Flutter Web Unexpected Null Value - flutter

Question

enter image description here I get Unexpected Null value error when switching from Home page to Vehicle Add page. I couldn't understand what caused this.
I tried to run it in debug mode, but it was very confusing in debug mode, I couldn't understand it.
home.dart page
import 'package:Car_Price_App/Pages/category_add.dart';
import 'package:Car_Price_App/Pages/vehicle_add.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
import '../services/auth_service.dart';
class Home extends StatefulWidget {
const Home({super.key});
#override
State<Home> createState() => _HomeState();
}
class _HomeState extends State<Home> {
#override
Widget build(BuildContext context) {
final user = FirebaseAuth.instance.currentUser;
final email = user?.email;
return Scaffold(
appBar: AppBar(
title: Center(child: Text("Sıfır Araçlar ${email?.toUpperCase()}")),
leading: const Icon(Icons.car_rental),
actions: [
IconButton(onPressed: () {
Navigator.push(context, MaterialPageRoute(builder: (context)=> CategoryAdd(gelenEmail: email.toString(),)));
print("giden $email");
}, icon: const Icon(Icons.category)),
IconButton(onPressed: () {
Navigator.push(context, MaterialPageRoute(builder: (context)=> VehicleAdd()));
}, icon: const Icon(Icons.add)),
IconButton(onPressed: () {}, icon: const Icon(Icons.update)),
IconButton(onPressed: () {}, icon: const Icon(Icons.delete)),
],
),
body: Center(
child: Column(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text("Giriş Yapıldı $email"),
const SizedBox(height: 10,),
ElevatedButton(onPressed: (){
AuthService().signOut();
}, child: const Text("Çıkış Yap",),),
],
),
),
);
}
}
vehicle_add.dart page
import 'dart:io';
import 'dart:math';
import 'dart:core';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:currency_text_input_formatter/currency_text_input_formatter.dart';
import 'package:file_picker/file_picker.dart';
import 'package:firebase_storage/firebase_storage.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import '../models/trade_mark_model.dart';
import '../models/type_of_vehicle_model.dart';
import '../models/vehicle_body_type_model.dart';
import '../models/vehicle_model.dart';
import '../models/vehicle_year_model.dart';
class VehicleAdd extends StatefulWidget {
const VehicleAdd({Key? key}) : super(key: key);
#override
State<VehicleAdd> createState() => _VehicleAddState();
}
class _VehicleAddState extends State<VehicleAdd> {
GlobalKey? aracEkleKey = GlobalKey<FormState>();
var db = FirebaseFirestore.instance;
TextEditingController vehicleProperties = TextEditingController();
TextEditingController vehiclePrice = TextEditingController();
String? vasitaTipi = "";
String? kasaTipi = "";
String? marka = "";
String? model = "";
String? yil = "";
PlatformFile? pickedFile;
UploadTask? uploadTask;
Future selectFile() async {
final result = await FilePicker.platform.pickFiles();
if (result == null) return;
setState(() {
pickedFile = result.files.first;
});
}
Future uploadFile() async {
final path = 'aracResimleri/${pickedFile?.name}';
final file = File(pickedFile!.path!);
final ref = FirebaseStorage.instance.ref().child(path);
setState(() {
uploadTask = ref.putFile(file);
});
final snapshot = await uploadTask?.whenComplete(() {});
final urlDownload = await snapshot?.ref.getDownloadURL();
print('Download Link : $urlDownload');
setState(() {
uploadTask = null;
});
}
Stream<List<TypeOfVehicleModel>> readVehicleType() => db.collection("Vasıtalar").snapshots().map((snapshot) => snapshot.docs.map((doc) => TypeOfVehicleModel.fromJson(doc.data())).toList());
Stream<List<VehicleBodyTypeModel>> readBodyType() => db.collection("KasaTipleri").snapshots().map((snapshot) => snapshot.docs.map((doc) => VehicleBodyTypeModel.fromJson(doc.data())).toList());
Stream<List<TradeMarkModel>> readTradeMark() => db.collection("Markalar").snapshots().map((snapshot) => snapshot.docs.map((doc) => TradeMarkModel.fromJson(doc.data())).toList());
Stream<List<VehicleModel>> readVehicleModel() => db.collection("Modeller").snapshots().map((snapshot) => snapshot.docs.map((doc) => VehicleModel.fromJson(doc.data())).toList());
Stream<List<VehicleYearModel>> readVehicleYear() => db.collection("Yıllar").snapshots().map((snapshot) => snapshot.docs.map((doc) => VehicleYearModel.fromJson(doc.data())).toList());
