Another exception was thrown: FormatException: Invalid number (at character 1) - flutter

Question

Why does the error Another exception was thrown: FormatException: Invalid number (at character 1) occur on my screen for a few microseconds before all is back to normal. Sometimes it doesn't even occur. Below is my StreamBuilder function:
_delivered() {
print('In the delivered function:${resId},${customerId}, ');
return StreamBuilder<QuerySnapshot>(
stream: Firestore.instance
.collection('restaurants')
.document(resId)
.collection('customers')
.document(customer)
.collection('orders')
.where('deliveryTime', isGreaterThan: '')
.snapshots(),
builder: (context, snapshot) {
print('Does snapshop have data? ${snapshot.hasData}');
if (!snapshot.hasData) return Container();
List deliveredListFromServer = snapshot.data.documents;
return Expanded(
child: ListView(
shrinkWrap: true,
children: deliveredListFromServer.map((item) {
print('document id: ${item.documentID}');
return InkWell(
child: SizedBox(
height: 50,
child: Row(
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
SizedBox(
width: 80,
child: Text(
item['orderBy']['username'],
textAlign: TextAlign.center,
overflow: TextOverflow.ellipsis,
style: TextStyle(fontWeight: FontWeight.bold),
),
),
SizedBox(
width: 5,
),
Expanded(
child: ListView(
scrollDirection: Axis.horizontal,
children: item['order'].map<Widget>((item) {
return SizedBox(
width: 80,
child: Align(
alignment: Alignment.centerLeft,
child: Text(
'${item['qty']} ${item['drinkName']}',
overflow: TextOverflow.ellipsis,
),
),
);
}).toList(),
), //
),
SizedBox(
width: 5,
),
SizedBox(
width: 60,
child: Text(DateFormat('h:mm a').format(
DateTime.fromMillisecondsSinceEpoch(
int.parse(item['deliveryTime'])))),
)
],
),
),
onTap: () {
_deliveredDetail(item);
},
);
}).toList(),
),
);
});
}
This is my console:
I/flutter (11506): In the delivered function:XufIsxA8a24lLhO6gTr1,zMrQmcoQwci9bVVRo6tx,
I/flutter (11506): Does snapshop have data? true
I/flutter (11506): document id: 1579534059562
I/flutter (11506): document id: 1579595374166
I/flutter (11506): Another exception was thrown: FormatException: Invalid number (at character 1)
I/flutter (11506): Does snapshop have data? true
I/flutter (11506): document id: 1579534059562
From the console, I don't even understand why it's bringing document id: 1579595374166 from the database. Only document id: 1579534059562 has a deliveryTime set. The database has 6 records, only one has a deliveryTime set. Others are empty "" strings.
So after a few milliseconds, everything works as expected i.e. the proper UI with only one item for the database showing on the screen. It looks like everything is back to normal the second time the stream returns only one document. In fact, the only time it doesn't bring the red screen is when the console looks like this:
I/flutter (11506): In the delivered function:XufIsxA8a24lLhO6gTr1,zMrQmcoQwci9bVVRo6tx,
I/flutter (11506): Does snapshop have data? false
I/flutter (11506): Does snapshop have data? true
I/flutter (11506): document id: 1579534059562
This also means the streamBuilder is passing incorrect data to the list (and probable source of error). Why is the query returning the wrong results sometimes?!

Answer 1

This error occurs when you are fetching a data which is null, I encountered the same issue and was able to solve it by removing that null data from my firestore database.
I would suggest you check the data in the collection from where you are fetching the list, one of the fields must be null there.

Answer 2

My answer may not be applicable to this instance, but I have also got the same error "Invalid number (at character 1)", the place where I get the error points me to where I have used the variable name of my TextEditingController
The problem with my case was that I have already used a TextEditingController with the same name (also not as a private variable) in another point of my application and have not disposed it after using.
After I disposed all of my TextEditingControllers my problem got solved !

Answer 3

if an error occurs in the parameter, you can add an isEmpty condition for your parameter value.
ex :
// define currency
final _controller = TextEditingController(); static const _locale = 'id'; static const _symbol = 'Rp. '; String _formatNumber(String s) =>
NumberFormat.decimalPattern(
_locale,
).format(s.isEmpty ? 0 : int.parse(s)); String get _currency =>
NumberFormat.compactSimpleCurrency( locale: _locale, name: _symbol).currencySymbol;
//textfield
TextfieldWidget( prefixText: Text(_currency, style: Theme.of(context).textTheme.subtitle1),
controller: _controller,
onChanged: (string) {
string =
'${_formatNumber(string.replaceAll(',', ''))}';
_controller.value = TextEditingValue(
text: string,
selection: TextSelection.collapsed(
offset: string.length ?? null),
);
}, ),

Answer 4

Ensure that you check that the value is not equal to "" or null
if (value != "")