How to retrieve Firestore data using flutter - flutter

Question

I was now trying for days to retrieve my firestore values, but no luck so posting it here.
I have a Firestore database and some data. I want to retrieve this with the help of Flutter.
This is what I have been doing.
So I have a Flutter screen where it shows a simple 3-dot dropdown in the AppBar.
It has two options: edit and cancel.
What I want is, when I press edit, it should open a new screen and should pass the data that I retrieved from firestore.
This is where I have edit and cancel dropdown (3 dots) and calling the a function (to retrieve data and open the new screen).
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
centerTitle: true,
title: Text(widget.news.headline.toUpperCase()),
actions: <Widget>[
PopupMenuButton<String>(
onSelected: (value) {
_open_edit_or_delete(value); // caling the function here
},
itemBuilder: (BuildContext context) {
return {'Edit', 'Delete'}.map((String choice) {
return PopupMenuItem<String>(
value: choice,
child: Text(choice),
);
}).toList();
},
),
],
),
body: _get_particular_news(widget.news),
);
}
and this is the open_edit_or_delete function it is calling. But it doesn't open up (navigate) to the screen I am calling.
open_edit_or_delete(String selectedOption) {
News news;
Visibility(
visible: false,
child: StreamBuilder(
stream: FireStoreServiceApi().getNews(),
builder: (BuildContext context, AsyncSnapshot<List<News>> snapshot) {
if (snapshot.hasError || !snapshot.hasData) {
Navigator.push(
context, MaterialPageRoute(builder: (_) => FirstScreen(news:news)));
return null;
} else {
return ListView.builder(
itemCount: snapshot.data.length,
itemBuilder: (BuildContext context, int index) {
news = snapshot.data[index];
},
);
}
},
));
}
And in case you need the FireStoreServiceApi().getNews(), here it is as well.
// get the news
Stream<List<News>> getNews() {
return _db.collection("news").snapshots().map(
(snapshot) => snapshot.documents
.map((doc) => News.fromMap(doc.data, doc.documentID))
.toList(),
) ;
}
Can someone please help me?

Answer 1

You are not passing data correctly to your fromMap method.
You can access data using doc.data['']
If you have data and documentID property in it then following will work.
News.fromMap(doc.data.data, doc.data.documentID))
I don't know your fromMap method and i also don't what your snapshot contains, if this did not work for you then add them too.