I can't stream (read) Documents that contain array properties that are Maps in Firestore.
Using Firestore with a document containing an array with a simple String type works as expected. Easy to write (append with FieldValue.arrayUnion(['data1','data2','data3']) and stream back out with code like:
var test2 = List<String>();
for (var item in data['items']) {
print('The item $item');
test2.add(item);
}
test2 can now be used as my items property.
When I try and use a List where item type becomes a Map in Firestore and is just a simple Class containing a few Strings and a date property. I can write these to FireStore but I can't read them back out.
The following code fails: (no errors in the Debug Console but it doesn't run)
var test2 = List<Item>();
data['items'].forEach((item) {
var description = item['description'];
print('The description $description'); // <-- I don't get past this
final x = Item.fromMap(item); // <-- so I can't even attempt this
return test2.add(x);
});
I never get to actually call my Item.fromMap constructor: here is another try:
// fails
final theItems = data['items'].map((x) {
return Item.fromMap(x); // <-- never get here
});
Although the DEBUG CONSOLE doesn't say there is any problem. If I inspect theItems variable (the debugger 'jumps' a couple of lines down to my return) after the failed iteration it looks like this:
MappedListIterable
_f:Closure
_source:List (1 item)
first:Unhandled exception:\ntype '_InternalLinkedHashMap<dynamic, dynamic>' is not a subtype of type 'Map<String, dynamic>'\n#0 new Listing.fromMap.<anonymous closure> isEmpty:false
isNotEmpty:true
iterator:ListIterator
last:Unhandled exception:\ntype '_InternalLinkedHashMap<dynamic, dynamic>' is not a subtype of
So bad things have happened but I have no idea why!
Has anyone actually written and retrieved Firestore array properties that contain Maps?
Any help in how to proceed would be greatly appreciated!
More: screen shot of the document
Here is the code that reads (streams) the collection
Stream<List<T>> collectionStream<T>({
#required String path,
#required T builder(Map<String, dynamic> data, String documentID),
#required String userId,
Query queryBuilder(Query query),
int sort(T lhs, T rhs),
}) {
Query query = Firestore.instance.collection(path);
if (queryBuilder != null) {
query = queryBuilder(query);
}
final Stream<QuerySnapshot> snapshots = query.snapshots();
return snapshots.map((snapshot) {
//print('document: path $path ${snapshot.documents[0]?.documentID}');
final result = snapshot.documents
.map((snapshot) => builder(snapshot.data, snapshot.documentID))
.where((value) => value != null)
.toList();
if (sort != null) {
result.sort(sort);
}
print('returning from CollectionStream');
return result;
});
}
the .map is where the problem comes in. The builder function resolves to this:
builder: (data, documentId) {
return Listing.fromMap(data, documentId);
},
Which ends up here
factory Listing.fromMap(
Map<String, dynamic> data,
String documentId,
) {
if (data == null) {
return null;
}
final theTime = (data['createdAt'] as Timestamp).toDate();
// see above code where I fail at getting at the items property/field
Here is the Item Class:
class Item {
Item(this.description, this.imageURL, this.thumbnailURL,
{this.status = ItemStatus.active,
this.type = ListingType.free,
this.price = 0,
this.isUpdate = false,
this.createdAt});
final String description;
final String imageURL;
final String thumbnailURL;
final ItemStatus status;
final ListingType type;
final int price;
final bool isUpdate;
DateTime createdAt;
factory Item.fromMap(
Map<String, dynamic> data,
) {
if (data == null) {
return null;
}
final theTime = (data['createdAt'] as Timestamp).toDate();
return Item(
data['description'],
data['imageURL'],
data['thumbnailURL'],
status: _itemStatusFromString(data['status']),
type: data['type'] == 'free' ? ListingType.free : ListingType.flatRate,
createdAt: theTime,
);
}
Map<String, dynamic> toMap() {
// enums are for shit in Dart
final statusString = status.toString().split('.')[1];
final typeString = type.toString().split('.')[1];
return {
'description': description,
'imageURL': imageURL,
'thumbnailURL': thumbnailURL,
'itemStatus': statusString,
'price': price,
'listingType': typeString,
if (!isUpdate) 'createdAt': DateTime.now(),
if (isUpdate) 'updatedAt': DateTime.now(),
};
}
}
The above is never called to read (we crash) ... it is called to write the data.
