CODEWITHSUNDEEP
dartfluttergoogle-cloud-firestore
Mayur Prajapati
Mayur Prajapati

Reputation: 627

Unhandled Exception: NoSuchMethodError: The method 'toDate' was called on null

I'm developing a chatting application using Firebase.

for some time i'm getting this error Unhandled Exception: NoSuchMethodError: The method 'toDate' was called on null.

Getting error when converting Timestamp to DateTime using toDate().

GIVES ERROR FOR SOME TIME AND THEN ERROR DISAPPEARS.

PLEASE CONSIDER THIS GIF.

THIS

HERE IS FIRESTORE DATATYPE AS TimeStamp.

enter image description here

SOURCE CODE

class ChatMessageModel {
  bool isSentByMe;
  String msg = '';

  ///SERVER TIME
  Timestamp time;
  DateTime localTime;
  String timeStamp;
  String fromUid;
  String toUid;

  ChatMessageModel._();

  ChatMessageModel.fromSnapshot(DocumentSnapshot snapshot) {
    this.isSentByMe =
        snapshot.data['from'] == LoginBloc.instance.firebaseUser.uid;
    this.msg = snapshot.data['msg'];
    this.timeStamp = snapshot.data['time'].toString();
    this.time = snapshot.data['time'];
    this.fromUid = snapshot.data['from'];
    this.toUid = snapshot.data['to'];
    this.localTime = this.time.toDate(); //ERROR
  }
}

THANKS IN ADVANCE.

Upvotes: 6

Views: 4010

Answers (4)

josef
josef

Reputation: 193

This code worked for me:

ds['time'] == null? Text(DateTime.now().toString())
  : Text(
   DateFormat("hh:mm a").format(
   ds['time'].toDate(),
 ),
),

Upvotes: 0

Shubham Prajapati
Shubham Prajapati

Reputation: 71

It is showing error because at the calling time of this.time, this.time getting null. So toDate() function can't be able to applying on null

Try changing : this.localTime = this.time.toDate();

To :

this.localTime = this.time == null ? DateTime.now()
    : this.time.toDate();

OR You can use like this :

String stringtime = widget.time == null
        ? DateTime.now().toString()
        : widget.time.toDate().toString();
    // stringtime = widget.time.toDate().toString();
    DateTime date = DateTime.parse(stringtime);
    String clocktime = DateFormat('hh:mm a').format(date);

Hope it helps, worked for me :)

Upvotes: 4

user14344186
user14344186

Reputation: 1

try changing

this.localTime = this.time.toDate();

to

this.localTime = this.time.toDate()==null?DateTime().now():this.time.toDate();

for better readability save this.time.toDate() in a variable.Hope it helps,worked for me

Upvotes: 0

Mazin Ibrahim
Mazin Ibrahim

Reputation: 7889

Your code is trying to convert time to Date before it is fetched, a short workaround would be initializing your time variable with current time before server's value loads:

  Timestamp time = new Timestamp( new Date(2019,3,4) );

another solution would be to use an async method to await the value from the server before converting it, which you can't afford given that you want to use it in instant messeging.More can be found in the official Firebase documentation and the android developer documentation.

Note that the above code will result in a Timestamp pointing to midnight, but shouldn't be an issue since it is a brief placeholder compared to Firebase response speed.

Upvotes: 2

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