOnInheritedWidgetOfExactType() in the widget's 
didChangeDependencies() method.
E/flutter (30433): #0      Element._debugCheckStateIsActiveForAncestorLookup.<anonymous closure>
package:flutter/…/widgets/framework.dart:3864
E/flutter (30433): #1      Element._debugCheckStateIsActiveForAncestorLookup
 package:flutter/…/widgets/framework.dart:3878
E/flutter (30433): #2      Element.getElementForInheritedWidgetOfExactType
package:flutter/…/widgets/framework.dart:3905
E/flutter (30433): #3      Provider._inheritedElementOf
package:provider/src/provider.dart:327
E/flutter (30433): #4      Provider.of
package:provider/src/provider.dart:284
E/flutter (30433): #5      FirebaseOperations.uploadUserAvatar.<anonymous closure>
package:bubblez/…/authMethods/FirebaseOperations.dart:27
E/flutter (30433): #6      _rootRunUnary (dart:async/zone.dart:1362:47)
E/flutter (30433): #7      _CustomZone.runUnary (dart:async/zone.dart:1265:19)
E/flutter (30433): #8      _FutureListener.handleValue (dart:async/future_impl.dart:152:18)
E/flutter (30433): #9      Future._propagateToListeners.handleValueCallback 
(dart:async/future_impl.dart:704:45)
E/flutter (30433): #10     Future._propagateToListeners (dart:async/future_impl.dart:733:32)
E/flutter (30433): #11     Future._completeWithValue (dart:async/future_impl.dart:539:5)
E/flutter (30433): #12     _completeOnAsyncReturn (dart:async-patch/async_patch.dart:254:13)
E/flutter (30433): #13     MethodChannelReference.getDownloadURL 
(package:firebase_storage_platform_interface/src/method_channel/method_channel_reference.dart)
package:firebase_storage_platform_interface/…/method_channel/method_channel_reference.dart:1
E/flutter (30433): <asynchronous suspension>
E/flutter (30433):

I/flutter (30433): Fetching user data
E/flutter (30433): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: 
NoSuchMethodError: The method '[]' was called on null.
E/flutter (30433): Receiver: null
 E/flutter (30433): Tried calling: []("username")
 E/flutter (30433): #0      Object.noSuchMethod (dart:core-patch/object_patch.dart:54:5)
E/flutter (30433): #1      FirebaseOperations.initUserData.<anonymous closure>
package:bubblez/…/authMethods/FirebaseOperations.dart:50
E/flutter (30433): #2      _rootRunUnary (dart:async/zone.dart:1362:47)

Answer 1

Your problem is in this function

Future initUserData(BuildContext context) async {
   return FirebaseFirestore.instance
    .collection('users')
    .doc(Provider.of<Authentication>(context, listen: false).getUserUid)
    .get()
    .then((doc) {
  print('Fetching user data')});}

Because in your debug console, I read the line saying Image uploaded! , can you confirm that an Image URL and username have been posted to firestore?

Try changing it to this:

 Future initUserData(BuildContext context) async {
  return await FirebaseFirestore.instance //<=== adding await here
 .collection('users')
 .doc(Provider.of<Authentication>(context, listen: false).getUserUid)
 .get()
 .then((doc) {
  initUserName = doc.data()['username'];
  initUserEmail = doc.data()['useremail'];
  initUserImage = doc.data()['userimage'];
  print(initUserName);
  print(initUserEmail);
  print(initUserImage);
  notifyListeners();
});
}

And update on what happens. Because your error log also says that ['username'] was called on null, which is only the first one of your inquires, it's not reaching the point to image or email.

If this doesn't work, we can try working with the BuildContext that is being passed to your provider functions.