Reading an image file from device storage and converting to Base64 results in an invalid base64 in Flutter
2,626
print function did not print everything.
you can see full result with debug mode
code snippet
List<int> imageBytes = await _imageFile.readAsBytes();
String base64Image = base64Encode(imageBytes);
print(base64Image);
Copy base64 string from debug mode and paste to online converter, you can see result is correct.
full code from offical demo and add base64 convert
// Copyright 2019 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:async';
import 'dart:io';
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
import 'package:video_player/video_player.dart';
import 'dart:typed_data';
import 'package:image/image.dart' as ImageProcess;
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Image Picker Demo',
home: MyHomePage(title: 'Image Picker Example'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
File _imageFile;
dynamic _pickImageError;
bool isVideo = false;
VideoPlayerController _controller;
String _retrieveDataError;
Future<void> _playVideo(File file) async {
if (file != null && mounted) {
await _disposeVideoController();
_controller = VideoPlayerController.file(file);
await _controller.setVolume(1.0);
await _controller.initialize();
await _controller.setLooping(true);
await _controller.play();
setState(() {});
}
}
void _onImageButtonPressed(ImageSource source) async {
if (_controller != null) {
await _controller.setVolume(0.0);
}
if (isVideo) {
final File file = await ImagePicker.pickVideo(source: source);
await _playVideo(file);
} else {
try {
_imageFile = await ImagePicker.pickImage(source: source);
List<int> imageBytes = await _imageFile.readAsBytes();
String base64Image = base64Encode(imageBytes);
print(base64Image);
setState(() {});
} catch (e) {
_pickImageError = e;
}
}
}
@override
void deactivate() {
if (_controller != null) {
_controller.setVolume(0.0);
_controller.pause();
}
super.deactivate();
}
@override
void dispose() {
_disposeVideoController();
super.dispose();
}
Future<void> _disposeVideoController() async {
if (_controller != null) {
await _controller.dispose();
_controller = null;
}
}
Widget _previewVideo() {
final Text retrieveError = _getRetrieveErrorWidget();
if (retrieveError != null) {
return retrieveError;
}
if (_controller == null) {
return const Text(
'You have not yet picked a video',
textAlign: TextAlign.center,
);
}
return Padding(
padding: const EdgeInsets.all(10.0),
child: AspectRatioVideo(_controller),
);
}
Widget _previewImage() {
final Text retrieveError = _getRetrieveErrorWidget();
if (retrieveError != null) {
return retrieveError;
}
if (_imageFile != null) {
return Image.file(_imageFile);
} else if (_pickImageError != null) {
return Text(
'Pick image error: $_pickImageError',
textAlign: TextAlign.center,
);
} else {
return const Text(
'You have not yet picked an image.',
textAlign: TextAlign.center,
);
}
}
Future<void> retrieveLostData() async {
final LostDataResponse response = await ImagePicker.retrieveLostData();
if (response.isEmpty) {
return;
}
if (response.file != null) {
if (response.type == RetrieveType.video) {
isVideo = true;
await _playVideo(response.file);
} else {
isVideo = false;
setState(() {
_imageFile = response.file;
});
}
} else {
_retrieveDataError = response.exception.code;
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Platform.isAndroid
? FutureBuilder<void>(
future: retrieveLostData(),
builder: (BuildContext context, AsyncSnapshot<void> snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.none:
case ConnectionState.waiting:
return const Text(
'You have not yet picked an image.',
textAlign: TextAlign.center,
);
case ConnectionState.done:
return isVideo ? _previewVideo() : _previewImage();
default:
if (snapshot.hasError) {
return Text(
'Pick image/video error: ${snapshot.error}}',
textAlign: TextAlign.center,
);
} else {
return const Text(
'You have not yet picked an image.',
textAlign: TextAlign.center,
);
}
}
},
)
: (isVideo ? _previewVideo() : _previewImage()),
),
floatingActionButton: Column(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
FloatingActionButton(
onPressed: () {