late int _key;
_collapse() {
int? newKey;
do {
_key = Random().nextInt(10000);
} while (newKey == _key);
}
#override
void initState() {
super.initState();
_collapse();
}
#override
Widget build(BuildContext context) {
var screenInfo = MediaQuery.of(context);
final double screenWidth = screenInfo.size.width;
final double screenHeight = screenInfo.size.height;
return Scaffold(
appBar: AppBar(
title: const Text("Araç Ekle"),
),
body: SingleChildScrollView(
child: Padding(
padding: const EdgeInsets.symmetric(horizontal: 30, vertical: 20),
child: Center(
child: Form(
autovalidateMode: AutovalidateMode.onUserInteraction,
key: aracEkleKey,
child: SizedBox(
width: screenWidth / 2,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
FutureBuilder<List<TypeOfVehicleModel>>(
future: readVehicleType().first,
builder: (context, snapshot) {
if (snapshot.hasError) {
return const Text("Something went wrong");
} else if (snapshot.hasData) {
final typeOfVehicle = snapshot.data!;
return ExpansionTile(
key: Key(_key.toString()),
initiallyExpanded: false,
leading: const Icon(Icons.merge_type),
title: const Text("Vasıta Seçiniz"),
children: typeOfVehicle.map(buildTov).toList(),
);
} else {
return const Center(
child: Padding(
padding: EdgeInsets.all(8.0),
child: CircularProgressIndicator(),
),
);
}
},
), // Vasıta Tipi
Text("$vasitaTipi"),
Text("$kasaTipi"),
Text("$marka"),
Text("$model"),
Text("$yil"),
FutureBuilder<List<VehicleBodyTypeModel>>(
future: readBodyType().first,
builder: (context, snapshot) {
if (snapshot.hasError) {
return const Text("Something went wrong");
} else if (snapshot.hasData) {
final bodyType = snapshot.data!;
return ExpansionTile(
key: Key(_key.toString()),
initiallyExpanded: false,
leading: const Icon(Icons.type_specimen),
title: const Text("Kasa Tipi Seçiniz"),
children: bodyType.map(buildBodyType).toList(),
);
} else {
return const Center(
child: Padding(
padding: EdgeInsets.all(8.0),
child: CircularProgressIndicator(),
),
);
}
},
), // Kasatipi
FutureBuilder<List<TradeMarkModel>>(
future: readTradeMark().first,
builder: (context, snapshot) {
if (snapshot.hasError) {
return const Text("Something went wrong");
} else if (snapshot.hasData) {
final tradeMarka = snapshot.data!;
return ExpansionTile(
key: Key(_key.toString()),
initiallyExpanded: false,
leading: const Icon(Icons.branding_watermark),
title: const Text("Marka Seçiniz"),
children: tradeMarka.map(buildTradeMark).toList(),
);
} else {
return const Center(
child: Padding(
padding: EdgeInsets.all(8.0),
child: CircularProgressIndicator(),
),
);
}
},
), //Markalar
FutureBuilder<List<VehicleModel>>(
future: readVehicleModel().first,
builder: (context, snapshot) {
if (snapshot.hasError) {
return const Text("Something went wrong");
} else if (snapshot.hasData) {
final model = snapshot.data!;
return ExpansionTile(
key: Key(_key.toString()),
initiallyExpanded: false,
leading: const Icon(Icons.time_to_leave),
title: const Text("Model Seçiniz"),
children: model.map(buildModel).toList(),
);
} else {
return const Center(
child: Padding(
padding: EdgeInsets.all(8.0),
child: CircularProgressIndicator(),
),
);
}
},
), //Modeller
FutureBuilder<List<VehicleYearModel>>(
future: readVehicleYear().first,
builder: (context, snapshot) {
if (snapshot.hasError) {
return const Text("Something went wrong");
} else if (snapshot.hasData) {
final year = snapshot.data!;
return ExpansionTile(
key: Key(_key.toString()),
initiallyExpanded: false,
leading: const Icon(Icons.calendar_month),
title: const Text(
"Yıl Seçiniz",
),
children: year.map(buildYear).toList(),
);
} else {
return const Center(
child: Padding(
padding: EdgeInsets.all(8.0),
child: CircularProgressIndicator(),
),
);
}
},
), //Yıllar
Padding(
padding: const EdgeInsets.all(8.0),
child: TextFormField(
controller: vehicleProperties,
decoration: const InputDecoration(
labelText: "Araç Özellikleri Giriniz",
suffixText: "Araç Özellikleri Giriniz",
border: OutlineInputBorder(),
),
minLines: 1,
maxLines: screenHeight.toInt(),
),
),
Padding(
padding: const EdgeInsets.all(8.0),
child: TextFormField(
keyboardType: TextInputType.number,
inputFormatters: <TextInputFormatter>[
// for below version 2 use this
FilteringTextInputFormatter.allow(RegExp(
r'\d',
)),
