"Closure call with mismatched arguments", but I can't figure out why - flutter

Question

I'm getting a "Closure call with mismatched arguments"-error when I try to submit a form in my Flutter app, and I don't have a single clue why it's happening. It seems to have issues with my handleInputSave-function, however I'm only calling it once and I've confirmed multiple times that the arguments are correct.
The complete error:
I/flutter ( 6655): ══╡ EXCEPTION CAUGHT BY GESTURE ╞═══════════════════════════════════════════════════════════════════
I/flutter ( 6655): The following NoSuchMethodError was thrown while handling a gesture:
I/flutter ( 6655): Closure call with mismatched arguments: function '_MetricState.build.<anonymous closure>'
I/flutter ( 6655): Receiver: Closure: (dynamic) => bool
I/flutter ( 6655): Tried calling: _MetricState.build.<anonymous closure>()
I/flutter ( 6655): Found: _MetricState.build.<anonymous closure>(dynamic) => bool
I/flutter ( 6655):
I/flutter ( 6655): When the exception was thrown, this was the stack:
I/flutter ( 6655): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
I/flutter ( 6655): #1 NumberInputState.build.<anonymous closure> (package:greeklibrary/components/Select/Metric/numberinput.dart:60:26)
I/flutter ( 6655): #2 FormFieldState._validate (package:flutter/src/widgets/form.dart)
I/flutter ( 6655): #3 FormFieldState.validate.<anonymous closure> (package:flutter/src/widgets/form.dart:364:7)
I/flutter ( 6655): #4 State.setState (package:flutter/src/widgets/framework.dart:1141:30)
I/flutter ( 6655): #5 FormFieldState.validate (package:flutter/src/widgets/form.dart:363:5)
I/flutter ( 6655): #6 FormState._validate (package:flutter/src/widgets/form.dart:203:25)
I/flutter ( 6655): #7 FormState.validate (package:flutter/src/widgets/form.dart:197:12)
I/flutter ( 6655): #8 _MetricState.build.<anonymous closure> (package:greeklibrary/components/Select/Metric/metric.dart:48:51)
I/flutter ( 6655): #9 _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:654:14)
I/flutter ( 6655): #10 _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:729:32)
I/flutter ( 6655): #11 GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
I/flutter ( 6655): #12 TapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:365:11)
I/flutter ( 6655): #13 TapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:275:7)
I/flutter ( 6655): #14 PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:455:9)
I/flutter ( 6655): #15 PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:75:13)
I/flutter ( 6655): #16 PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:102:11)
I/flutter ( 6655): #17 GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:218:19)
I/flutter ( 6655): #18 GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22)
I/flutter ( 6655): #19 GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7)
I/flutter ( 6655): #20 GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:102:7)
I/flutter ( 6655): #21 GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:86:7)
I/flutter ( 6655): #25 _invoke1 (dart:ui/hooks.dart:263:10)
I/flutter ( 6655): #26 _dispatchPointerDataPacket (dart:ui/hooks.dart:172:5)
I/flutter ( 6655): (elided 3 frames from package dart:async)
I/flutter ( 6655):
I/flutter ( 6655): Handler: "onTap"
I/flutter ( 6655): Recognizer:
I/flutter ( 6655): TapGestureRecognizer#8abdf
I/flutter ( 6655): ════════════════════════════════════════════════════════════════════════════════════════════════════
The Metric (parent) widget:
import "package:flutter/material.dart";
import 'package:greeklibrary/styles/variables.dart';
import "./numberinput.dart";
class Metric extends StatefulWidget {
#override
_MetricState createState() => _MetricState();
}
class _MetricState extends State<Metric> {
final _formKey = GlobalKey<FormState>();
var _formData = {};
void handleInputSave(String name, String value) {
print("called");
setState(() => _formData[name] = value);
}
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: colorPrimary,
body: Container(
padding: const EdgeInsets.symmetric(horizontal: 25.0),
child: Center(
child: Form(
key: _formKey,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
NumberInput(
name: "book",
defaultValue: "1",
validator: (value) =>
!RegExp(r"^[0-9]$").hasMatch(value) &&
!RegExp(r"^[1-2][0-4]$").hasMatch(value),
onSaved: (String name, String value) =>
handleInputSave(name, value),
),
SizedBox(
height: 20.0,
),
RaisedButton(
child: Text("Ἀγε!"),
onPressed: () {
print(_formKey.currentState.validate());
if (_formKey.currentState.validate()) {
// _formKey.currentState.save();
print("succeeded");
// Navigator.of(context).pushNamed("/loading");
}
})
],
),
),
),
),
);
}
}
The NumberInput (child) widget:
import "package:flutter/material.dart";
class NumberInput extends StatefulWidget {
final String name;
final String defaultValue;
final Function validator;
final Function onSaved;
NumberInput({this.name, this.defaultValue, this.validator, this.onSaved});
#override
NumberInputState createState() => NumberInputState();
}
class NumberInputState extends State<NumberInput> {
String value;
#override
void initState() {
super.initState();
setState(() => value = widget.defaultValue);
print(widget.onSaved);
}
Widget build(BuildContext context) {
return Row(
children: <Widget>[
ButtonTheme(
minWidth: 14.0,
buttonColor: Color.fromRGBO(0, 0, 0, 0.0),
child: RaisedButton(
child: Text(
"-",
style: TextStyle(fontSize: 32.0),
),
elevation: 1,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(18.0),
),
onPressed: () {
setState(() {
if (int.parse(value) > 1) {
value = (int.parse(value) - 1).toString();
}
});
},
),
),
SizedBox(
width: 16.0,
),
Flexible(
child: TextFormField(
keyboardType: TextInputType.number,
decoration: InputDecoration(
labelText: "Vul een boeknummer in",
),
controller: TextEditingController(text: value),
validator: (value) {
if (widget.validator()) {
return "Vul alstublieft een (geldig) booknummer in.";
}
return null;
},
onSaved: (value) {
widget.onSaved(widget.name, value);
},
),
),
SizedBox(
width: 16.0,
),
ButtonTheme(
minWidth: 14.0,
buttonColor: Color.fromRGBO(0, 0, 0, 0.0),
child: RaisedButton(
child: Text(
"+",
style: TextStyle(fontSize: 32.0),
),
elevation: 1,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(18.0),
),
onPressed: () {
setState(() => value = (int.parse(value) + 1).toString());
},
),
),
],
);
}
}