isVideo = false;
_onImageButtonPressed(ImageSource.gallery);
},
heroTag: 'image0',
tooltip: 'Pick Image from gallery',
child: const Icon(Icons.photo_library),
),
Padding(
padding: const EdgeInsets.only(top: 16.0),
child: FloatingActionButton(
onPressed: () {
isVideo = false;
_onImageButtonPressed(ImageSource.camera);
},
heroTag: 'image1',
tooltip: 'Take a Photo',
child: const Icon(Icons.camera_alt),
),
),
Padding(
padding: const EdgeInsets.only(top: 16.0),
child: FloatingActionButton(
backgroundColor: Colors.red,
onPressed: () {
isVideo = true;
_onImageButtonPressed(ImageSource.gallery);
},
heroTag: 'video0',
tooltip: 'Pick Video from gallery',
child: const Icon(Icons.video_library),
),
),
Padding(
padding: const EdgeInsets.only(top: 16.0),
child: FloatingActionButton(
backgroundColor: Colors.red,
onPressed: () {
isVideo = true;
_onImageButtonPressed(ImageSource.camera);
},
heroTag: 'video1',
tooltip: 'Take a Video',
child: const Icon(Icons.videocam),
),
),
],
),
);
}
Text _getRetrieveErrorWidget() {
if (_retrieveDataError != null) {
final Text result = Text(_retrieveDataError);
_retrieveDataError = null;
return result;
}
return null;
}
}
class AspectRatioVideo extends StatefulWidget {
AspectRatioVideo(this.controller);
final VideoPlayerController controller;
@override
AspectRatioVideoState createState() => AspectRatioVideoState();
}
class AspectRatioVideoState extends State<AspectRatioVideo> {
VideoPlayerController get controller => widget.controller;
bool initialized = false;
void _onVideoControllerUpdate() {
if (!mounted) {
return;
}
if (initialized != controller.value.initialized) {
initialized = controller.value.initialized;
setState(() {});
}
}
@override
void initState() {
super.initState();
controller.addListener(_onVideoControllerUpdate);
}
@override
void dispose() {
controller.removeListener(_onVideoControllerUpdate);
super.dispose();
}
@override
Widget build(BuildContext context) {
if (initialized) {
return Center(
child: AspectRatio(
aspectRatio: controller.value?.aspectRatio,
child: VideoPlayer(controller),
),
);
} else {
return Container();
}
}
}
Comments
-
sachq over 1 year
I'm trying to read file from a known path get base64 string from the image. I still don't understand why
base64
is broken. This happens only in flutter code.I did try doing the same conversion using a simple dart program i got the desired
base64
string. This issue is happening in flutter.onPressed: () async { File imageFile = await ImagePicker.pickImage(source: ImageSource.camera); if (imageFile != null) { Uint8List bytes = await imageFile.readAsBytes(); String base64data = base64.encode(bytes); print(base64data); } }
Following is my console output.
W/ExifInterface(15331): Skip the tag entry since tag number is not defined: 2 W/ExifInterface(15331): Stop reading file since a wrong offset may cause an infinite loop: 0 I/chatty (15331): uid=10271(com.crowdanalytix.datax_app) Binder:15331_5 identical 2 lines W/ExifInterface(15331): Stop reading file since a wrong offset may cause an infinite loop: 0 I/flutter (15331): 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
Base64
string which i'm getting is invalid. Can someone try this?I'm using a
OnePlus3t (ONEPLUS A3003)
.-
pskink over 4 yearstry this:
imageFile.openRead() .transform(base64.encoder) .listen(debugPrint);
- do you see the right base64 now? -
sachq over 4 yearsYou've only told me this answer. Print function doesn't put everything to console apparently.
-
pskink over 4 yearsi have no idea what you mean by that, just add the above code inside
if (imageFile != null) {
and remove your 3 lines from it -
sachq over 4 yearsCheck the below answer. Base64 is a very long string, it doesn't print everything to the console.
-
sachq over 4 yearsnot really. Getting same as print.
-
sachq over 4 yearsCheck the accepted answer. Base64 is long string it doesn't print it and i checked in debug mode it has the base64 string in whole, What really confused me here was because of the custom API which i was using, which was returning invalid image data (in fact it was customized for a certain set of images only). Just clarified with my backend team. Facepalm
-