[英]how to convert an image to base64 image in flutter?
I am actually trying to convert an image picked by ImagePicker
in flutter to base64
image.我实际上正在尝试将ImagePicker
在 flutter 中选择的图像转换为base64
图像。 I am always getting the error.我总是收到错误。
FileSystemException: Cannot open file, path =
'file:///storage/emulated/0/Download/Abid_Wipro_neemuchwala1-
770x433.jpg' (OS Error: No such file or directory, errno = 2)
E/flutter ( 5042): #0 _File.throwIfError
(dart:io/file_impl.dart:628)
E/flutter ( 5042): #1 _File.openSync
(dart:io/file_impl.dart:472)
E/flutter ( 5042): #2 _File.readAsBytesSync
(dart:io/file_impl.dart:532)
the code i am using is this one.我正在使用的代码是这个。
File fileData;
/////////////...........
new Container(
child: new FutureBuilder<File>(
future: imageFile,
builder: (BuildContext context, AsyncSnapshot<File> snapshot) {
if (snapshot.connectionState == ConnectionState.done &&
snapshot.data != null) {
fileData = snapshot.data;
return new Container(
height: MediaQuery.of(context).size.height / 2,
width: MediaQuery.of(context).size.width,
margin: const EdgeInsets.all(4.0),
decoration: new BoxDecoration(
image: new DecorationImage(
image: new FileImage(snapshot.data,),
fit: BoxFit.cover
),
),
);
} else if (snapshot.error != null) {
return new Column(children: <Widget>[
centerWidget('Choose Image or Audio or Video'),
_circleAvatar()
]);
} else {
return new Column(children: <Widget>[
centerWidget('Choose Image or Audio or Video'),
_circleAvatar()
]);
}
},
),
),
/////////////////
File imageFile = new File(widget.fileData.uri.toString());
List<int> imageBytes = imageFile.readAsBytesSync();
String base64Image = base64Encode(imageBytes);
Please, can someone tell me where is it that i am making a mistake.拜托,有人能告诉我我在哪里犯了错误吗?
Many thanks, Mahi非常感谢, Mahi
I just changed my code as follows,我只是改变了我的代码如下,
import 'dart:convert';
List<int> imageBytes = widget.fileData.readAsBytesSync();
print(imageBytes);
String base64Image = base64Encode(imageBytes);
and this is working fine now.这现在工作正常。
It is better to read it asynchronously as the image can be very large which may cause blocking of the main thread最好异步读取,因为图像可能非常大,可能会导致主线程阻塞
List<int> imageBytes = await widget.fileData.readAsBytes();
you can simply change the image to string :您可以简单地将图像更改为字符串:
final bytes = Io.File(imageBytes.path).readAsBytesSync();
String img64 = base64Encode(bytes);
In my case, i first selected the image using image_picker then use these line of code to convert the image to base64.就我而言,我首先使用image_picker选择图像,然后使用这些代码行将图像转换为 base64。
final bytes = File(image!.path).readAsBytesSync();
String base64Image = "data:image/png;base64,"+base64Encode(bytes);
print("img_pan : $base64Image");
image_picker code: image_picker 代码:
final ImagePicker _picker = ImagePicker();
XFile? image;
Container(
margin: const EdgeInsets.all(15.0),
padding: const EdgeInsets.all(3.0),
decoration: BoxDecoration(
border: Border.all(color: Colors.black),
borderRadius: BorderRadius.all(Radius.circular(5.h))
),
child:InkWell(
onTap: () async {
image = await _picker.pickImage(
source: ImageSource.gallery);
setState(() {});
},
child: image != null
? Image.file(
File(image!.path),
height: 100.h,
width: 100.w,
)
: Image.asset(
'assets/image_icon.png',
height: 100.h,
width: 100.w,
fit: BoxFit.fill,
),
),),
Container(
child: new GestureDetector(
onTap: () async {
FocusScope.of(context)
.requestFocus(new FocusNode());
await getImage();
},
child: new Center(
child: _image == null
? new Stack(
children: <Widget>[
new Center(
child: new CircleAvatar(
radius: 80.0,
backgroundColor:
const Color(0xFF778899),
),
),
new Center(
child: Icon(
