Flutter: Bad state Error: cannot get a field on a DocumentSnapshotPlatform which does not exist - flutter

Question

I'm new to Flutter and getting this issue.
Trying to develop a social media app which includes a chat feature. However, it says DocumentSnapshot is not exist.
Of course I understood that one thing is missing, it is clear. But I couldn't understand what is that missing thing and how to solve it.
I examined a lot of posts about this but I couldn't solve my issue. There is no misspelling between Cloud Firestore and my code. I couldn't understand am I missing key or something like this?
It looks like this
Sometimes it also can not upload the profile picture of person.
Here are my codes,
Thanks for helping.
I got this error when I try to type a message:
class Conversation extends StatefulWidget {
final String userId;
final String chatId;
const Conversation({required this.userId, required this.chatId});
#override
_ConversationState createState() => _ConversationState();
}
class _ConversationState extends State<Conversation> {
FocusNode focusNode = FocusNode();
ScrollController scrollController = ScrollController();
TextEditingController messageController = TextEditingController();
bool isFirst = false;
String? chatId;
#override
void initState() {
super.initState();
scrollController.addListener(() {
focusNode.unfocus();
});
print(widget.chatId);
if (widget.chatId == 'newChat') {
isFirst = true;
}
chatId = widget.chatId;
messageController.addListener(() {
if (focusNode.hasFocus && messageController.text.isNotEmpty) {
setTyping(true);
} else if (!focusNode.hasFocus ||
(focusNode.hasFocus && messageController.text.isEmpty)) {
setTyping(false);
}
});
}
setTyping(typing) {
//here
UserViewModel viewModel =
Provider.of<UserViewModel>(context, listen: false);
viewModel.setUser();
//here
var user = Provider.of<UserViewModel>(context, listen: false).user;
Provider.of<ConversationViewModel>(context, listen: false)
.setUserTyping(widget.chatId, user, typing);
}
#override
Widget build(BuildContext context) {
UserViewModel viewModel =
Provider.of<UserViewModel>(context, listen: false);
viewModel.setUser();
var user = Provider.of<UserViewModel>(context, listen: true).user;
return Consumer<ConversationViewModel>(
builder: (BuildContext context, viewModel, Widget? child) {
return Scaffold(
key: viewModel.scaffoldKey,
appBar: AppBar(
leading: GestureDetector(
onTap: () {
Navigator.pop(context);
},
child: Icon(
Icons.keyboard_backspace,
),
),
elevation: 0.0,
titleSpacing: 0,
title: buildUserName(),
),
body: Container(
height: MediaQuery.of(context).size.height,
child: Column(
children: [
Flexible(
child: StreamBuilder<QuerySnapshot>(
stream: messageListStream(widget.chatId),
builder: (context, snapshot) {
if (snapshot.hasData) {
//snapshot.hasData
//print(snapshot.data);
print(viewModel);
List messages = snapshot.data!.docs;
viewModel.setReadCount(
widget.chatId, user, messages.length);
return ListView.builder(
controller: scrollController,
padding: EdgeInsets.symmetric(horizontal: 10.0),
itemCount: messages.length,
reverse: true,
itemBuilder: (BuildContext context, int index) {
Message message = Message.fromJson(
messages.reversed.toList()[index].data(),
);
print(message.content);
print(message.senderUid);
print(message.time);
print(message.type);
return ChatBubble(
message: '${message.content}',
time: message.time!,
isMe: message.senderUid == user!.uid,
type: message.type!,
);
},
);
} else {
return Center(child: circularProgress(context));
}
},
),
),
Align(
alignment: Alignment.bottomCenter,
child: BottomAppBar(
elevation: 10.0,
child: Container(
constraints: BoxConstraints(maxHeight: 100.0),
child: Row(
crossAxisAlignment: CrossAxisAlignment.end,
children: [
IconButton(
icon: Icon(
CupertinoIcons.photo_on_rectangle,
color: Theme.of(context).colorScheme.secondary,
),
onPressed: () => showPhotoOptions(viewModel, user),
),
Flexible(
child: TextField(
controller: messageController,
focusNode: focusNode,
style: TextStyle(
fontSize: 15.0,
color:
Theme.of(context).textTheme.headline6!.color,
),
decoration: InputDecoration(
contentPadding: EdgeInsets.all(10.0),
enabledBorder: InputBorder.none,
border: InputBorder.none,
hintText: "Type your message",
hintStyle: TextStyle(
color: Theme.of(context)
.textTheme
.headline6!