This is a known issue with Firestore. Here is the starting thread Flutter issues I found
From reading through the issues it seems lots of folks use a serializer package which is where the issue surfaced. Its still active...
Here is my solution NOT using a serializer and just doing it 'by hand'.
I was able simplify the problem and generate an error that was Google-able. Below is a single page which just writes and reads a single Document. The Class A and B are as small as can be.
So the code writes a single document to Firestore the contains two properties. A name and items. The items being the List of Class B that Class A contains. Checkout the Firebase console. The reading just does that.
No StreamController just the Console. The problem is in the fromMap method where we have to convert the array of objects in Firesote to a List of class instances in Dart. This should not be this difficult and at a minimum it should be documented ....
the line
var theRealItems = data['items'].map((i) => B.fromMap(i));
will generate the error. And needs to be replaced with
var theItems = data['items'].map((i) {
var z = Map<String, dynamic>.from(i);
print(z['description']);
return B.fromMap(z);
}).toList();
var theRealItems = List<B>.from(theItems);
Why this is so difficult is still a mystery to me! Anyone improving this code: I'm all ears.
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
class A {
A(this.name, this.items);
final name;
final List<B> items;
factory A.fromMap(
Map<String, dynamic> data,
String documentId,
) {
if (data == null) {
return null;
}
// we crash here !!!
var theRealItems = data['items'].map((i) => B.fromMap(i));
// uncomment the 6 lines below
// var theItems = data['items'].map((i) {
// var z = Map<String, dynamic>.from(i);
// print(z['description']);
// return B.fromMap(z);
// }).toList();
// var theRealItems = List<B>.from(theItems);
return A(data['name'], theRealItems);
}
Map<String, dynamic> toMap() {
var theItems = items.map((i) => i.toMap()).toList();
return {'name': name, 'items': theItems};
}
}
class B {
B(this.description);
final description;
factory B.fromMap(
Map<String, dynamic> data,
) {
if (data == null) {
return null;
}
return B(data['description']);
}
Map<String, dynamic> toMap() {
return {
'description': description,
};
}
}
class Test extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Container(
child: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
RaisedButton(
onPressed: () => _write(),
child: Text('Write the Doc'),
),
RaisedButton(
onPressed: () => _read(),
child: Text('Read the Doc ... check Debug Console!'),
),
],
),
),
);
}
_write() async {
try {
var b = B('Inside B!');
List<B> theList = List<B>();
theList.add(b);
var a = A('myName', theList);
await Firestore.instance
.collection('test')
.document('testDoc')
.setData(a.toMap());
print('returning from write!');
} catch (e) {
print('Error ${e.toString()}');
}
}
_read() async {
try {
var aFromFs = await Firestore.instance
.collection('test')
.document('testDoc')
.get();
var a = A.fromMap(aFromFs.data, aFromFs.documentID);
print('the A from FireBase $a with name ${a.name} first item ${a.items.first.description}');
print('returning from read!');
} catch (e) {
print('Oh no Error! ${e.toString()}');
}
}
}
In the below code Name refers to the name of your respective document and collection.
Let's say you want to get "imageURL" and "thumbnailUrl" for now and update the values without deleting or changing other fields inside the array.
String imageUrl ;
String thumbnailUrl;
DocumentReference _docReference = FirebaseFirestore.instance.collection(NAME).doc(NAME);
//refering to the specific document
Map<String, dynamic> neededData= allDocsFromTraining.data();
//getting all the keys and values inside the document
List<Map<String, dynamic>> _yourDocument=
(neededData["items"] as List<dynamic>)
.map((m) => Map<String, dynamic>.from(m))
.toList();
//only getting the list of items
for (int index = 0; index < _yourDocument.length; index++) {
Map<String, dynamic> _getMap = _yourDocument[index];
if (_getMap["price"] == 0)
//giving a condition to get the desired value and make changes
{
//setting the variables with the value from the database
setState(() {
imageUrl = _getMap["imageURL"];
thumbnailUrl = _getMap["thumbnailURL"]
});
///Use this if you want to update value of imageURL and thumbnailURL at that specific index of an array
_getMap['imageURL'] = "Your Updated URL";
_getMap['thumbnailURL'] = "Your Updated Url;
break;
} else {}
}
await _docReference.update({"items": _yourDocument});
//this adds the updated value to your database.
