Issue I’m learning flutter from the older version with the new one. so, I have many times problem with null safety. I have code in database.dart file like this : import ‘package:cloud_firestore/cloud_firestore.dart’; class DatabaseService { final String uid; DatabaseService({required this.uid});
Continue readingTag: null-safety
How best to convert old Dart code that triggers "The non-nullable variable must be assigned" error?
Issue Take the following non-null safe Dart code: static String appBarShiftTitleString(int fromEpochSeconds) { String monthWord; String dayWord; DateTime dt = DateTime.fromMillisecondsSinceEpoch(fromEpochSeconds * 1000); switch (dt.month) { case 1: monthWord = "Jan"; break; case 2: monthWord = "Feb"; break; case 3:
Continue readingHow best to convert old Dart code that triggers "parameter can't be 'null' but the implicit default value is 'null'." error?
Issue Take the following non-null safe Dart code: class RoundedButton extends StatelessWidget { RoundedButton({this.title, this.color, @required this.onPressed}); final Color color; final String title; final Function onPressed; @override Widget build(BuildContext context) { return Padding( padding: EdgeInsets.symmetric(vertical: 16.0), child: Material( elevation: 5.0,
Continue readingMethod 'showBottomSheet' cannot be called on 'ScaffoldState?' because it is potentially null
Issue Hello I’m getting this error when I tried to run the code lib/layout/home_layout.dart:54:36: Error: Method ‘showBottomSheet’ cannot be called on ‘ScaffoldState?’ because it is potentially null. – ‘ScaffoldState’ is from ‘package:flutter/src/material/scaffold.dart’ (‘/C:/src/flutter/packages/flutter/lib/src/material/scaffold.dart’). Try calling using ?. instead. scaffoldKey.currentState.showBottomSheet( ^^^^^^^^^^^^^^^
Continue readingI have a problem with Null Safety an the problem is 'Null check operator used on a null value'
Issue It happened when getting some data from firebase and decoding them using model, and here is the method: UserModel? userModel; void getUser() { emit(GetUserLoadingsState()); FirebaseFirestore.instance.collection(‘users’).doc(uId).get().then((value) { userModel = UserModel.fromJson(value.data()!); emit(GetUserSuccessState()); }).catchError((error) { emit(GetUserErrorState(error.toString())); }); } Calling the method return
Continue readingA value of type 'StreamSink<dynamic>' can't be returned from the function 'assessmentSink'
Issue class AssessmentBloc { late AssessmentRepository _genRepository; late StreamController assessmentController; late StreamController submitAssessmentController; StreamSink<ApiResponse<AssessmentModel>> get assessmentSink => assessmentController.sink; StreamSink<ApiResponse<AssessmentResult>> get submitSink => submitAssessmentController.sink; AssessmentBloc() { assessmentController = StreamController<ApiResponse<AssessmentModel>>(); submitAssessmentController = StreamController<ApiResponse<AssessmentResult>>(); _genRepository = AssessmentRepository(); } dispose() { assessmentController?.close(); submitAssessmentController?.close(); }
Continue reading"The argument type 'String?' can't be assigned to the parameter type 'String'" when using stdin.readLineSync()
Issue i’m new at dart. I don’t know what kind of mistake i have made, but this code didn’t work. Is a simple code, just read the age in terminal and say it’s underage or over 18. import ‘dart:io’; main(){
Continue readingWhy im getting this error Warning: Operand of null-aware operation '??' has type 'String' which excludes null. Dart Language
Issue so i was learning about SWITCH and CASE Statements in dart language, in the course he explains the code but he don’t get an error while i get one. the error i get : Warning: Operand of null-aware operation
Continue readingWhat is your recommended workflow for Flutter null safety migration tool
Issue I am using the Flutter null safety migration tool. What is your recommended workflow for null safety migration? For example: Start at main.dart first and work your way out from there? Start with models or classes first? Start with
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