.color,
),
),
maxLines: null,
),
),
IconButton(
icon: Icon(
Ionicons.send,
color: Theme.of(context).colorScheme.secondary,
),
onPressed: () {
if (messageController.text.isNotEmpty) {
sendMessage(viewModel, user);
}
},
),
],
),
),
),
)
],
),
),
);
});
}
_buildOnlineText(
var user,
bool typing,
) {
if (user.isOnline) {
if (typing) {
return "typing...";
} else {
return "online";
}
} else {
return 'last seen ${timeago.format(user.lastSeen.toDate())}';
}
}
buildUserName() {
return StreamBuilder(
stream: usersRef.doc('${widget.userId}').snapshots(),
builder: (context, snapshot) {
if (snapshot.hasData) {
DocumentSnapshot documentSnapshot =
snapshot.data as DocumentSnapshot<Object?>;
UserModel user = UserModel.fromJson(
documentSnapshot.data() as Map<String, dynamic>,
);
return InkWell(
child: Row(
children: <Widget>[
Padding(
padding: EdgeInsets.only(left: 10.0, right: 10.0),
child: Hero(
tag: user.email!,
child: CircleAvatar(
radius: 25.0,
backgroundImage: CachedNetworkImageProvider(
'${user.photoUrl}',
),
),
),
),
SizedBox(width: 10.0),
Expanded(
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Text(
'${user.username}',
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 15.0,
),
),
SizedBox(height: 5.0),
StreamBuilder(
stream: chatRef.doc('${widget.chatId}').snapshots(),
builder: (context, snapshot) {
if (snapshot.hasData) {
DocumentSnapshot? snap =
snapshot.data as DocumentSnapshot<Object?>;
Map? data = snap.data() as Map<dynamic, dynamic>?;
Map? usersTyping = data?['typing'] ?? {};
return Text(
_buildOnlineText(
user,
usersTyping![widget.userId] ?? false,
),
style: TextStyle(
fontWeight: FontWeight.w400,
fontSize: 11,
),
);
} else {
return SizedBox();
}
},
),
],
),
),
],
),
onTap: () {},
);
} else {
return Center(child: CircularProgressIndicator());
}
},
);
}
showPhotoOptions(ConversationViewModel viewModel, var user) {
showModalBottomSheet(
context: context,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.all(
Radius.circular(10.0),
),
),
builder: (context) {
return Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
ListTile(
title: Text("Camera"),
onTap: () {
sendMessage(viewModel, user, imageType: 0, isImage: true);
},
),
ListTile(
title: Text("Gallery"),
onTap: () {
sendMessage(viewModel, user, imageType: 1, isImage: true);
},
),
],
);
},
);
}
sendMessage(ConversationViewModel viewModel, var user,
{bool isImage = false, int? imageType}) async {
String msg;
if (isImage) {
msg = await viewModel.pickImage(
source: imageType!,
context: context,
chatId: widget.chatId,
);
} else {
msg = messageController.text.trim();
messageController.clear();
}
Message message = Message(
content: '$msg',
senderUid: user?.uid,
type: isImage ? MessageType.IMAGE : MessageType.TEXT,
time: Timestamp.now(),
);
if (msg.isNotEmpty) {
if (isFirst) {
print("FIRST");
String id = await viewModel.sendFirstMessage(widget.userId, message);
setState(() {
isFirst = false;
chatId = id;
});
} else {
viewModel.sendMessage(
widget.chatId,
message,
);
}
}
}
Stream<QuerySnapshot> messageListStream(String documentId) {
return chatRef
.doc(documentId)
.collection('messages')
.orderBy('time')
.snapshots();
}
}
Also here is the ViewModel codes if I did something wrong here:
class ConversationViewModel extends ChangeNotifier {
GlobalKey<ScaffoldState> scaffoldKey = GlobalKey<ScaffoldState>();
ChatService chatService = ChatService();
bool uploadingImage = false;
