In Javascript I would use a spread operator:
Now I have the same problem with Flutter:
Widget build(BuildContext context) {
return Column(
children: <Widget>[
MyHeader(),
_buildListOfWidgetForBody(), // <- how to spread this <Widget>[] ????
MyCustomFooter(),
],
);
}
You can now do spreading from Dart 2.3
var a = [0,1,2,3,4];
var b = [6,7,8,9];
var c = [...a,5,...b];
print(c); // prints: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
There is an issue to add this to future version of dart https://github.com/dart-lang/language/issues/47
but for now you can use sync* and yield*
Iterable<Widget> _buildChildren sync* {
yield MyHeader();
yield* _buildListOfWidgetForBody();
yield MyCustomFooter();
}
EDIT: As of Dart 2.3 you can now do:
Widget build(BuildContext context) {
return Column(
children: <Widget>[
MyHeader(),
..._buildListOfWidgetForBody(),
MyCustomFooter(),
],
);
}
Update - 20th April 2019
You can now use the spread operator since Dart 2.3 was released.
List<int> a = [0,1,2,3,4];
List<int> b = [6,7,8,9];
List<int> c = [...a,5,...b];
FireStore use another field in model
authInstance
.collection('fav_product')
.add(
{
...product.toMap(),
'field':'value',
}
);
Related
So I have created a BLOC structure with a Stream as given below. The Fetcher would receive changes to a list of Chatroom ids. Then using the transformer, it would add the data in the stream to a Cache map and pipe it to the output.
Now the catch here is that each Chatroom IDs will be used to create a stream instance, so subscribe to any changes in the Chatroom data. So the Cache map basically has the Chatroom ID mapped to its corresponding Stream. ChatRoomProvider is binds the bloc with the app.
class ChatRoomBloc {
// this is similar to the Streambuilder and Itemsbuilder we have in the Stories bloc
final _chatroomsFetcher = PublishSubject<String>();
final _chatroomsOutput =
BehaviorSubject<Map<String, Observable<ChatroomModel>>>();
// Getter to Stream
Observable<Map<String, Observable<ChatroomModel>>> get chatroomStream =>
_chatroomsOutput.stream;
ChatRoomBloc() {
chatRoomPath.listen((chatrooms) => chatrooms.documents
.forEach((f) => _chatroomsFetcher.sink.add(f.documentID)));
_chatroomsFetcher.stream
.transform(_chatroomsTransformer())
.pipe(_chatroomsOutput);
}
ScanStreamTransformer<String, Map<String, Observable<ChatroomModel>>>
_chatroomsTransformer() {
return ScanStreamTransformer(
(Map<String, Observable<ChatroomModel>> cache, String id, index) {
// adding the iteam to cache map
cache[id] = chatRoomInfo(id);
print('cache ${cache.toString()}');
return cache;
}, <String, Observable<ChatroomModel>>{});
}
dispose() {
_chatroomsFetcher.close();
_chatroomsOutput.close();
}
}
Observable<ChatroomModel> chatRoomInfo(String _chatrooms) {
final _chatroomInfo = PublishSubject<ChatroomModel>();
Firestore.instance
.collection('chatRooms')
.document(_chatrooms)
.snapshots()
.listen((chatroomInfo) =>
_chatroomInfo.sink.add(ChatroomModel.fromJson(chatroomInfo.data)));
dispose() {
_chatroomInfo.close();
}
return _chatroomInfo.stream;
}
Then I create a Streambuilder with a List view to list the IDs and any data from their corresponding streams as given below.
