Wrong Flutter error Convert image ImagePicker type File to base64, Wrong Encoded - flutter

Question

I need to convert an image that I get from the device with ImagePicker, convert it from File type to base64 to store it through a post in a db, but the procedure I do to convert it does not do it well, it converts only a thin line and the rest blank, apparently readAsbyte does not convert well when implemented as "var bytes = imageFile.readAsBytesSync ();" makes it incomplete
this is how i am implementing it
File imageFile;
void _openGallery(BuildContext context) async{
var picture = await ImagePicker().getImage(source: ImageSource.gallery);
this.setState(() {
imageFile = File(picture.path);
var bytes = imageFile.readAsBytesSync();
String imagenConvertida = base64.encode(bytes);
print(bytes);
print(imagenConvertida);
});
Navigator.of(context).pop();
}

Answer 1

From your implementation,
File imageFile;
void _openGallery(BuildContext context) async{
var picture = await ImagePicker().getImage(source: ImageSource.gallery);
this.setState(() {
imageFile = File(picture.path);
var bytes = imageFile.readAsBytesSync();
String imagenConvertida = base64.encode(bytes);
print(bytes);
print(imagenConvertida);
});
Navigator.of(context).pop();
The output of bytes is
[255, 216, 255, 225, 1, 181, 69, 120, 105, 102, 0, 0, 77, 77, 0, 42,
0, 0, 0, 8, 0, 7, 1, 16, 0, 2, 0, 0, 0, 26, 0, 0, 0, 98, 1, 0, 0, 4,
0, 0, 0, 1, 0, 0, 3, 192, 1, 1, 0, 4, 0, 0, 0, 1, 0, 0, 5, 0, 1, 50,
0, 2, 0, 0, 0, 20, 0, 0, 0, 124, 1, 18, 0, 3, 0, 0, 0, 1, 0, 1, 0, 0,
135, 105, 0, 4, 0, 0, 0, 1, 0, 0, 0, 151, 1, 15, 0, 2, 0, 0, 0, 7, 0,
0, 0, 144, 0, 0, 0, 0, 65, 110, 100, 114, 111, 105, 100, 32, 83, 68,
75, 32, 98, 117, 105, 108, 116, 32, 102, 111, 114, 32, 120, 56, 54, 0,
50, 48, 50, 48, 58, 48, 57, 58, 48, 50, 32, 48, 52, 58, 49, 53, 58,
51, 54, 0, 71, 111, 111, 103, 108, 101, 0, 0, 16, 130, 157, 0, 5, 0,
0, 0, 1, 0, 0, 1, 93, 130, 154, 0, 5, 0, 0, 0, 1, 0, 0, 1, 101, 146,
146, 0, 2, 0, 0, 0, 4, 56, 56, 57, 0, 146, 145, 0, 2, 0, 0, 0, 4, 56,
56, 57, 0, 146, 144, 0, 2, 0, 0, 0, 4, 56, 56, 57, 0, 146, 10, 0, 5,
0, 0, 0, 1, 0, 0, 1, 109, 146, 9, 0, 3, 0, 0, 0, 1, 0, 0, 0, 0, 136,
39, 0, 3, 0, 0, 0, 1, 0, 100, 0, 0, 144, 4, 0, 2, 0, 0, 0, 20, 0, 0,
1, 117, 144, 3, 0, 2, 0, 0, 0, 20, 0,
The output of imagenConvertida is
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
Reversing it, I come up with the following code:
File imageFile;
Image decodedImage;
void _openGallery(BuildContext context) async {
var picture = await ImagePicker().getImage(source: ImageSource.gallery);
this.setState(
() {
imageFile = File(picture.path);
// Convert image to base64
var bytes = imageFile.readAsBytesSync();
String imagenConvertida = base64.encode(bytes);
print('Value of bytes: $bytes');
print('Value of imagenConvertida: $imagenConvertida');
// Convert base64 to image
Uint8List decodedBytes = base64.decode(imagenConvertida);
decodedImage = Image.memory(decodedBytes);
print('Value of decodedBytes: $decodedBytes');
print('Value of decodedImage: $decodedImage');
},
);
// Commented out for testing purposes
// Navigator.of(context).pop();
}