final picker = ImagePicker();
File? image;
sendMessage(String chatId, Message message) {
chatService.sendMessage(
message,
chatId,
);
}
Future<String> sendFirstMessage(String recipient, Message message) async {
String newChatId = await chatService.sendFirstMessage(
message,
recipient,
);
return newChatId;
}
setReadCount(String chatId, var user, int count) {
chatService.setUserRead(chatId, user, count);
}
setUserTyping(String chatId, var user, bool typing) {
chatService.setUserTyping(chatId, user, typing);
}
pickImage({int? source, BuildContext? context, String? chatId}) async {
PickedFile? pickedFile = source == 0
? await picker.getImage(
source: ImageSource.camera,
)
: await picker.getImage(
source: ImageSource.gallery,
);
if (pickedFile != null) {
CroppedFile? croppedFile = await ImageCropper().cropImage(
sourcePath: pickedFile.path,
aspectRatioPresets: [
CropAspectRatioPreset.square,
CropAspectRatioPreset.ratio3x2,
CropAspectRatioPreset.original,
CropAspectRatioPreset.ratio4x3,
CropAspectRatioPreset.ratio16x9
],
uiSettings: [
AndroidUiSettings(
toolbarTitle: 'Crop image',
toolbarColor: Theme.of(context!).appBarTheme.backgroundColor,
toolbarWidgetColor: Theme.of(context).iconTheme.color,
initAspectRatio: CropAspectRatioPreset.original,
lockAspectRatio: false,
),
IOSUiSettings(
minimumAspectRatio: 1.0,
),
],
);
Navigator.of(context).pop();
if (croppedFile != null) {
uploadingImage = true;
image = File(croppedFile.path);
notifyListeners();
showInSnackBar("Uploading image...", context);
String imageUrl = await chatService.uploadImage(image!, chatId!);
return imageUrl;
}
}
}
void showInSnackBar(String value, context) {
ScaffoldMessenger.of(context).removeCurrentSnackBar();
ScaffoldMessenger.of(context).showSnackBar(
SnackBar(
content: Text(value),
),
);
}
}
Here is the ChatService code:
class ChatService {
FirebaseStorage storage = FirebaseStorage.instance;
sendMessage(Message message, String chatId) async {
//will send message to chats collection with the usersId
await chatRef.doc("$chatId").collection("messages").add(message.toJson());
//will update "lastTextTime" to the last time a text was sent
await chatRef.doc("$chatId").update({"lastTextTime": Timestamp.now()});
}
Future<String> sendFirstMessage(Message message, String recipient) async {
User user = firebaseAuth.currentUser!;
DocumentReference ref = await chatRef.add({
'users': [recipient, user.uid],
});
await sendMessage(message, ref.id);
return ref.id;
}
Future<String> uploadImage(File image, String chatId) async {
Reference storageReference =
storage.ref().child("chats").child(chatId).child(uuid.v4());
UploadTask uploadTask = storageReference.putFile(image);
await uploadTask.whenComplete(() => null);
String imageUrl = await storageReference.getDownloadURL();
return imageUrl;
}
//determine if a user has read a chat and updates how many messages are unread
setUserRead(String chatId, User user, int count) async {
DocumentSnapshot snap = await chatRef.doc(chatId).get();
Map reads = snap.get('reads') ?? {};
reads[user.uid] = count;
await chatRef.doc(chatId).update({'reads': reads});
}
//determine when a user has start typing a message
setUserTyping(String chatId, User user, bool userTyping) async {
DocumentSnapshot snap = await chatRef.doc(chatId).get();
Map typing = snap.get('typing');
typing[user.uid] = userTyping;
await chatRef.doc(chatId).update({
'typing': typing,
});
}
}