class FeedList extends StatelessWidget {
#override
Widget build(BuildContext context) {
final chatroomBloc = ChatRoomProvider.of(context);
return Scaffold(
appBar: AppBar(
title: Text('Chat Room'),
),
body: buildList(chatroomBloc),
);
}
Widget buildList(ChatRoomBloc chatroomBloc) {
return StreamBuilder(
// Stream only top ids to display
stream: chatroomBloc.chatroomStream,
builder: (context,
AsyncSnapshot<Map<String, Observable<ChatroomModel>>> snapshot) {
if (!snapshot.hasData) { // no data yet
return Center(child: CircularProgressIndicator());
}
return ListView.builder(
itemCount: snapshot.data.length,
itemBuilder: (context, int index) {
print('index $index and ${snapshot.data}');
return buildTile(snapshot.data[index]);
},
);
});
}
Widget buildTile(Observable<ChatroomModel> chatroomInfoStream) {
return StreamBuilder(
stream: chatroomInfoStream,
builder: (context, AsyncSnapshot<ChatroomModel> chatroomSnapshot) {
if (!chatroomSnapshot.hasData) {
return Center(
child: CircularProgressIndicator(),
);
}
print('${chatroomSnapshot.data.name}');
print('${chatroomSnapshot.data.members.toString()}');
return Column(children: [
ListTile(
title: Text('${chatroomSnapshot.data.name}'),
trailing: Column(
children: <Widget>[
Icon(Icons.comment),
],
),
),
Divider(
height: 8.0,
),
]);
});
}
}
The output I am getting is given below. The Streambuilder is stuck at CircularProgressIndicator in the buildTile method. I think it means that the instances are getting created and added in the cache map, but they are lot listening to the right instances or there is something wrong in the way I wired up the streams. Can you please help ?
I/flutter (12856): cache {H8j0EHhu2QpicgFDGXYZ: Instance of 'PublishSubject<ChatroomModel>'}
I/flutter (12856): cache {H8j0EHhu2QpicgFDGXYZ: Instance of 'PublishSubject<ChatroomModel>', QAhKYk1cfoq8N8O6WY2N: Instance of 'PublishSubject<ChatroomModel>'}
I/flutter (12856): index 0 and {H8j0EHhu2QpicgFDGXYZ: Instance of 'PublishSubject<ChatroomModel>', QAhKYk1cfoq8N8O6WY2N: Instance of 'PublishSubject<ChatroomModel>'}
I/flutter (12856): index 1 and {H8j0EHhu2QpicgFDGXYZ: Instance of 'PublishSubject<ChatroomModel>', QAhKYk1cfoq8N8O6WY2N: Instance of 'PublishSubject<ChatroomModel>'}
As a quick fix, maybe try:
final _chatroomInfo = BehaviorSubject<ChatroomModel>();
On a second note:
The code in its current state is hard to read and understand, it's unmaintainable and inefficient. I'm not sure what you are actually trying to do.
It's a bad idea to nest StreamBuilders. It will delay the display of the chat list by at least 2 frames, because every StreamBuilder renders at least one empty frame (data = null).
Listening to a stream and feeding the result into a Subject will also add delays.
If possible, try to remove all subjects. Instead, use rx operators.
The BLoC should provide a single output stream that provides all the data that is required to render the chat list.
I am writing a code in flutter in which I am using an SQFlite database. I want to insert image widget from the assets, and I am getting the name of the image from database.
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text("Single Line diagram"),backgroundColor: Colors.red.shade700,),
body: SingleChildScrollView(
scrollDirection: Axis.horizontal,
child: Align(
//alignment: Alignment.center,
child: SingleChildScrollView(
scrollDirection: Axis.vertical,
child: Row(
//crossAxisAlignment: CrossAxisAlignment.center,
children: imageList(),
),
),
)
),
);
}
The above code calls imageList() for the list of images to display.
List<Widget> imageList(){
List<Widget> singleLineImages = new List();
List unit;
for (int i = 0; i <= widget.unitsList.length-1; i++){
for (int j = 1; j <= int.parse(widget.unitsList[i].quantity); j++){
print("${widget.unitsList[i].bulletin}, ${widget.unitsList[i].mountType}, ${widget.unitsList[i].disconnect}");
getfileName(widget.unitsList[i].bulletin, widget.unitsList[i].mountType, widget.unitsList[i].disconnect);
//if(fileName != null) {
singleLineImages.add(
Image.asset("images/SD_Files_2100/$fileName.jpg", height: 400.0, width: 200.0,));
//}
}
}
return singleLineImages;
}
I am getting the filename from getFileName() method which is using the database.
getfileName(String bulletin, String mountType, String disconnect)async {
fileNameList = await db.getSDfileName(bulletin, disconnect, mountType);
fileName = fileNameList[0]['FileName'];
print("filename: $fileName");
}
Now, after calling the getFileName(), the program is not waiting for the fileName and proceeding further, which takes filename as null. The filename is obtained correctly after the Image.asset code. Is there any way, so that the program waits untill it gets the proper filename?
Start fetching the list in initState() and call setState when the list is fetched, to do this asynchronously. Below you can find a simplified example of this process. Also note the await statement before get Filename. This makes sure you return to that piece of code after is is done executing.
class ListPage extends StatefulWidget {
#override
_ListPageState createState() => _ListPageState();
}
class _ListPageState extends State<ListPage> {
// This should actually be a List<MyClass> instead of widgets.
