Error: Field '_image' should be initialized because its type 'File' doesn't allow null.
'File' is from 'dart:io'.
File _image;
^^^^^^
code:
child: _image != null ? null : Image.file(_image,fit: BoxFit.fill,),
Check this code,you need to use setState in image selection function to update the view or show the image
class _MyHomePageState extends State<MyHomePage> {
File? _image;
final picker = ImagePicker();
Future getImage() async {
final pickedFile = await picker.getImage(source: ImageSource.gallery);
setState(() {
if (pickedFile != null) {
_image = File(pickedFile.path);
} else {
print('No image selected.');
}
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Image Picker Example'),
),
body: Center(
child: _image == null
? Text('No image selected.')
: Image.file(_image!),
),
floatingActionButton: FloatingActionButton(
onPressed: getImage,
tooltip: 'Pick Image',
child: Icon(Icons.add_a_photo),
),
);
}
}
You must initialize _image using File _image; Then inside setState use _image = File(pickedFile.path); pickedFile is return from ImagePicker. Please send full code for more customized answer
Related
I am using version 0.6.7+22 of the image_picker Flutter package to pick an image from the device in my Flutter web app. I call getImage function in a pop-up:
class _ImageVerificationPopUpState extends State<ImageVerificationPopUp> {
File _image;
final picker = ImagePicker();
#override
Widget build(BuildContext context) {
return AlertDialog(
title: Text("Upload screenshot"),
content: SizedBox(
width: MediaQuery.of(context).size.width * 0.3,
child: Center(
child: _image != null
? SelectedImage(kIsWeb ? Image.network(_image.path) : Image.file(_image), () {
setState(() {
_image = null;
});
})
: SelectImageButton(_getImage),
),
),
actions: [
TextButton(onPressed: () => Navigator.of(context).pop(), child: Text("Cancel")),
TextButton(
onPressed: () {
final ImageCubit imageCubit = BlocProvider.of<imageCubit>(context);
imageCubit.uploadImage(_image);
Navigator.pop(context);
},
child: Text("Upload"))
],
backgroundColor: Color(0xFF333D81),
);
}
Future<void> _getImage() async {
final PickedFile pickedFile = await picker.getImage(source: ImageSource.gallery);
setState(() {
if (pickedFile != null) {
_image = File(pickedFile.path);
} else {
print("No image selected");
}
});
}
}
After I press the button, it throws the following error:
Error: MissingPluginException(No implementation found for method pickImage on channel plugins.flutter.io/image_picker)
at Object.throw_ [as throw] (http://localhost:7357/dart_sdk.js:5331:11)
at platform_channel.MethodChannel.new._invokeMethod (http://localhost:7357/packages/flutter/src/services/system_channels.dart.lib.js:954:21)
at _invokeMethod.next (<anonymous>)
at http://localhost:7357/dart_sdk.js:39029:33
at _RootZone.runUnary (http://localhost:7357/dart_sdk.js:38886:58)
at _FutureListener.thenAwait.handleValue (http://localhost:7357/dart_sdk.js:33872:29)
at handleValueCallback (http://localhost:7357/dart_sdk.js:34432:49)
at Function._propagateToListeners (http://localhost:7357/dart_sdk.js:34470:17)
at _Future.new.[_completeWithValue] (http://localhost:7357/dart_sdk.js:34312:23)
at async._AsyncCallbackEntry.new.callback (http://localhost:7357/dart_sdk.js:34335:35)
at Object._microtaskLoop (http://localhost:7357/dart_sdk.js:39173:13)
at _startMicrotaskLoop (http://localhost:7357/dart_sdk.js:39179:13)
at http://localhost:7357/dart_sdk.js:34686:9
I already tried calling flutter clean, flutter pub get and rerunning my app, but it didn't help.
How can I solve this issue?
Thanks for your help in advance!
Try adding the package image_picker_for_web to your pubspec.yaml file.
...
dependencies:
...
image_picker: ^0.6.7
image_picker_for_web: ^0.1.0
...
...
then modify your _getImage method:
Future<void> _getImage() async {
final PickedFile pickedFile = await picker.getImage(source: ImageSource.gallery);
setState(() {
if (pickedFile != null) {
if (kIsWeb) { // Check if this is a browser session
_image = Image.network(pickedFile.path);
} else {
_image = Image.file(File(pickedFile.path));
}
} else {
print("No image selected");
}
});
}
I think this is what made it work for me. I was getting the same error message as you.
I have this following Flutter / dart code which let me open the camera / gallery to select a picture. But i don't want to show the image immediately on the screen (as it is here). I want the Image to deal with it, so saving it maybe or getting the image like 'Image.asset("")'. Main thing i can do something with the image after choosing it.
