Ch 7: runtime error in EventDetails.fromMap constructor about flutter-projects

[elstepherino]

It seems that in this statement:
var data = await db.collection('event_details').get();

data is now a QueryDocumentSnapshot...

[AnujPundir29]

It seems that the error originates here:

EventDetail.fromMap( dynamic obj ) {
this.id = obj['id']; // <<<< CRASH
this._description = obj['description'];
this._date = obj['date'];
this._startTime = obj['start_time'];
this._endTime = obj['end_time'];
this._speaker = obj['speaker'];
this._isFavorite = obj['is_favourite'];
}

Not sure why this is happening. Any ideas?

Thanks.

Here is the stack trace:

/flutter: [ERROR:flutter/lib/ui/ui_dart_state.cc(166)] Unhandled Exception: NoSuchMethodError: Class 'QueryDocumentSnapshot' has no instance method '[]'.
Receiver: Instance of 'QueryDocumentSnapshot'
Tried calling:
#0 Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
#1 new EventDetail.fromMap (package:events/models/event_detail.dart:14:18)
#2 _EventListState.getDetailsList. (package:events/screens/event_screen.dart:60:54)
#3 MappedListIterable.elementAt (dart:_internal/iterable.dart:417:31)
#4 ListIterator.moveNext (dart:_internal/iterable.dart:343:26)
#5 new List.from (dart:core-patch/array_patch.dart:38:29)
#6 new List.of (dart:core-patch/array_patch.dart:68:17)
#7 ListIterable.toList (dart:_internal/iterable.dart:211:44)
#8 _EventListState.getDetailsList (package:events/screens/event_screen.dart:60:66)

#9 _EventListState.initState (package:events/screens/event_screen.dart:31:7)
#10 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4684:58)
#11 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4520:5)
#12 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3490:14)
#13 Element.updateChild (package:flutter/src/widgets/framework.dart:3258:18)
#14 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4571:16)
#15 Element.rebuild (package:flutter/src/widgets/framework.dart:4262:5)
#16 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4525:5)
#17 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4520:5)
#18 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3490:14)
#19 Element.updateChild (package:flutter/src/widgets/framework.dart:3258:18)
#20 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4571:16)
#21 Element.rebuild (package:flutter/src/widgets/framework.dart:4262:5)
#22 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4525:5)
#23 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4520:5)
#24 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3490:14)
#25 Element.updateChild (package:flutter/src/widgets/framework.dart:3258:18)
#26 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4571:16)
#27 Element.rebuild (package:flutter/src/widgets/framework.dart:4262:5)
#28 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4525:5)
#29 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4520:5)
#30 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3490:14)
#31 MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5991:32)
#32 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3490:14)
#33 Element.updateChild (package:flutter/src/widgets/framework.dart:3258:18)
#34 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4571:16)
#35 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4719:11)
#36 Element.rebuild (package:flutter/src/widgets/framework.dart:4262:5)
#37 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4525:5)
#38 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4710:11)
#39 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4520:5)
#40 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3490:14)
#41 Element.updateChild (package:flutter/src/widgets/framework.dart:3258:18)
#42 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4571:16)
#43 Element.rebuild (package:flutter/src/widgets/framework.dart:4262:5)
#44 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4525:5)
#45 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4520:5)

Hey I am getting this error can you tell me what with code....

E/flutter (24002): [ERROR:flutter/lib/ui/ui_dart_state.cc(166)] Unhandled Exception: NoSuchMethodError: The method 'map' was called on null.
E/flutter (24002): Receiver: null
E/flutter (24002): Tried calling: map(Closure: (dynamic) => Movie)
�[38;5;244mE/flutter (24002): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5))�[39;49m
�[38;5;248mE/flutter (24002): #1 HttpHelper.getUpcoming�[39;49m
package:movies/http_helper.dart
E/flutter (24002):
�[38;5;248mE/flutter (24002): #2 _MovieListState.initialize�[39;49m
package:movies/movie_list.dart
�[38;5;248mE/flutter (24002): #3 _MovieListState.initState�[39;49m
package:movies/movie_list.dart
�[38;5;244mE/flutter (24002): #4 StatefulElement._firstBuild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #5 ComponentElement.mount�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #6 Element.inflateWidget�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #7 Element.updateChild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #8 ComponentElement.performRebuild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #9 Element.rebuild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #10 ComponentElement._firstBuild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #11 ComponentElement.mount�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #12 Element.inflateWidget�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #13 Element.updateChild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #14 SingleChildRenderObjectElement.mount�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #15 Element.inflateWidget�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #16 Element.updateChild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #17 ComponentElement.performRebuild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #18 Element.rebuild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #19 ComponentElement._firstBuild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #20 ComponentElement.mount�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #21 Element.inflateWidget�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #22 Element.updateChild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #23 SingleChildRenderObjectElement.mount�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #24 Element.inflateWidget�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #25 Element.updateChild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #26 SingleChildRenderObjectElement.mount�[39;49m
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�[38;5;244mE/flutter (24002): #27 Element.inflateWidget�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #28 Element.updateChild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #29 ComponentElement.performRebuild�[39;49m
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�[38;5;244mE/flutter (24002): #30 StatefulElement.performRebuild�[39;49m
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�[38;5;244mE/flutter (24002): #31 Element.rebuild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #32 ComponentElement._firstBuild�[39;49m
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�[38;5;244mE/flutter (24002): #33 StatefulElement._firstBuild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #34 ComponentElement.mount�[39;49m
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�[38;5;244mE/flutter (24002): #35 Element.inflateWidget�[39;49m
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�[38;5;244mE/flutter (24002): #36 Element.updateChild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #37 SingleChildRenderObjectElement.mount�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #38 Element.inflateWidget�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #39 Element.updateChild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #40 SingleChildRenderObjectElement.mount�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #41 Element.inflateWidget�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #42 Element.updateChild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #43 ComponentElement.performRebuild�[39;49m
package:flutter/…/widgets/framework.dart
�[38;5;244mE/flutter (24002): #44 StatefulElement.performRebuild�[39;49m
package:flutter/…/widgets/framework.dart
E/flutter (24002): #45 Element.rebuild (package:f
I/Choreographer(24002): Skipped 1 frames! The application may be doing too much work on its main thread.
Application finished.
Exited (sigterm)