Error : Failed to detect image file format using the file header. File header was [0x3c 0x68 0x74 0x6d 0x6c 0x3e 0x0a 0x20 0x20 0x20] - flutter

Question

I'm trying to display an image from Firestore in to my UI. But it returns the error above, and the file format also changes when I run it on Edge (not on physical device or Emulator). I can't figure out how. Here's my code.
class ViewPola extends StatefulWidget {
const ViewPola({Key? key}) : super(key: key);
static String id = 'view_pola';
#override
State<ViewPola> createState() => _ViewPolaState();
}
class _ViewPolaState extends State<ViewPola> {
Function getSnaps = () async {
final polaMap = {
'Kode Pola': '',
'Bagian Pola': '',
'image_url': '',
};
FirebaseFirestore.instance
.collection('PolaWillyJKT')
.limit(1)
.get()
.then((snapshot) {
if (snapshot.size == 0) {
FirebaseFirestore.instance.collection('PolaWillyJKT').add(polaMap);
FirebaseFirestore.instance.collection('PolaWillyJKT');
print('add');
} else {
print('disini nge get');
var a = FirebaseFirestore.instance.collection('PolaWillyJKT').get();
Map<String, dynamic> data = a as Map<String, dynamic>;
print(data);
}
});
};
var _selectedItem;
var _showList = false;
#override
void initState() {
getSnaps();
super.initState();
}
final Stream<QuerySnapshot> _polaWilly =
FirebaseFirestore.instance.collection('PolaWillyJKT').snapshots();
#override
Widget build(BuildContext context) {
final screenHeight = ScreenInfo.screenHeight(context);
final screenWidth = ScreenInfo.screenWidth(context);
return StreamBuilder<QuerySnapshot>(
stream: _polaWilly,
builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
if (snapshot.hasError) {
return Text('Something went wrong');
}
if (snapshot.connectionState == ConnectionState.waiting) {
return Text("Loading");
}
return SafeArea(
child: Scaffold(
body: Padding(
padding: EdgeInsets.all(25),
child: Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
const Text(
'Pilih Bagian Pola',
style: TextStyle(fontSize: 25),
),
const SizedBox(
height: 20,
),
DropdownButton(
isExpanded: true,
value: _selectedItem,
items: snapshot.data?.docs
.map(
(value) => DropdownMenuItem(
value: value.get("Bagian Pola"),
child: Text('${value.get("Bagian Pola")}'),
),
)
.toList(),
onChanged: (newValue) {
setState(() {
_selectedItem = newValue.toString();
_showList = true;
});
}),
Padding(
padding: const EdgeInsets.all(25),
child: Visibility(
visible: _showList,
child: Container(
height: screenHeight * 0.4,
child: ListView(
children: snapshot.data!.docs
.where(
(e) => e.get("Bagian Pola") == _selectedItem)
.map((DocumentSnapshot document) {
Map<String, dynamic> data =
document.data()! as Map<String, dynamic>;
return Center(
child: Column(
children: [
Text(
'Bagian Pola: ${data["Bagian Pola"]}',
style: TextStyle(fontSize: 15),
),
const SizedBox(
height: 15,
),
Text(
'Kode Pola : ${data["Kode Pola"]}',
style: TextStyle(fontSize: 15),
),
const SizedBox(
height: 15,
),
Image(
image:
NetworkImage(document.get("Foto Pola")),
height: 200,
width: 200,
), // this is the Image widget where I tried to put the image from firestore
Text(document.get('Foto Pola').toString()),
],
),
);
}).toList(),
),
),
),
),
],
),
),
),
);
},
);
}
}
and here's the class that uploads the image to Firestore
class Input_Pola extends StatefulWidget {
const Input_Pola({Key? key}) : super(key: key);
static String id = 'input_pola';
#override
State<Input_Pola> createState() => _Input_PolaState();
}
class _Input_PolaState extends State<Input_Pola> {
final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
void _checkDuplicate() {
if (options.contains(_textfieldValue.text)) {
// Display bottom sheet that says item already exists
_scaffoldKey.currentState?.showBottomSheet((context) => Container(
height: 300,
child: Column(
children: [
const Text('Item already exists'),
TextButton(
onPressed: () {
Navigator.pop(context);
},
child: Text('Dismiss'))
],
),
));
} else {
// Add item to options list
setState(() {
options.add(_textfieldValue.text);
});
}
}
XFile? image;
final ImagePicker picker = ImagePicker();
String _image_url = '';
void _addToFirebase(String dropdownValue, String _kodePolaController) {
var imageFile = File(image!.path);
String fileName = pth.basename(imageFile.path);
FirebaseStorage storage = FirebaseStorage.instance;
Reference ref = storage.ref().child("WillyJKT/polaWillyJKT");
UploadTask uploadTask = ref.putFile(imageFile);
uploadTask.whenComplete(() async {