When you compare the output the value of decodedBytes
[255, 216, 255, 225, 1, 181, 69, 120, 105, 102, 0, 0, 77, 77, 0, 42,
0, 0, 0, 8, 0, 7, 1, 16, 0, 2, 0, 0, 0, 26, 0, 0, 0, 98, 1, 0, 0, 4,
0, 0, 0, 1, 0, 0, 3, 192, 1, 1, 0, 4, 0, 0, 0, 1, 0, 0, 5, 0, 1, 50,
0, 2, 0, 0, 0, 20, 0, 0, 0, 124, 1, 18, 0, 3, 0, 0, 0, 1, 0, 1, 0, 0,
135, 105, 0, 4, 0, 0, 0, 1, 0, 0, 0, 151, 1, 15, 0, 2, 0, 0, 0, 7, 0,
0, 0, 144, 0, 0, 0, 0, 65, 110, 100, 114, 111, 105, 100, 32, 83, 68,
75, 32, 98, 117, 105, 108, 116, 32, 102, 111, 114, 32, 120, 56, 54, 0,
50, 48, 50, 48, 58, 48, 57, 58, 48, 50, 32, 48, 52, 58, 49, 53, 58,
51, 54, 0, 71, 111, 111, 103, 108, 101, 0, 0, 16, 130, 157, 0, 5, 0,
0, 0, 1, 0, 0, 1, 93, 130, 154, 0, 5, 0, 0, 0, 1, 0, 0, 1, 101, 146,
146, 0, 2, 0, 0, 0, 4, 56, 56, 57, 0, 146, 145, 0, 2, 0, 0, 0, 4, 56,
56, 57, 0, 146, 144, 0, 2, 0, 0, 0, 4, 56, 56, 57, 0, 146, 10, 0, 5,
0, 0, 0, 1, 0, 0, 1, 109, 146, 9, 0, 3, 0, 0, 0, 1, 0, 0, 0, 0, 136,
39, 0, 3, 0, 0, 0, 1, 0, 100, 0, 0, 144, 4, 0, 2, 0, 0, 0, 20, 0, 0,
1, 117, 144, 3, 0, 2, 0, 0, 0,
And when you convert it, it will give you the exact original image, see the sample app code below:
import 'dart:convert';
import 'dart:io';
import 'dart:typed_data';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';
import 'package:image_picker/image_picker.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(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
// From SO
File imageFile;
Image decodedImage;
void _openGallery(BuildContext context) async {
var picture = await ImagePicker().getImage(source: ImageSource.gallery);
this.setState(
() {
imageFile = File(picture.path);
// Convert image to base64
var bytes = imageFile.readAsBytesSync();
String imagenConvertida = base64.encode(bytes);
print('Value of bytes: $bytes');
print('Value of imagenConvertida: $imagenConvertida');
// Convert base64 to image
Uint8List decodedBytes = base64.decode(imagenConvertida);
decodedImage = Image.memory(decodedBytes);
print('Value of decodedBytes: $decodedBytes');
print('Value of decodedImage: $decodedImage');
},
);
// Commented out for testing purposes
// Navigator.of(context).pop();
}
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
SizedBox(
height: 20.0,
),
Text('Original image from gallery'),
SizedBox(height: 10.0),
Container(
color: Colors.blueGrey,
height: 200.0,
width: 150.0,
child: imageFile == null
? Text('Image is not loaded')
: Image.file(imageFile),
),
SizedBox(height: 20.0),
Text('Image decoded from base64'),
SizedBox(height: 10.0),
Container(
color: Colors.grey,
height: 200.0,
width: 150.0,
child: decodedImage == null
? Text('Image is not loaded')
: decodedImage,
),
],
),
),
floatingActionButton: Row(
mainAxisAlignment: MainAxisAlignment.end,
// crossAxisAlignment: CrossAxisAlignment.end,
children: <Widget>[
FloatingActionButton(
onPressed: () {
// _getImage();
_openGallery(context);
print('Open Gallery');
},
tooltip: 'Pick an image',
child: Icon(Icons.image),
),
SizedBox(
width: 20,
),
],
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
Since the decoded image is the same as the original image, I think var bytes = imageFile.readAsBytesSync(); is working fine.