FilteringTextInputFormatter.digitsOnly,
CurrencyTextInputFormatter(
symbol: '₺',
name: "TL",
)
],
controller: vehiclePrice,
decoration: const InputDecoration(
labelText: "Araç Fiyat Giriniz",
suffixText: "Araç Fiyat Giriniz",
border: OutlineInputBorder(),
),
minLines: 1,
maxLines: screenHeight.toInt(),
),
),
Expanded(
child: Image.file(
File(pickedFile!.path!),
width: double.infinity,
fit: BoxFit.cover,
),
),
ElevatedButton.icon(
icon: const Icon(Icons.image),
onPressed: () {
selectFile();
showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: const Text("Araç Resmi Seç"),
content: Text(pickedFile!.name),
actions: [
TextButton(
onPressed: () async {
uploadFile();
},
child: const Center(
child: Text(
"Galeri'den Seç",
style: TextStyle(color: Colors.black, fontSize: 20),
))),
],
);
});
},
label: const Text("Araç Resimi Ekle"),
),
const SizedBox(
height: 30,
),
StreamBuilder<TaskSnapshot>(
stream: uploadTask!.snapshotEvents,
builder: (context, snapshot) {
if (snapshot.hasData) {
final data = snapshot.data!;
double progress = data.bytesTransferred / data.totalBytes;
return SizedBox(
height: 50,
child: Stack(
fit: StackFit.expand,
children: [
LinearProgressIndicator(
value: progress,
color: Colors.green,
backgroundColor: Colors.grey,
),
Center(
child: Text(
'${(100 * progress).roundToDouble()} %',
style: const TextStyle(color: Colors.white),
),
)
],
),
);
} else {
return const SizedBox(
height: 50,
);
}
},
)
],
),
),
),
),
),
),
// Fab Buton visible olacak doldurulması geren herşey dolduğunda gözükecek
floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
floatingActionButton: FloatingActionButton(
child: const Icon(Icons.add),
onPressed: () {
// bool kontrolSonucu = aracEkleKey.currentState!.validate();
},
),
);
}
Widget buildTov(TypeOfVehicleModel typeOfVehicleModel) => ListTile(
onTap: () {
setState(() {
_collapse();
vasitaTipi = typeOfVehicleModel.typeOfVehicle;
});
if (kDebugMode) {
print("$vasitaTipi");
}
},
leading: const Icon(
Icons.stars_outlined,
size: 10,
),
title: Text(typeOfVehicleModel.typeOfVehicle.toString()),
); //Araç vasıta tipi
Widget buildBodyType(VehicleBodyTypeModel vehicleBodyTypeModel) => ListTile(
onTap: () {
setState(() {
_collapse();
kasaTipi = vehicleBodyTypeModel.vehicleBodyType;
});
if (kDebugMode) {
print(vehicleBodyTypeModel.vehicleBodyType);
}
},
leading: const Icon(
Icons.stars_outlined,
size: 10,
),
title: Text(vehicleBodyTypeModel.vehicleBodyType.toString()),
); // Araç kasa tipi
Widget buildTradeMark(TradeMarkModel tradeMarkModel) => ListTile(
onTap: () {
setState(() {
_collapse();
marka = tradeMarkModel.tradeMarkName;
});
if (kDebugMode) {
print(tradeMarkModel.tradeMarkName);
}
},
leading: const Icon(
Icons.stars_outlined,
size: 10,
),
title: Text(tradeMarkModel.tradeMarkName.toString()),
); // Araç MArka
Widget buildModel(VehicleModel vehicleModel) => ListTile(
onTap: () {
setState(() {
_collapse();
model = vehicleModel.modelName;
});
if (kDebugMode) {
print(vehicleModel.modelName);
}
},
leading: const Icon(
Icons.stars_outlined,
size: 10,
),
title: Text(vehicleModel.modelName.toString()),
); // Araç Modeli
Widget buildYear(VehicleYearModel vehicleYearModel) => ListTile(
onTap: () {
setState(() {
_collapse();
yil = vehicleYearModel.year;
});
if (kDebugMode) {
print(vehicleYearModel.year);
}
},
leading: const Icon(
Icons.stars_outlined,
size: 10,
),
title: Text(vehicleYearModel.year.toString()),
); // Araç Yılı
Widget buildProgress() => StreamBuilder<TaskSnapshot>(
stream: uploadTask?.snapshotEvents,
builder: (context, snapshot) {
if (snapshot.hasData) {
final data = snapshot.data!;
double progress = data.bytesTransferred / data.totalBytes;
return SizedBox(
height: 50,
child: Stack(
fit: StackFit.expand,
children: [
LinearProgressIndicator(
value: progress,
color: Colors.green,
backgroundColor: Colors.grey,
),
Center(
child: Text(
'${(100 * progress).roundToDouble()} %',
style: const TextStyle(color: Colors.white),
),
)
],
),
);
} else {
return const SizedBox(
height: 50,
);
}
},
);
}
I don't know which variable is causing the problem. I'm inexperienced in flutter.

Answer 1

The error message says on which line the error is. See
That means it's on line 297. If I'm not mistaken that is the line:
child: Image.file(File(pickedFile!.path!),
So pickedFile is null