List<Widget> _list;
#override
void initState() {
super.initState();
_fetchList();
}
Future _fetchList() async {
List<Widget> singleLineImages = new List();
List unit;
for (int i = 0; i <= widget.unitsList.length-1; i++){
for (int j = 1; j <= int.parse(widget.unitsList[i].quantity); j++){
print("${widget.unitsList[i].bulletin}, ${widget.unitsList[i].mountType}, ${widget.unitsList[i].disconnect}");
String fileName = await getfileName(widget.unitsList[i].bulletin, widget.unitsList[i].mountType, widget.unitsList[i].disconnect);
singleLineImages.add(
Image.asset("images/SD_Files_2100/$fileName.jpg", height: 400.0, width: 200.0,));
}
}
// call setState here to set the actual list of items and rebuild the widget.
setState(() {
_list = singleLineImages;
});
}
#override
Widget build(BuildContext context) {
// Build the list, or for example a CircularProcessIndicator if it is null.
}
}
Sidenote: you are making a lot of calls to the database, which is probably inefficient. Try to get the required data in a single db call. But that is another topic.
Keep Future<Widget> _list; field in your class.
Add _list = _fetchList(); in the initState() function.
Also note that _fetchList should return Future<Widget> in this case.
Use FutureBuilder in your build function.
Edit: I've edited the code below to feature the method that fetches the data along with the widgets that build the train estimates (replacing any API information along the way with "API_URL" and "API_STOP_ID"). I hope this even better helps us figure out the problem! I really appreciate any information anyone can give -- I've been working very hard on this project! Thank you all again!
Original post:
I have a ListView of ListTiles that each have a trailing widget which builds train arrival estimates in a new Text widget. These trailing widgets are updated every five seconds (proven by print statements). As a filler for when the app is fetching data from the train's API, it displays a "no data" Text widget which is built by _buildEstimatesNull().
However, the problem is that "no data" is still being shown even when the app has finished fetching data and _isLoading = false (proven by print statements). Still, even if that was solved, the train estimates would become quickly outdated, as the trailing widgets are updating every five seconds on their own but this would not be reflected in the actual app as the widgets were built on page load. Thus, I need a way to rebuild those trailing widgets whenever they fetch new information.
Is there a way to have Flutter automatically rebuild the ListTile's trailing widget every five seconds as well (or whenever _buildEstimatesS1 is updated / the internals of the trailing widget is updated)?
class ShuttleApp extends StatefulWidget {
#override
State<StatefulWidget> createState() {
return new ShuttleState();
}
}
class ShuttleState extends State<ShuttleApp> {
#override
Widget build(BuildContext context) {
return new MaterialApp(
home: new HomeScreen(),
);
}
}
class HomeScreen extends StatefulWidget {
#override
State<StatefulWidget> createState() {
return new HomeState();
}
}
class HomeState extends State<HomeScreen> {
var _isLoading = true;
void initState() {
super.initState();
_fetchData();
const fiveSec = const Duration(seconds: 5);
new Timer.periodic(fiveSec, (Timer t) {
_fetchData();
});
}
var arrivalsList = new List<ArrivalEstimates>();
_fetchData() async {
arrivalsList.clear();
stopsList.clear();
final url = "API_URL";
print("Fetching: " + url);
final response = await http.get(url);
final busesJson = json.decode(response.body);
if (busesJson["service_id"] == null) {
globals.serviceActive = false;
} else {
busesJson["ResultSet"]["Result"].forEach((busJson) {
if (busJson["arrival_estimates"] != null) {
busJson["arrival_estimates"].forEach((arrivalJson) {
globals.serviceActive = true;
final arrivalEstimate = new ArrivalEstimates(
arrivalJson["route_id"], arrivalJson["arrival_at"], arrivalJson["stop_id"]
);
arrivalsList.add(arrivalEstimate);
});
}
});
}
setState(() {
_isLoading = false;
});
}
Widget _buildEstimateNull() {
return new Container(
child: new Center(
child: new Text("..."),
),
);
}
Widget _buildEstimateS1() {
if (globals.serviceActive == false) {
print('serviceNotActive');
_buildEstimateNull();
} else {
final String translocStopId = "API_STOP_ID";
final estimateMatches = new List<String>();
