Function can't be unconditionally invoked because it can be 'null'

Question

I am building a profile page. But I am having some issues in retrieving name and mail from the firebase.

 firebase_auth: ^3.1.1
 firebase_core: ^1.6.0
 google_sign_in: ^5.1.0
 firebase_storage: ^10.0.3
 cloud_firestore: ^2.5.3
 firebase_analytics: ^8.3.2
 lottie: ^1.1.0
 image_picker: ^0.8.4

Above is my pubspec.yaml dependencies.

  Widget headerProfile(
  BuildContext context, AsyncSnapshot<DocumentSnapshot> snapshot) {
  return SizedBox(
  height: MediaQuery.of(context).size.height * 0.26,
  width: MediaQuery.of(context).size.width,
  child: Row(
    mainAxisAlignment: MainAxisAlignment.spaceEvenly,
    children: [
      Container(
        height: 150.0,
        width: 170.0,
        child: Column(
          children: [
            GestureDetector(
              onTap: () {},
              child: CircleAvatar(
                backgroundColor: constantColors.transparent,
                radius: 38.0,
                backgroundImage: NetworkImage(
                    '${Provider.of<FirebaseOperations>(context).getInitUserImage}'),
              ),
            ),
            Padding(
              padding: const EdgeInsets.only(top: 8.0),
              child: Text(
                snapshot.data()['username'],
                style: TextStyle(
                    color: constantColors.whiteColor,
                    fontWeight: FontWeight.bold,
                    fontSize: 20.0),
              ),
            ),

Above is the profilehelpers.dart page.

 class Profile extends StatefulWidget {
 @override
 _ProfileState createState() => _ProfileState();
 }

class _ProfileState extends State<Profile> {
final ConstantColors constantColors = ConstantColors();
 @override
 Widget build(BuildContext context) {
return Scaffold(
  appBar: AppBar(
    centerTitle: true,
    leading: IconButton(
      onPressed: () {},
      icon: Icon(EvaIcons.settings2Outline,
          color: constantColors.lightBlueColor),
    ),
    actions: [
      IconButton(
          icon: Icon(EvaIcons.logOutOutline,
              color: constantColors.greenColor),
          onPressed: () {
            Provider.of<ProfileHelpers>(context, listen: false)
                .logOutDialog(context);
          })
    ],
    backgroundColor: constantColors.blueGreyColor.withOpacity(0.4),
    title: RichText(
      text: TextSpan(
          text: 'My ',
          style: TextStyle(
            color: constantColors.whiteColor,
            fontWeight: FontWeight.bold,
            fontSize: 20.0,
          ),
          children: <TextSpan>[
            TextSpan(
                text: 'Profile',
                style: TextStyle(
                  color: constantColors.blueColor,
                  fontWeight: FontWeight.bold,
                  fontSize: 20.0,
                ))
          ]),
       ),
      ),
    body: SingleChildScrollView(
    child: Padding(
      padding: const EdgeInsets.all(8.0),
      child: Container(
        height: MediaQuery.of(context).size.height,
        width: MediaQuery.of(context).size.width,
       
        child: StreamBuilder<DocumentSnapshot<Map<String, dynamic>>>(
          stream: FirebaseFirestore.instance
              .collection('users')
              .doc(Provider.of<Authentication>(context, listen: false)
                  .getUserUid)
              .snapshots(),
          builder: (BuildContext context,
              AsyncSnapshot<DocumentSnapshot> snapshot) {
            if (snapshot.connectionState == ConnectionState.waiting) {
              return Center(
                child: CircularProgressIndicator(),
              );
            } else {
              return new Column(
                children: [
                  Provider.of<ProfileHelpers>(context, listen: false)
                      .headerProfile(context, snapshot),
                  Provider.of<ProfileHelpers>(context, listen: false)
                      .divider(),
                  Provider.of<ProfileHelpers>(context, listen: false)
                      .middleProfile(context, snapshot),
                  Provider.of<ProfileHelpers>(context, listen: false)
                      .footerProfile(context, snapshot)
                ],
              );
            }
          },
        ),
        decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(15.0),
            color: constantColors.blueGreyColor.withOpacity(0.6)),
      ),
    ),
     ),
    );
    }
    }

Above is the profile.dart file code. I think the problem is somewhere with document and asyncsnapshot and 'snapshot.data()['username']'.If someone can point out my mistake it will be more helpful for me.

40:34: Error: 'data' isn't a function or method and can't be 
  invoked.
                snapshot.data()['username'],
                             ^^^^


FAILURE: Build failed with an exception.

