I have a flutter app where a list is generated with ListView.Builder, and where the itemCount is the number of documents in a firestore collection.
When I add a document to the collection I can see that the value snapshot.data.documents.length changes by printing it, but the the itemCount does not change, which causes the following error:
Invalid value: Not in range 0..17, inclusive: 18
Here is a GitHub thread I created about the same problem: https://github.com/flutter/flutter/issues/39206
And here is the code for the page in question, and the list i'm getting the error from is the one in the StreamBuilder close to the bottom:
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
/*
Visar kontaktinformation
*/
class Contact extends StatefulWidget {
@override
_ContactState createState() => _ContactState();
}
class _ContactState extends State<Contact> {
_hasDesc(desc) {
if (desc == '') {
return false;
} else {
return true;
}
}
String sortby = 'namn';
bool decending = false;
var showInfo;
TextEditingController controller = new TextEditingController();
String filter;
@override
void initState() {
super.initState();
controller.addListener(() {
setState(() {
filter = controller.text.toLowerCase(); //Gör om till gemener för att inte vara skiftlägeskänslig
});
});
}
@override
void dispose() {
controller.dispose();
super.dispose();
}
Widget _personer(context, DocumentSnapshot document, index) {
//Skapar lista från databasen med kontaktinformation
//Denna lista måste vara i rätt ordning i databasen
final info = List<String>.from(document['info']);
//Om sökrutan är tom visas alla personer, om inte så visas bara de som matchar filtret
if (filter == null ||
filter == '' ||
document['namn'].toLowerCase().contains(filter) ||
document['beskrivning'].toLowerCase().contains(filter)) {
return Column(
children: <Widget>[
ListTile(
onTap: () {
setState(() {
for (int i = 0; i < showInfo.length; i++) {
if (i != index) {
showInfo[i] = false; // för att enbart ett kort ska vara expanderat åt gången
}
}
showInfo[index] = !showInfo[index];
});
},
title: Padding(
padding: const EdgeInsets.fromLTRB(0, 4, 0, 4),
child: Column(
children: <Widget>[
Text(
document['namn'],
textAlign: TextAlign.center,
style: Theme.of(context).textTheme.headline,
),
Visibility(
visible: _hasDesc(document['beskrivning']),
child: Text(
document['beskrivning'],
textAlign: TextAlign.center,
style: Theme.of(context).textTheme.subtitle.copyWith(fontSize: 20),
),
),
Visibility(
visible: showInfo[index],
child: ListView.builder(
//Bygger lista med kontaktinfo för varje person
physics: NeverScrollableScrollPhysics(),
shrinkWrap: true,
itemCount: info.length,
itemBuilder: (context, index) {
return Padding(
padding: const EdgeInsets.only(top: 5),
child: ButtonTheme(
child: GestureDetector(
onTap: () {
Clipboard.setData(ClipboardData(text: info[index]));
//skapar snackbar
final copiedTextSnackBar = SnackBar(
content: Text('"${info[index].replaceAll('/', '')}" har kopierats'),
action: SnackBarAction(
label: 'Okej',
onPressed: () => Scaffold.of(context).hideCurrentSnackBar(),
),
);
//Stänger eventuell snackbar och viar en ny
Scaffold.of(context).hideCurrentSnackBar();
Scaffold.of(context).showSnackBar(copiedTextSnackBar);
},
child: Text(
info[index].replaceAll('/', '\n'),
textAlign: TextAlign.center,
style: Theme.of(context).textTheme.body1.copyWith(
fontSize: 16,
color: Color(0xff555555),
),
),
),
),
);
},
),
),
],
),
),
),
Divider(
color: Colors.black,
),
],
);
} else {
return SizedBox(
height: 0, //Visar ingenting om filtret inte stämmer
);
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: Column(
children: <Widget>[
Row(
children: <Widget>[
Flexible(
child: TextField(
decoration: InputDecoration(
contentPadding: EdgeInsets.fromLTRB(20, 10, 20, 10),
hintText: 'Sök',
border: InputBorder.none,
),
controller: controller,
),
),
Text('Sortera: ', style: TextStyle(fontSize: 16, color: Color(0xff555555)),),
DropdownButton<String>(
value: sortby,
onChanged: (String newValue) {
setState(() {
sortby = newValue;
});
},
items: [
DropdownMenuItem(
value: 'namn',
child: Text('Namn'),
),
DropdownMenuItem(
value: 'beskrivning',
child: Text('Titel'),
)
]
),
Stack(
children: <Widget>[
Visibility(
visible: decending,
child: IconButton(
icon: Icon(Icons.arrow_upward),
onPressed: () => setState(() {
decending = false;
}),
),
),
Visibility(
visible: !decending,
child: IconButton(
icon: Icon(Icons.arrow_downward),
onPressed: () => setState(() {
decending = true;
}),
),
)
],
)
],
),
Expanded(
child: Container(
child: StreamBuilder(
stream: Firestore.instance.collection('kontakt').orderBy(sortby, descending: decending).snapshots(), //Hämtar data från databas
builder: (context, snapshot) {
//För att inte skriva över existerande lista:
if (showInfo == null) {
//Listan genereras här för att slippa kalla på databasen två ggr
showInfo = List.generate(snapshot.data.documents.length, (index) => false);
}
if (!snapshot.hasData) {
return Container();
} else if (snapshot.hasData) {
print(snapshot.data.documents.length);
return ListView.builder(
itemCount: snapshot.data.documents.length,
itemBuilder: (context, index) =>
_personer(context, snapshot.data.documents[index], index),
);
} else {
return Center(
child: Text("Error"),
);
}
},
),
),
),
],
),
);
}
}