arrivalsList.forEach((arrival) {
if (arrival.stopId == translocStopId) {
estimateMatches.add(arrival.arrivalAt);
}
});
estimateMatches.sort();
if (estimateMatches.length == 0) {
print("zero");
return _buildEstimateNull();
} else {
return new Container(
child: new Center(
child: new Text(estimateMatches[0]),
),
);
}
}
}
#override
Widget build(BuildContext context) {
return new Scaffold(
backgroundColor: const Color(0xFF171717),
appBar: new AppBar(),
body: new DefaultTextStyle(
style: new TextStyle(color: const Color(0xFFaaaaaa),),
child: new ListView(
children: <Widget>[
new ListTile(
title: new Text('S1: Forest Hills',
style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
subtitle: new Text('Orange Line'),
contentPadding: new EdgeInsets.symmetric(vertical: 16.0, horizontal: 16.0),
trailing: _isLoading ? _buildEstimateNull() : _buildEstimateS1(),
),
],
),
)
);
}
class ArrivalEstimates {
final String routeId;
final String arrivalAt;
final String stopId;
ArrivalEstimates(this.routeId, this.arrivalAt, this.stopId);
}
Thank you so much in advance for any help you can give! I really super appreciate it! :)
There are a few ways you could tackle this. It is slightly difficult however to tell what's going on without seeing a bit more of your code - specifically how you're getting the data and what you're doing with it. But I think I can give you a sufficient answer anyways.
The simple way of doing this is to either:
Have a StatefulWidget which keeps track of the build estimates for all of the items in the list. It should request data from your API, get the results, and then call setState(() => this.listData = data);. The call to setState is what tells the widget that it needs to rebuild.
Have a StatefulWidget for each item in the list. They would all each perform an API request every 5 seconds, get the results, and then each would call setState(() => this.itemData = data);. This means multiple calls to the API etc.
The advantage of #1 is that you can batch API calls, whereas the advantage to #2 is that your build would change less overall (although the way flutter works, this would be pretty minimal)... so I would probably go with #1 if possible.
However, there is a better way of doing this!
The better way of doing this is to have some sort of API Manager (or whatever you want to call it) which handles the communication with your API. It probably would live higher up in your widget tree and would be started/stopped with whatever logic you want. Depending on how far up the widget tree is, you could either pass it into each child or more likely hold it in an InheritedWidget which could then be used to retrieve it from each list element or from the overall list.
The API manager would provide various streams - either with a bunch of named fields/methods or with a getStream(id) sort of structure depending on your API.
Then, within your various list elements, you would use StreamBuilder widgets to build each of the elements based on the data - by using a StreamBuilder you get a ConnectionState object that lets you know whether the stream has received any data yet so you can choose to show an isLoading type widget instead of the one that shows data.
By using this more advanced method, you get:
Maintainability
If your API changes, you only have to change the API manager
You can write better testing as the API interactions and the UI interactions are separated
Extensibility
If you, later on, use push notifications for updates rather than pinging a server every 5 seconds, that can be incorporated into the API manager so that it can simply update the stream without touching the UI
EDIT: as per OP's comments, they have already implemented more or less the first suggestion. However, there are a few problems with the code. I'll list them below and I've posted the code with a couple of changes.
The arrivalsList should be replaced each time a new build is done rather than simply being changed. This is because dart compares the lists and if it finds the same list, it doesn't necessarily compare all of the elements. Also, while changing it in the middle of a function isn't necessarily going to cause problems, it's generally better to use a local variable and then change the value at the end. Note that the member is actually set within setState.
If serviceActive == false, the return was missed from return _buildEstimateNull();.