Related
I'm trying to get afield value into a list of string from documents in the firebase that match the WHERE of a field value from a value of my own.
(I wanna show images above each other to create a full picture depending on the data, using two fields to be exact and then creating a list of images to show as positioned inside a Stack)
my code:
Implant Class:
class Implant {
final String id;
final String pid;
final String aptid;
late String type;
late double? sizew;
late int? sizel;
late String? positionQ;
late int? positionN;
Implant(this.id, this.pid, this.aptid, this.type, this.sizew, this.sizel,
this.positionQ, this.positionN);
Map<String, dynamic> toJson() => {
'ID': id,
'PID': pid,
'APTID': aptid,
'TYPE': type,
'SIZEW': sizew,
'SIZEL': sizel,
'POSITIONQ': positionQ,
'POSITIONN': positionN,
};
factory Implant.fromJson(Map<String, dynamic> json) {
return Implant(
json['ID'],
json['PID'],
json['APTID'],
json['TYPE'],
json['SIZEW'],
json['SIZEL'],
json['POSITIONQ'],
json['POSITIONN'],
);
}
static Map<String, dynamic> toMap(Implant implant) => {
'ID': implant.id,
'PID': implant.pid,
'APTID': implant.aptid,
'TYPE': implant.type,
'SIZEW': implant.sizew,
'SIZEL': implant.sizel,
'POSITIONQ': implant.positionQ,
'POSITIONN': implant.positionN,
};
static String encode(List<Implant> implant) => json.encode(
implant
.map<Map<String, dynamic>>((implant) => Implant.toMap(implant))
.toList(),
);
static List<Implant> decode(String implants) =>
(json.decode(implants) as List<dynamic>)
.map<Implant>((implant) => Implant.fromJson(implant))
.toList();
}
Future of list of string function:
static Future<List<String>> getImplants(Patient patient) async {
List<String> result = ['assets/images/teeth/empty.png'];
var collection = FirebaseFirestore.instance.collection('implants');
var docSnapshot = await collection.doc(patient.id).get();
if (docSnapshot.exists) {
Map<String, dynamic> data = docSnapshot.data()!;
result.add(data['POSITIONQ'] + data['POSITIONN']);
}
return result;
}
How I translate them into Stack and Positioned:
static Future<void> showPatientImplants(BuildContext context, Patient patient,
{bool spaces = true}) async {
List<String> myImplants;
myImplants = await getImplants(patient);
List<Widget> x = [Image.asset('assets/images/teeth/empty.png')];
myImplants.forEach((element) {
x.add(Image.asset(element));
});
return await showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
scrollable: true,
content: SingleChildScrollView(
child: GestureDetector(
onTap: () {
log(myImplants.toString());
},
child: Stack(
children: x,
),
),
),
);
});
}
The only problem I'm facing -I think- is that the Future<List> function doesn't get me the values I need.
I tried using other functions I found on SO and google, nothing worked.
I guess I can try using the stream and Listview.builder just to get the files names but it seems like exactly how it shouldn't be done.
any help is appreciated.
Never mind Solved it using the following code:
static Future<List<String>> getImplants(Patient patient) async {
List<String> result = ['assets/images/teeth/empty.png'];
log('ID:${patient.id}');
var collection = FirebaseFirestore.instance
.collection('implants')
.where('PID', isEqualTo: patient.id);
var docSnapshot = await collection.get();
for (var element in docSnapshot.docs) {
if (element.exists) {
Map<String, dynamic> data = element.data();
result.add(data['POSITIONQ'].toString() + data['POSITIONN'].toString());
}
}
return result;
}
but if anyone has a better idea I appreciate it along with everyone who has a similar problem.
I would like to return the first five value of name from the JSON response above
Future <List<UserModel>> fetchData() async {
final response =
await http.get(Uri.parse(URLCONST.API_URL));
if (response.statusCode == 200) {
List jsonResponse = json.decode(response.body);
return jsonResponse.map((user) => new UserModel.fromJson(user)).toList();
} else {
throw Exception('Unexpected error occured!');
}
}
Here's the model below.
class UserModel {
int id;
String name;
UserModel({
required this.id,
required this.name,
});
factory UserModel.fromJson(Map<String, dynamic> json) {
return UserModel(
id: json['id'],
name: json['name'],
);
}
}
API has several values in the list and I'd like to return the first 5 only
if i understood correctly, you can do something like this:
jsonResponse.map((user) => new UserModel
.fromJson(user))
// this will take only the first five elements of the iterable
.take(5)
// this will map each user to its corresponding name
.map((user) => user.name)
// this, as you already know, will convert the iterable to a list
.toList();
this will return a List<String> containing the first five names
There are two Functions that I use to convert two String variables into JSON and from JSON.