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
Future<File> imageFile;
pickImageFromGallery(ImageSource source) {
setState(() {
});
imageFile = ImagePicker.pickImage(source: source);
}
Widget showImage() {
return FutureBuilder<File>(
future: imageFile,
builder: (BuildContext context, AsyncSnapshot<File> snapshot) {
if (snapshot.connectionState == ConnectionState.done && snapshot.data != null) {
return Image.file(
snapshot.data,
width: 300,
height: 300,
);
}
else {
return Text("error");
}
},
);
}
bildmachen(ImageSource quelle) {
pickImageFromGallery(quelle);
Widget bildAusgabe = showImage();
Navigator.of(context).push(MaterialPageRoute(
builder: (BuildContext context) => Bildzeige(bildAusgabe)));
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
showImage,
RaisedButton(
child: Text("gehtschon?"),
onPressed: () {
bildmachen(ImageSource.gallery);
},
),
],
),
),
backgroundColor: Colors.yellowAccent,
);
}
}
Thanks
If you want to save the selected image from the ImagePicker in a File object
you may do it like this
File _imageFile;
final picker = ImagePicker();
.
.
.
Future getImage() async {
final pickedFile = await picker.getImage(source: ImageSource.gallery);
setState(() {
if (pickedFile != null) {
_imageFile = File(pickedFile.path);
}
});
}
// the getImage() method will opens the ImagePicker and the selected image will be stored in _imageFile
I hope this solution helps
I'm need to load a image from sharedPreferences to a pdf document.
The image loads normally when in normal use, but i don't know how to make it load in the pdf.
When I try to load it like a normal image I get "Unhandled Exception: type 'Image' is not a subtype of type 'PdfImage'"
This is how I use it normally.
import 'package:flutter/material.dart';
import 'package:flutter_settings_screens/flutter_settings_screens.dart';
import 'package:image_picker/image_picker.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:MyApp/SharedPrefUtility.dart';
Future<void> initSettings() async {
await Settings.init(
cacheProvider: SharePreferenceCache(),
);
}
class ProfilePage extends StatefulWidget {
#override
_ProfilePageState createState() => _ProfilePageState();
}
class _ProfilePageState extends State<ProfilePage> {
Image logo;
pickImage(ImageSource source) async {
final _image = await ImagePicker.pickImage(source: ImageSource.gallery);
if (_image != null) {
setState(() {
logo = Image.file(_image);
});
ImageSharedPrefs.saveImageToPrefs(
ImageSharedPrefs.base64String(_image.readAsBytesSync()));
} else {
print('Error picking image!');
}
}
loadImageFromPrefs() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
final imageKeyValue = prefs.getString(IMAGE_KEY);
if (imageKeyValue != null) {
final imageString = await ImageSharedPrefs.loadImageFromPrefs();
setState(() {
logo = ImageSharedPrefs.imageFrom64BaseString(imageString);
});
}
}
#override
void initState() {
super.initState();
loadImageFromPrefs();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.red,
title: Text('Profile Settings'),
),
body: Center(
child: ListView(
children: [
Column(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
ClipRect(
child: Container(
width: 300,
height: 300,
child: logo == null ? Text('No image selected.') : logo,
),
),
RaisedButton(
onPressed: () {
pickImage(ImageSource.gallery);
},
child: Text('Pick Company Logo'),
),
],
),
],
),
),
);
}
}
With SharedPrefUtility.dart
import 'dart:convert';
import 'dart:typed_data';
import 'package:flutter/widgets.dart';
import 'package:shared_preferences/shared_preferences.dart';
const IMAGE_KEY = 'IMAGE_KEY';
class ImageSharedPrefs {
static Future<bool> saveImageToPrefs(String value) async {
SharedPreferences prefs = await SharedPreferences.getInstance();
return await prefs.setString(IMAGE_KEY, value);
}
static Future<String> loadImageFromPrefs() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
return prefs.getString(IMAGE_KEY);
}
static String base64String(Uint8List data) {
return base64Encode(data);
}
static imageFrom64BaseString(String base64String) {
return Image.memory(
base64Decode(base64String),
fit: BoxFit.contain,
);
}
}
Any Suggestions would be great.
davey06 gave the answer on gitHub
final imageString = await ImageSharedPrefs.loadImageFromPrefs();
// Create a PDF document.