Here's the code:
class HomeState extends State<HomeScreen> {
var _isLoading = true;
void initState() {
super.initState();
_fetchData();
const fiveSec = const Duration(seconds: 5);
new Timer.periodic(fiveSec, (Timer t) {
_fetchData();
});
}
var arrivalsList = new List<ArrivalEstimates>();
_fetchData() async {
var arrivalsList = new List<ArrivalEstimates>(); // *********** #1
stopsList.clear();
final url = "API_URL";
print("Fetching: " + url);
final response = await http.get(url);
final busesJson = json.decode(response.body);
if (busesJson["service_id"] == null) {
print("no service id");
globals.serviceActive = false;
} else {
busesJson["ResultSet"]["Result"].forEach((busJson) {
if (busJson["arrival_estimates"] != null) {
busJson["arrival_estimates"].forEach((arrivalJson) {
globals.serviceActive = true;
final arrivalEstimate = new ArrivalEstimates(
arrivalJson["route_id"], arrivalJson["arrival_at"], arrivalJson["stop_id"]
);
arrivalsList.add(arrivalEstimate);
});
}
});
}
setState(() {
_isLoading = false;
this.arrivalsList = arrivalsList; // *********** #1
});
}
Widget _buildEstimateNull() {
return new Container(
child: new Center(
child: new Text("..."),
),
);
}
Widget _buildEstimateS1() {
if (globals.serviceActive == false) {
print('serviceNotActive');
return _buildEstimateNull(); // ************ #2
} else {
final String translocStopId = "API_STOP_ID";
final estimateMatches = new List<String>();
print("arrivalsList length: ${arrivalsList.length}");
arrivalsList.forEach((arrival) {
if (arrival.stopId == translocStopId) {
print("Estimate match found: ${arrival.stopId}");
estimateMatches.add(arrival.arrivalAt);
}
});
estimateMatches.sort();
if (estimateMatches.length == 0) {
print("zero");
return _buildEstimateNull();
} else {
return new Container(
child: new Center(
child: new Text(estimateMatches[0]),
),
);
}
}
}
#override
Widget build(BuildContext context) {
return new Scaffold(
backgroundColor: const Color(0xFF171717),
appBar: new AppBar(),
body: new DefaultTextStyle(
style: new TextStyle(color: const Color(0xFFaaaaaa),),
child: new ListView(
children: <Widget>[
new ListTile(
title: new Text('S1: Forest Hills',
style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
subtitle: new Text('Orange Line'),
contentPadding: new EdgeInsets.symmetric(vertical: 16.0, horizontal: 16.0),
trailing: _isLoading ? _buildEstimateNull() : _buildEstimateS1(),
),
],
),
)
);
}
Instead of clearing and re-using the arrivalsList, create a new list every time the data is fetched. Otherwise Flutter is unable to detect if the list has changed.
Also, the code would clearer if you called setState whenever you change the list.
_fetchData() async {
final url = "API_URL";
print("Fetching: " + url);
final response = await http.get(url);
final busesJson = json.decode(response.body);
if (busesJson["service_id"] == null) {
globals.serviceActive = false;
setState(() {
_isLoading = false;
});
} else {
final newArrivalsList = new List<ArrivalEstimates>();
busesJson["ResultSet"]["Result"].forEach((busJson) {
if (busJson["arrival_estimates"] != null) {
busJson["arrival_estimates"].forEach((arrivalJson) {
globals.serviceActive = true;
final arrivalEstimate = new ArrivalEstimates(
arrivalJson["route_id"], arrivalJson["arrival_at"], arrivalJson["stop_id"]
);
newArrivalsList.add(arrivalEstimate);
});
}
});
setState(() {
arrivalsList = newArrivalsList;
_isLoading = false;
});
}
}
A few side notes:
I'm not sure if you actually want to clear the list before you fetch the data. If the state was updated properly, that would cause a flicker every 5 seconds.
I'm not sure if you simplified the code, but calling the _fetchData method every five seconds may become a problem if the network is slow.
If you are certain that you want a child widget to rebuild every time you call setState() and it is stubbornly refusing, you can give it a UniqueKey(). This will ensure that when setState() triggers a rebuild the child widget keys will not match, the old widget will be popped and disposed of, and, the new widget will replace it in the widget tree.
Note that this is using keys in sort of the opposite way for which they were intended (to reduce rebuilding) but if something beyond your control is hindering necessary rebuilds then this is a simple, built-in way to achieve the desired goal.
Here is a very helpful Medium article on keys from one the Flutter team members, Emily Fortuna:
https://medium.com/flutter/keys-what-are-they-good-for-13cb51742e7d
I am not sure if this is what your looking for but and im probably late on this but i believe you can use a change notifier efficiently to achieve this. Basically a change notifier is hooked to your backed logic() for instance an api data fetch. A widget is then registered with a change notifier of the same type as the change notifier provider. In event of data change, the widgets registered with the change notifier will be rebuild.
For instance
// extend the change notifier class
class DataClass extends ChangeNotifier {
....
getData(){
Response res = get('https://data/endpoint')
notifyListeners()
}
void onChange() {
notifyListeners();
}
....