Icons.perm_identity,
size: 120,
),
),
],
)
: new CircleAvatar(
radius: 60,
child: ClipOval(
child: Align(
heightFactor: 0.8,
widthFactor: 1.0,
child: new Image.file(_image),
),
),
),
),
),
),
Future getImage() async {
UserService userRestSrv = UserService();
PickedFile image = await ImagePicker().getImage(source: ImageSource.gallery, imageQuality: 50);
if (image != null) {
setState(() {
_image = File(image.path);
});
final bytes = File(image.path).readAsBytesSync();
String img64 = base64Encode(bytes);
var responseProfileImage = await userRestSrv.updateImage(userId, img64);
if (responseProfileImage != null && responseProfileImage.data['ResponseCode'] == "00")
showMessage('Profile Image not uploaded', false);
}
}
In case you are trying to manage image/file uploads using Flutter Web, https://pub.dev/packages/file_picker is a better package to go with.如果您尝试使用 Flutter Web 管理图像/文件上传, https ://pub.dev/packages/file_picker 是一个更好的软件包。
As we know, dart:io
is not supported on Flutter Web and throws Unsupported operation: _Namespace
error.众所周知,Flutter Web 不支持dart:io
并抛出Unsupported operation: _Namespace
错误。 Hence, using File
and reading file's bytes was not an option.因此,使用File
和读取文件的字节不是一种选择。 Luckily, the package provides API to convert the uploaded image to Uint8List
.幸运的是,该包提供了 API 来将上传的图像转换为Uint8List
。 Here is my implementation:这是我的实现:
import 'package:file_picker/file_picker.dart';
...
FilePickerResult? pickedFile;
...
void chooseImage() async {
pickedFile = await FilePicker.platform.pickFiles();
if (pickedFile != null) {
try {
setState(() {
logoBase64 = pickedFile!.files.first.bytes;
});
} catch (err) {
print(err);
}
} else {
print('No Image Selected');
}
}
In case you need to display the local image right away, use Image.memory
.如果您需要立即显示本地图像,请使用Image.memory
。
Image.memory(logoBase64!);
//this is dart code
final bytes = File(image!.path).readAsBytesSync();
String base64Image = base64Encode(bytes);
print("imgbytes : $base64Image");
//this is flutter code for image picker
Future uploadAll() async {
var bytes = File(image!.path).readAsBytesSync();
String base64Image = base64Encode(bytes);
print('upload proccess started');
var apipostdata = {
"title": contentController.text.toString().toUpperCase(),
"book_image": base64Image,
"book_type": _genderRadioBtnVal,
};
await http
.post(Uri.parse('http://192.168.29.111:8000/api/book/add_book'),
body: apipostdata)
.then((response) {
var returndata = jsonEncode(response.body);
if (response.statusCode == 200) {
print(returndata);
} else {
print('failed');
}
}).catchError((err) {
setState(() {
err;
});
}); }
I see that more than one has already answered the question.我看到不止一个人已经回答了这个问题。 But I allow myself to put my solution and it works for me.但我允许自己提出我的解决方案,它对我有用。 I use file_picker: ^5.0.1
我使用file_picker: ^5.0.1
void openFileImageExplorer() async {
//try {
final pickedFile = await FilePicker.platform.pickFiles(
allowedExtensions: ['jpg', 'jpeg', 'png', 'bmp', 'gif']
);
if (pickedFile == null) {
return;
}
final file = pickedFile.files.first;
final bytes = File(file.path!).readAsBytesSync();
String img64 = base64Encode(bytes);
setState(() {
imageBase64 = img64;
});
logCat(img64);
//} catch(ex, trace ){
// logError(ex, trace: trace);
//}
}
And to display the image并显示图像
Image.memory( base64Decode(imageBase64), fit: BoxFit.cover )
and I hope it will help...我希望它会有所帮助......
Here a simple function:这是一个简单的 function:
String convertIntoBase64(File file) {
List<int> imageBytes = file.readAsBytesSync();
String base64File = base64Encode(imageBytes);
return base64File;
}
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