String toJson() {
Map<String,dynamic> map = {'name': name,'count':checkListCount,'description':description,};
return jsonEncode(map)
}
fromJson(String context){
Map<String,dynamic> map = jsonDecode(contents)
name = map['name'];
description = map['description'];
return '0';
}
How i can use this to functions to covert List?
There is my list
List<CheckListPoint> checkListPoints = [];
CheckListPoint{
bool correctly = false;
bool passed = false;
String requirement = '';
}
variables that I have in CheckListPoint will change by the user later in the app.
i am not exactly getting which key will give you the list of data from your question,
but suppose you have a response in with "data" key is giving you list of items,
then you can add from JSON with ->
data : List<User>.from(json["data"].map((x) => User.fromJson(x))),
and to convert it to JSON you need
"data": List<dynamic>.from(data.map((x) => x.toJson())),
i hope this is what you are asking for
I did a very similiar thing when fetching messages from firebase. It's the same as parsing from JSON since both values are dynamic.
Here I convert a DataSnapshot to a List
Future<List<Message>> getMessages(DataSnapshot snapshot) async {
List<Message> msgs = List.empty(growable: true);
if(snapshot.value != null) {
Map<dynamic, dynamic> messages = snapshot.value;
messages.forEach((key, value) {
msgs.add(Message.fromFirebase(value));
});
}
return msgs;
}
And here is the Message class:
class Message {
String message;
String senderId;
int time;
Message.fromFirebase(Map<dynamic, dynamic> json) :
message = json["message"],
senderId = json["senderId"],
time = json["time"];
}
I am implementing login with provider but I am not getting data on dashboard page.
Model Class
class LoginModel {
Data data;
int status;
String message;
LoginModel({this.data, this.status, this.message});
LoginModel.fromJson(Map<String, dynamic> json) {
data = json['data'] != null ? new Data.fromJson(json['data']) : null;
status = json['status'];
message = json['message'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
if (this.data != null) {
data['data'] = this.data.toJson();
}
data['status'] = this.status;
data['message'] = this.message;
return data;
}
}
class Data {
String customerId;
String customerMobileNo;
String customerToken;
String otp;
Data({this.customerId, this.customerMobileNo, this.customerToken, this.otp});
Data.fromJson(Map<String, dynamic> json) {
customerId = json['customerId'];
customerMobileNo = json['customerMobileNo'];
customerToken = json['customerToken'];
otp = json['otp'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['customerId'] = this.customerId;
data['customerMobileNo'] = this.customerMobileNo;
data['customerToken'] = this.customerToken;
data['otp'] = this.otp;
return data;
}
}
Provider Class
class AuthProvider extends ChangeNotifier {
Future<LoginModel> generateOTP(String mobileNumber) async {
var result;
Response response = await post(
AppUrl.login,
body: {
'mobileNo': mobileNumber,
},
);
if(response.statusCode==200) {
final responseData = json.decode(response.body);
var userData = responseData['data'];
print(responseData);
LoginModel authUser = LoginModel.fromJson(userData);
notifyListeners();
}
else {
print("Something went wrong");
}
return result;
}
}
Display Page
class Dashboard extends StatelessWidget {
#override
Widget build(BuildContext context) {
final userTest = Provider.of<AuthProvider>(context);
return Scaffold(
body: Center(
child: ListView(
shrinkWrap: true,
children: [
Text(userTest.authUser.data.customerToken),
],
),
),
);
}
Error
The following NoSuchMethodError was thrown while handling a gesture:
The getter 'customerToken' was called on null.
Receiver: null
Tried calling: customerToken
How can I access the property of LoginModel class. Can anyone solve my query please help me, I tried a lott but I can not get value.
You cannot notify your listeners with normal Future functions (though, I am not sure because you didn't provide the full code of your provider class). You will have to put your generateOTP() function in a changenotifier class that will help you to notify your listeners whenever required and make it scoped to your widget.
You are getting this error because you are not storing your token anywhere or you are not invoking your storage token before using it. So first, please try to store your token and invoke it before using it.