}
Every time there is change in data you call the notifyListeners() that will trigger rebuild of consuming widgets.
Register you widget with a changenotifier
class View extends StatefulWidget {
Widget create(BuildContext context) {
return ChangeNotifierProvider<ModelClass>(
builder: (context) => DataClass(auth: auth),
child: Consumer<ModelClass>(
builder: (context, model, _) => View(model: model),
),
);
}
}
You can also user a Consumer for the same. Get more on this from the Documentation
Not sure since I have just started building things with Flutter and Dart. If anyone can take a look at the code and can share inputs on:
How to display listview having fixed number of items, lets say in my example we are fetching 100 items
How to implement paging, lets say initially I want to fetch 1st page and then while scrolling page 2nd and so on.
Issues:
In current implementation, I am finding 2 issues:
Able to scroll endlessly at bottom
Finding exception in logcat output:
03-15 06:14:36.464 3938-3968/com.technotalkative.flutterfriends I/flutter: Another exception was thrown: RangeError (index): Invalid value: Not in range 0..99, inclusive: 100
I have posted the same issue on my Github repository: https://github.com/PareshMayani/Flutter-Friends/issues/1
Would appreciate if you contribute to this repo!
That is beacuse you are using ListView.builder which actually renders an infinite list when itemCount is not specified. Try specifying itemCount to 100.
For pagination, the simplest solution with a ListView.builder would be to show a refresh widget when the list has reached its end and initiate a refresh api call, and then add new items to the list and increase item count.
Example:
class Example extends StatefulWidget {
#override
_ExampleState createState() => new _ExampleState();
}
class _ExampleState extends State<Example> {
// initial item count, in your case `_itemCount = _friendList.length` initially
int _itemCount = 10;
void _refreshFriendList() {
debugPrint("List Reached End - Refreshing");
// Make api call to fetch new data
new Future<dynamic>.delayed(new Duration(seconds: 5)).then((_){
// after new data received
// add the new data to the existing list
setState(() {
_itemCount = _itemCount + 10; // update the item count to notify newly added friend list
// in your case `_itemCount = _friendList.length` or `_itemCount = _itemCount + newData.length`
});
});
}
// Function that initiates a refresh and returns a CircularProgressIndicator - Call when list reaches its end
Widget _reachedEnd(){
_refreshFriendList();
return const Padding(
padding: const EdgeInsets.all(20.0),
child: const Center(
child: const CircularProgressIndicator(),
),
);
}
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(),
// ListView Builder
body: new ListView.builder(
itemCount: _itemCount + 1,
itemBuilder: (_, index) {
final Widget listTile = index == _itemCount // check if the list has reached its end, if reached end initiate refresh and return refresh indicator
? _reachedEnd() // Initiate refresh and get Refresh Widget
: new Container(
height: 50.0,
color: Colors.primaries[index%Colors.primaries.length],
);
return listTile;
},
),
);
}
}
Hope that helps!
Note: I'm not claiming this is the best way or is optimal but this is one of the ways of doing it. There is an example social networking app of git which does it in a different way, you can take a look at it here.
I'm trying to display the contents of my HashMap values in a ListView.builder widget. Is there a way to do this? With a List I could simply use the index, but how would that work with a HashMap without making a List out of it?
The keys of the map are strings and the values are maps with the data to display.
Its a little late but You could also try this.
Map values = snapshot.data;
return new ListView.builder(
itemCount: values.length,
itemBuilder: (BuildContext context, int index) {
String key = values.keys.elementAt(index);
return new Column(
children: <Widget>[
new ListTile(
title: new Text("$key"),
subtitle: new Text("${values[key]}"),
),
new Divider(
height: 2.0,
),
],
);
},
);
for a more detailed example check this out
https://kodestat.gitbook.io/flutter/39-flutter-listviewbuilder-using-dart-maps
Just make a list from the keys and then get the value using the index to get the map key and use it to get the map value
var keys = myMap.keys.toList();
var val = myMap[keys[idx]];
it is possible, you can do something like this
map.forEach((key, value) {
// here you can write your logic using "Value object",
// make new object of your list view item and
// add it to it's builder list using
setState(() {
_builderList.insert(0, itemObject);
});
});
or you can try
final list = map.values.toList(growable: {true/false});
// play with your list
Just use inside the listview builder yourlistname[index ]['keyname' ], that works for me.