final document = pw.Document();
// Add page to the PDF
document.addPage(pw.Page(build: (context) {
return pw.Center(
child: pw.Image(
PdfImage.file(document.document, bytes: base64Decode(imageString)),
),
);
}));
// Return the PDF file content
return document.save();
https://github.com/DavBfr/dart_pdf/issues/477
"Unhandled Exception: type 'Image' is not a subtype of type 'PdfImage'" - it says you need to convert Image to PdfImage
import 'package:pdf/pdf.dart';
import 'package:pdf/widgets.dart ' as pw;
pdf = pw.Document();
PdfImage pdfImage = PdfImage.fromImage(pdf.document, image: logo);
pdf.addPage(
pw.Page(
pageFormat: PdfPageFormat.a4,
build: (context) {
return pw.Image(arcPdfImage, fit: pw.BoxFit.contain);
},
),
);
I'm using images taken from my assets to create PDF in this way:
PdfImage _logo = PdfImage.file(
doc.document,
bytes: (await rootBundle.load('assets/client-logo.png')).buffer.asUint8List(),
);
//later, during widget tree creation
pw.Image(_logo, width: 180);
It's not exactly what you're doing, but I think it's close enough. The PdfImage class can take as input any Uint8List for the bytes argument, so you should be able to use the same input you're using for the base64String method you defined for ImageSharedPrefs
I am trying to learn provider in flutter. But I am facing a problem. I want to get File _image from ChangeNotifier But it's showing me error.
Here is ChangeNotifierProvider
class ImagePicker extends ChangeNotifier {
File _image;
final picker = ImagePicker();
Future getImage({ImageSource source}) async {
final pickedFile = await picker.getImage(source: ImageSource.gallery);
if (pickedFile != null) {
_image = File(pickedFile.path);
} else {
print('No image selected.');
}
notifyListeners();
}
}
and here is HomeScreen where I want to get that _image file.
class HomePage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Hello"),
),
body: Container(
child: Column(
children: [
Text("Select a image"),
Image.file(Provider.of<ImagePicker>(context)._image),
IconButton(
icon: Icon(Icons.camera),
onPressed: () {
Provider.of<ImagePicker>(context).getImage();
})
],
),
),
);
}
}
It's showing me - The getter '_image' isn't defined for the type 'ImagePicker'.
Try importing the library that defines '_image', correcting the name to the name of an existing getter, or defining a getter or field named '_image'.
Please some help me for fix this error. And explain what's happening.
Change File _image variable to File image since _image means is a private variable.
Something like this:
class ImagePicker extends ChangeNotifier {
File image;
final picker = ImagePicker();
Future getImage({ImageSource source}) async {
final pickedFile = await picker.getImage(source: ImageSource.gallery);
if (pickedFile != null) {
this.image = File(pickedFile.path);
} else {
print('No image selected.');
}
notifyListeners();
}}
So as discussed in the comments, any variable underscore prefix means this variable is private. So you have two solutions :
Delete underscore from _image and the variable will be accessible from outside the class.
Define getter that return _image value.
Ohh, I solved this change _image to image.
thanks #ikerfah
I want to Pick a image and then display the picked Image. So I tried doing this->
class ImageUploadChoice extends StatefulWidget {
#override
_ImageUploadChoiceState createState() => _ImageUploadChoiceState();
}
class _ImageUploadChoiceState extends State<ImageUploadChoice> {
File imageFile;
Future getImage(int type) async {
PickedFile pickedImage = await ImagePicker().getImage(
source: type == 1 ? ImageSource.camera : ImageSource.gallery,
imageQuality: 50
);
return pickedImage;
}
For Displaying Image
Expanded(
child: Container(
child: imageFile != null
? Image.file(
imageFile,
height: MediaQuery.of(context).size.height / 5,
)
: Text("Pick up the image"),
),
),
For Calling Function->
new ListTile(
leading: new Icon(
Icons.photo_library,
color: Colors.black,),
title: new Text(
'Photo Library',
style: getTextStyle(MediaQuery.of(context).size.height, "heading2"),
),
onTap: () async {
final tmpFile = await getImage(2);
setState(() {
imageFile = tmpFile;
});
Navigator.pop(context);
Navigator.of(context).pop();
}),
But It's not Working. The Selected Image is not been displayed. What else I need to do?
Made a sample code and it's working fine. Remove following lines
Navigator.pop(context);
Navigator.of(context).pop();
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Test(),
);
}
}
class Test extends StatefulWidget {
#override
_Test createState() => _Test();
}
class _Test extends State<Test> {
File imageFile;
Future getImage() async {
final pickedFile = await ImagePicker().getImage(source: ImageSource.gallery);
setState(() {
if (pickedFile != null) {
imageFile = File(pickedFile.path);
} else {
print('No image selected.');
}
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
floatingActionButton: InkWell(
onTap: (){
getImage();
},
child: Icon(
Icons.add
),
),
body: Center(
child: root(),
),
);
}
Widget root() {
return Container(
child: imageFile != null
? Image.file(
imageFile,
height: MediaQuery
.of(context)
.size
.height / 5,
)
: Text("Pick up the image"),
);
}
}