LoginModel authUser = LoginModel.fromJson(userData); you are initializing value to method variable LoginModel authUser not a class variable authUser try removing LoginModel from before 'authUser'.
In Dashboard you should also check for null value, you can do that like this userTest?.authUser?.data?.customerToken ?? ''
I want to convert a list of 'Box' objects to a json file and also read it back in (json file to a list a 'Box' objects), but I'm a bit stuck on the implementation. I have written the below code, but I can only write a single 'Box' object to the json and convert a single 'Box' object back. When I try to do this with a list I hit errors like data that gets overwritten or just a single object that gets returned.
So in short, I want to write a List to json and convert json to List
I have the following data structure
Box model
class Box {
final String nameBox;
final List<Item> items;
Box({#required this.nameBox, #required this.items});
factory Box.fromJson(Map<String, dynamic> json) {
var items = json['items'];
List<Item> itemsList = items.cast<Item>();
return new Box(
nameBox: json["nameBox"],
items: itemsList
);
}
Map<String, dynamic> toJson() => {
"nameBox": nameBox,
"items": items,
};
}
Box fromJson(String boxData) {
return Box.fromJson(json.decode(boxData));
}
String toJson(Box box) {
return json.encode(box.toJson());
}
Item model
class Item {
final String itemName;
final int quantity;
Item({#required this.itemName, #required this.quantity});
factory Item.fromJson(Map<String, dynamic> json) {
return new Item(itemName: json["itemName"], quantity: json["quantity"]);
}
Map<String, dynamic> toJson() => {
"itemName": itemName,
"quantity": quantity,
};
}
Item fromJson(String itemData) {
return Item.fromJson(json.decode(itemData));
}
String toJson(Item item) {
return json.encode(item.toJson());
}
writeToJson function
Future writeJson(Box box) async {
final file = await _localFile;
List<Box> tempRead = await returnBoxes();
if (tempRead.isEmpty || tempRead == null) {
return;
}
tempRead.add(box);
file.writeAsString(json.encode(tempRead));
}
readJson function
Future<List<Box>> returnBoxes() async {
final file = await _localFile;
List<Box> boxList = new List<Box>();
Map<String, dynamic> content = await json.decode(file.readAsStringSync());
boxList.add(Box.fromJson(content));
return boxList;
}
I also tried to cast the json content to a list, but then I hit some iterable errors. Any who can help me out?
JSON has this idiosyncrasy that everything is either an object or an array, and you don't know what you get until you decode it. Dart decodes the two json types into a Map<String, dynamic> and List<dynamic> respectively. (The reason that you get dynamic is because each of them could itself then be a value, a json array or a json object, recursively.)
Dart encodes a Dart object by calling toJson on it and a Dart list by emitting a [ then each member of the list then a ].
Knowing that, it's easy to encode and decode arrays/lists. (I removed all the unnecessary code.)
class Box {
final String nameBox;
final List<Item> items;
Box({#required this.nameBox, #required this.items});
factory Box.fromJson(Map<String, dynamic> json) => Box(
nameBox: json['nameBox'],
items: json['items'].map<Item>((e) => Item.fromJson(e)).toList(),
);
Map<String, dynamic> toJson() => {
'nameBox': nameBox,
'items': items,
};
}
class Item {
final String itemName;
final int quantity;
Item({#required this.itemName, #required this.quantity});
factory Item.fromJson(Map<String, dynamic> json) => Item(
itemName: json['itemName'],
quantity: json['quantity'],
);
Map<String, dynamic> toJson() => {
'itemName': itemName,
'quantity': quantity,
};
}
Future writeJson(Box box) async {
final file = await _localFile;
var boxes = await returnBoxes();
/* I think you probably don't want this...
if (boxes.isEmpty || boxes == null) {
return;
}*/
// but rather, this
if (boxes == null) boxes = [];
boxes.add(box);
await file.writeAsString(json.encode(boxes));
}
Future<List<Box>> returnBoxes() async {
final file = await _localFile;
// because the json is an array (i.e. enclosed in []) it will be decoded
// as a Dart List<dynamic>
List<dynamic> d = json.decode(await file.readAsString());
// here we map the List<dynamic> to a series of Box elements
// each dynamic is passed to the Box.fromJson constructor
// and the series is formed into a List by toList
return d.map<Box>((e) => Box.fromJson(e)).toList();
}