Error map

Non-nullable instance field must be initialized Dart: Non-nullable instance field 'name' must be initialized. Try adding an initializer expression, or a generative constructor that initializes it, or mark it 'late'

Flutter / Dart · layer 1, On your device

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Non-nullable instance field must be initialized — Dart: Non-nullable instance field 'name' must be initialized. Try adding an initializer expression, or a generative constructor that initializes it, or mark it 'late' (Flutter / Dart)Non-nullabl…LateInitializationError: Field has not been initialized — Dart: LateInitializationError: Field 'controller' has not been initialized (Flutter / Dart)LateInitializationE…The argument type can't be assigned to the parameter type — Dart: The argument type 'String?' can't be assigned to the parameter type 'String' (Flutter / Dart)The argument type c…Bad state: No element — Dart: Bad state: No element — .first, .last or .single on an empty list (Flutter / Dart)Bad state: No eleme…type 'Null' is not a subtype of type 'String' — Dart: type 'Null' is not a subtype of type 'String' in type cast (Flutter / Dart)type 'Null' is not …Error: Couldn't resolve the package — Dart: Error: Couldn't resolve the package 'x' in 'package:x/x.dart' (Flutter / Dart)Error: Couldn't res…The property/method can't be unconditionally accessed because the receiver can be null — Dart: The property 'length' can't be unconditionally accessed because the receiver can be 'null' (Flutter / Dart)The property/method…The named parameter is required, but there's no corresponding argument — Dart: The named parameter 'key' is required, but there's no corresponding argument (Flutter / Dart)The named parameter…setState() called after dispose() — Flutter: setState() called after dispose(): _MyState#1a2b3 (lifecycle state: defunct, not mounted) (Flutter / Dart)setState() called a…Null check operator used on a null value — Dart/Flutter: Null check operator used on a null value (Flutter / Dart)Null check operator…The getter/method isn't defined for the type — Dart: The getter 'name' isn't defined for the type 'User' / The method 'foo' isn't defined for the class (Flutter / Dart)The getter/method i…Cannot convert value of type — Swift: Cannot convert value of type 'X' to expected argument type 'Y' (iOS)Cannot convert valu…RangeError (index): Invalid value — Dart: RangeError (index): Invalid value: Valid value range is empty: 0 (Flutter / Dart)RangeError (index):…type '_InternalLinkedHashMap' is not a subtype of type 'List<dynamic>' — Dart: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'List<dynamic>' in type cast (Flutter / Dart)type '_InternalLink…FormatException: Unexpected character — Dart: FormatException: Unexpected character (at character 1) <!DOCTYPE html> — jsonDecode of an HTML page (Flutter / Dart)FormatException: Un…Bad state: Stream has already been listened to — Dart: Bad state: Stream has already been listened to (Flutter / Dart)Bad state: Stream h…Illegal argument in isolate message: object is unsendable — Dart: Invalid argument(s): Illegal argument in isolate message: object is unsendable - Library:'dart:async' Class: _Future@4048458 (Flutter / Dart)Illegal argument in…version solving failed (pub get) — Dart pub: Because app depends on intl ^0.19.0 and flutter_localizations from sdk depends on intl 0.18.1, version solving failed (Flutter / Dart)version solving fai…The current Dart SDK version is x; package requires SDK >= y — Dart pub: The current Dart SDK version is 2.19.0. Because app requires SDK version >=3.0.0 <4.0.0, version solving failed (Flutter / Dart)The current Dart SD…

Directly related (7)

LateInitializationError: Field has not been initializedFlutter / Dart

Dart: LateInitializationError: Field 'controller' has not been initialized

A `late` variable was read before it was assigned.

The argument type can't be assigned to the parameter typeFlutter / Dart

Dart: The argument type 'String?' can't be assigned to the parameter type 'String'

You passed a value whose type does not match what the function parameter requires.

Bad state: No elementFlutter / Dart

Dart: Bad state: No element — .first, .last or .single on an empty list

You called `.first`, `.last`, `.single` or `.reduce` on an empty collection.

type 'Null' is not a subtype of type 'String'Flutter / Dart

Dart: type 'Null' is not a subtype of type 'String' in type cast

A value that was `null` at runtime was cast or used as a non-nullable type, most often when parsing JSON.

Error: Couldn't resolve the packageFlutter / Dart

Dart: Error: Couldn't resolve the package 'x' in 'package:x/x.dart'

Code imports a package that is not in `pubspec.yaml` or `pub get` has not been run since adding it.

The property/method can't be unconditionally accessed because the receiver can be nullFlutter / Dart

Dart: The property 'length' can't be unconditionally accessed because the receiver can be 'null'

With null safety you used `.` on a nullable value; Dart requires a null check first.

The named parameter is required, but there's no corresponding argumentFlutter / Dart

Dart: The named parameter 'key' is required, but there's no corresponding argument

A constructor or function marked `required` for a parameter was called without it.

Two steps away (11)

setState() called after dispose()Flutter / Dart

Flutter: setState() called after dispose(): _MyState#1a2b3 (lifecycle state: defunct, not mounted)

An async callback (network, timer, stream) finished after the widget was removed and then called setState.

Null check operator used on a null valueFlutter / Dart

Dart/Flutter: Null check operator used on a null value

The ! operator was applied to a variable that was null at runtime.

The getter/method isn't defined for the typeFlutter / Dart

Dart: The getter 'name' isn't defined for the type 'User' / The method 'foo' isn't defined for the class

The analyzer cannot find that property or method on the object's static type.

Cannot convert value of typeiOS

Swift: Cannot convert value of type 'X' to expected argument type 'Y'

The value’s type doesn’t match what the function or property expects.

RangeError (index): Invalid valueFlutter / Dart

Dart: RangeError (index): Invalid value: Valid value range is empty: 0

A list or string was indexed outside its bounds, often an empty list or an off-by-one in `itemBuilder`.

type '_InternalLinkedHashMap' is not a subtype of type 'List<dynamic>'Flutter / Dart

Dart: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'List<dynamic>' in type cast

JSON decoded to a Map but your code expected a List (or the other way round).

FormatException: Unexpected characterFlutter / Dart

Dart: FormatException: Unexpected character (at character 1) <!DOCTYPE html> — jsonDecode of an HTML page

`jsonDecode` received something that is not JSON, commonly an HTML error page, an empty string, or a plain-text message.

Bad state: Stream has already been listened toFlutter / Dart

Dart: Bad state: Stream has already been listened to

A single-subscription stream was listened to twice, for instance by two `StreamBuilder`s or after a rebuild.

Illegal argument in isolate message: object is unsendableFlutter / Dart

Dart: Invalid argument(s): Illegal argument in isolate message: object is unsendable - Library:'dart:async' Class: _Future@4048458

You tried to send an object (closure, Future, socket, platform object) to another isolate that cannot be copied.

version solving failed (pub get)Flutter / Dart

Dart pub: Because app depends on intl ^0.19.0 and flutter_localizations from sdk depends on intl 0.18.1, version solving failed

`flutter pub get` cannot find a set of package versions that satisfy every dependency's constraints.

The current Dart SDK version is x; package requires SDK >= yFlutter / Dart

Dart pub: The current Dart SDK version is 2.19.0. Because app requires SDK version >=3.0.0 <4.0.0, version solving failed

A package (or your own pubspec) requires a newer Dart SDK than the one your Flutter installation provides.