var url = await ref.getDownloadURL();
_image_url = url.toString();
});
FirebaseFirestore.instance
.collection('PolaWillyJKT')
.doc(_selectedOption)
.set({
'Bagian Pola': _selectedOption,
'Kode Pola': _kodePolaController,
'Foto Pola': _image_url
});
}
String _dropdownValue = 'kg';
String _property1 = '';
String _property2 = '';
String _property3 = '';
bool _isOptionSelected = false;
final TextEditingController _kodePolaController = TextEditingController();
var _selectedOption;
final TextEditingController _textfieldValue = TextEditingController();
final List<String> options = [];
#override
void initState() {
super.initState();
_selectedOption = options.isNotEmpty ? options[0] : null;
}
//we can upload image from camera or from gallery based on parameter
Future getImage(ImageSource media) async {
var img = await picker.pickImage(source: media);
setState(() {
image = img;
});
}
void myAlert() {
showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
shape:
RoundedRectangleBorder(borderRadius: BorderRadius.circular(8)),
title: Text('Please choose media to select'),
content: Container(
height: MediaQuery.of(context).size.height / 6,
child: Column(
children: [
ElevatedButton(
//if user click this button, user can upload image from gallery
onPressed: () {
Navigator.pop(context);
getImage(ImageSource.gallery);
},
child: Row(
children: [
Icon(Icons.image),
Text('From Gallery'),
],
),
),
ElevatedButton(
//if user click this button. user can upload image from camera
onPressed: () {
Navigator.pop(context);
getImage(ImageSource.camera);
},
child: Row(
children: [
Icon(Icons.camera),
Text('From Camera'),
],
),
),
],
),
),
);
});
}
#override
Widget build(BuildContext context) {
final screenHeight = ScreenInfo.screenHeight(context);
final screenWidth = ScreenInfo.screenWidth(context);
return SafeArea(
child: Scaffold(
key: _scaffoldKey,
floatingActionButton: FloatingActionButton(
child: const Icon(Icons.add),
onPressed: () {
_addToFirebase(_dropdownValue, _kodePolaController.text);
},
),
body: SingleChildScrollView(
child: Padding(
padding: const EdgeInsets.all(25),
child: Container(
height: screenHeight,
child: Column(
mainAxisAlignment: MainAxisAlignment.start,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
TextFormField(
decoration: const InputDecoration(
hintText: 'Input Pola',
border: UnderlineInputBorder(),
),
onChanged: (value) {
setState(() {
_textfieldValue.text = value;
});
},
),
DropdownButton<String>(
value: _selectedOption,
onChanged: (value) {
setState(() {
_selectedOption = value!;
_isOptionSelected = true;
_kodePolaController.clear();
});
},
hint: const Text('Input from Text Field Above'),
items: options.map((option) {
return DropdownMenuItem<String>(
value: option,
child: Text(option),
);
}).toList(),
),
TextButton(
onPressed: _checkDuplicate,
child: const Text("Add Option"),
),
Visibility(
visible: _isOptionSelected,
child: Expanded(
child: Column(
mainAxisAlignment: MainAxisAlignment.start,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
TextField(
controller: _kodePolaController,
decoration: const InputDecoration(
labelText: "Kode Pola"),
onChanged: (value) {
setState(() {
_property1 = value;
});
},
),
const SizedBox(height: 20,),
ElevatedButton(
onPressed: () {
myAlert();
},
child: Text('Upload Photo'),
),
SizedBox(
height: 10,
),
//if image not null show the image
//if image null show text
image != null
? Padding(
padding:
const EdgeInsets.symmetric(horizontal: 20),
child: ClipRRect(
borderRadius: BorderRadius.circular(8),
child: Image.file(
//to show image, you type like this.
File(image!.path),
fit: BoxFit.cover,
width: MediaQuery.of(context).size.width,
height: 300,
),
),
)
: const Text(
"No Image",
style: TextStyle(fontSize: 20),
),
],
),
),
)
],
),
),
),
),
),
);
}
}
It also displays the error on Edge, but when I build the apk and run it on my physical device, it just shows nothing on the screen except for the data that's got above it. Any idea on how I can fix this?

Answer 1

var a = FirebaseFirestore.instance.collection('PolaWillyJKT').get();
This returns a promise but not the actual data. In fact it could still be fetching the data when you attempt to convert it to a map.
You can await
var a = await FirebaseFirestore.instance.collection('PolaWillyJKT').get();
myDoc = a.docs.first();
Or use a callback that will run once the collection fetch completes:
FirebaseFirestore.instance.collection('PolaWillyJKT').get().then((response) => {
print(response);
});