Answer 1

You forgot to put value as parameter for your validator
You can copy paste run full code below
code snippet
if (widget.validator(value)) {
return "Vul alstublieft een (geldig) booknummer in.";
}
demo
full code
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
});
}
#override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child: Column(
// Column is also a layout widget. It takes a list of children and
// arranges them vertically. By default, it sizes itself to fit its
// children horizontally, and tries to be as tall as its parent.
//
// Invoke "debug painting" (press "p" in the console, choose the
// "Toggle Debug Paint" action from the Flutter Inspector in Android
// Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
// to see the wireframe for each widget.
//
// Column has various properties to control how it sizes itself and
// how it positions its children. Here we use mainAxisAlignment to
// center the children vertically; the main axis here is the vertical
// axis because Columns are vertical (the cross axis would be
// horizontal).
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Expanded(flex:1, child: Metric()),
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.display1,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
class Metric extends StatefulWidget {
#override
_MetricState createState() => _MetricState();
}
class _MetricState extends State<Metric> {
final _formKey = GlobalKey<FormState>();
var _formData = {};
void handleInputSave(String name, String value) {
print("called");
setState(() => _formData[name] = value);
}
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,//colorPrimary,
body: Container(
padding: const EdgeInsets.symmetric(horizontal: 25.0),
child: Center(
child: Form(
key: _formKey,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
NumberInput(
name: "book",
defaultValue: "1",
validator: (value) =>
!RegExp(r"^[0-9]$").hasMatch(value) &&
!RegExp(r"^[1-2][0-4]$").hasMatch(value),
onSaved: (String name, String value) =>
handleInputSave(name, value),
),
SizedBox(
height: 20.0,
),
RaisedButton(
child: Text("Ἀγε!"),
onPressed: () {
print(_formKey.currentState.validate());
if (_formKey.currentState.validate()) {
// _formKey.currentState.save();
print("succeeded");
// Navigator.of(context).pushNamed("/loading");
}
})
],
),
),
),
),
);
}
}
class NumberInput extends StatefulWidget {
final String name;
final String defaultValue;
final Function validator;
final Function onSaved;
NumberInput({this.name, this.defaultValue, this.validator, this.onSaved});
#override
NumberInputState createState() => NumberInputState();
}
class NumberInputState extends State<NumberInput> {
String value;
#override
void initState() {
super.initState();
setState(() => value = widget.defaultValue);
print(widget.onSaved);
}
Widget build(BuildContext context) {
return Row(
children: <Widget>[
ButtonTheme(
minWidth: 14.0,
buttonColor: Color.fromRGBO(0, 0, 0, 0.0),
child: RaisedButton(
child: Text(
"-",
style: TextStyle(fontSize: 32.0),
),
elevation: 1,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(18.0),
),
onPressed: () {
setState(() {
if (int.parse(value) > 1) {
value = (int.parse(value) - 1).toString();
}
});
},
),
),
SizedBox(
width: 16.0,
),
Flexible(
child: TextFormField(
keyboardType: TextInputType.number,
decoration: InputDecoration(
labelText: "Vul een boeknummer in",
),
controller: TextEditingController(text: value),
validator: (value) {
if (widget.validator(value)) {
return "Vul alstublieft een (geldig) booknummer in.";
}
return null;
},
onSaved: (value) {
widget.onSaved(widget.name, value);
},
),
),
SizedBox(
width: 16.0,
),
ButtonTheme(
minWidth: 14.0,
buttonColor: Color.fromRGBO(0, 0, 0, 0.0),
child: RaisedButton(
child: Text(
"+",
style: TextStyle(fontSize: 32.0),
),
elevation: 1,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(18.0),
),
onPressed: () {
setState(() => value = (int.parse(value) + 1).toString());
},
),
),
],
);
}
}