This is the error I am getting

please also post your console after run. it would be helpful to find the problem — Taqi Tahmid Tanzil, Sep 18 '21 at 05:06
Sorry for the inconvenience. I have added the error status above. — Aswin B, Sep 18 '21 at 05:19
Try This, From : snapshot.data()['username'], To : snapshot.data['username'], Check This : https://stackoverflow.com/questions/64792658/error-currentuser-isnt-a-function-or-method-and-cant-be-invoked — Yashraj, Sep 18 '21 at 05:31
snapshot.data['username'], didn't work,as it showing 'The method '[]' can't be unconditionally invoked because the receiver can be 'null'. ' — Aswin B, Sep 18 '21 at 05:49

Peter Obiechina · Accepted Answer · 2021-09-18T06:22:06.987

0

Should be snapshot.data.data()['username'] not snapshot.data()['username'];

You may still get errors (like Object not being a subtype of Map) because of the way you wrote your code, in that case, use this (copy and paste into your code, I changed some things):

Widget headerProfile(
  BuildContext context, AsyncSnapshot<DocumentSnapshot<Map<String, dynamic>>> snapshot) {
  Map<String, dynamic>? map = snapshot.data!.data();
  return SizedBox(
  height: MediaQuery.of(context).size.height * 0.26,
  width: MediaQuery.of(context).size.width,
  child: Row(
    mainAxisAlignment: MainAxisAlignment.spaceEvenly,
    children: [
      Container(
        height: 150.0,
        width: 170.0,
        child: Column(
          children: [
            GestureDetector(
              onTap: () {},
              child: CircleAvatar(
                backgroundColor: constantColors.transparent,
                radius: 38.0,
                backgroundImage: NetworkImage(
                    '${Provider.of<FirebaseOperations>(context).getInitUserImage}'),
              ),
            ),
            Padding(
              padding: const EdgeInsets.only(top: 8.0),
              child: Text(
                map['username'],
                style: TextStyle(
                    color: constantColors.whiteColor,
                    fontWeight: FontWeight.bold,
                    fontSize: 20.0),
              ),
            ),

edited Sep 18 '21 at 06:22

answered Sep 18 '21 at 05:32

Peter Obiechina

2,686
1
7
14

I think you have missed '>' operator in the first line. Could you add it ? – Aswin B Sep 18 '21 at 06:07
I hope it worked? – Peter Obiechina Sep 18 '21 at 06:08
Error: The argument type 'AsyncSnapshot>' can't be assigned to the parameter type 'AsyncSnapshot>>'. – Aswin B Sep 18 '21 at 06:12
.headerProfile(context, snapshot), ^ – Aswin B Sep 18 '21 at 06:12
This is the error I am getting in profile.dart file – Aswin B Sep 18 '21 at 06:13
And I have changed this line "Map map = snapshot.data.data();" into " Map? map = snapshot.data!.data(); " as it shows error there – Aswin B Sep 18 '21 at 06:14
The snapshot being passed to `headerProfile(context, snapshot)` should be defined with type `DocumentSnapshot>` – Peter Obiechina Sep 18 '21 at 06:16
Did this `Map? map = snapshot.data!.data();` resolve that problem? – Peter Obiechina Sep 18 '21 at 06:17
It resolved the problem arrises in that particular line, but the previous error '.headerProfile(context, snapshot)' is still there – Aswin B Sep 18 '21 at 06:19
Have you tried this "The snapshot being passed to `headerProfile(context, snapshot)` should be defined with type `DocumentSnapshot>`" – Peter Obiechina Sep 18 '21 at 06:20
Actually I couldn't pass it like that in that line. Are you asking me to do " Provider.of(context, listen: false) .headerProfile(context, DocumentSnapshot>)," like this right – Aswin B Sep 18 '21 at 06:22
Not really. `Provider.of(context, listen: false) .headerProfile(context, snapshot)` you will pass snapshot to this function. That snapshot should be of type `DocumentSnapshot>` – Peter Obiechina Sep 18 '21 at 06:25
Could you please check my streambuilder section in profile.dart file also,whether I have done it properly? – Aswin B Sep 18 '21 at 06:26
yes, you did okay. change `builder: (BuildContext context, AsyncSnapshot snapshot) {` to `builder: (BuildContext context, AsyncSnapshot>> snapshot) {` – Peter Obiechina Sep 18 '21 at 06:28
Yeah!!!! It worked!! – Aswin B Sep 18 '21 at 06:42
Niceeee. So glad I could help. – Peter Obiechina Sep 18 '21 at 06:43
You can upvote to make this answer easier to find for other users> – Peter Obiechina Sep 18 '21 at 06:43
Actually I am new to Stackoverflow so I couldn't upvote it due to reputations. Anyways Thanks a bunch!! – Aswin B Sep 18 '21 at 06:46
Okay, no problem. – Peter Obiechina Sep 18 '21 at 06:46

score 0 · Answer 2 · answered Sep 18 '21 at 05:35

0

can you please try like "snapshot.data['username']"??

also refer to this post link for fetching data from real time firebase DB

answered Sep 18 '21 at 05:35

Taqi Tahmid Tanzil

300
3
17

snapshot.data['username'], didn't work,as it showing 'The method '[]' can't be unconditionally invoked because the receiver can be 'null'. – Aswin B Sep 18 '21 at 06:09

Function can't be unconditionally invoked because it can be 'null'

2 Answers2