How to convert List to List in flutter

Question

I am using this package to get mutliple images from gallery and it return a list of Asset, now I want to send it to server, I am use FormDate but there image path required.

Is there any other way to send Asset image to server?
how to convert List<Asset> to List<File>.
how to get image path from Asset

Or any other method to done this task(Choose mutliple images from storage and send them to server).

List<Asset> images = List<Asset>();

FormData imageFormData = FormData.fromMap({
  "files": images.map((image) async {
     return await MultipartFile.fromFile('assets/${image.name}', filename: image.name);
     }).toList(),
});

use [MultipartRequest](https://pub.dev/documentation/http/latest/http/MultipartRequest-class.html) — pskink, Mar 02 '20 at 07:29
@Naeem if you find out the answer, please post it below, I also using same multi-image picker library, can you? — FGH, Mar 16 '20 at 12:03

score 3 · Accepted Answer · answered Mar 25 '21 at 10:14

Here is the solution.

List<Asset> images = List<Asset>();
List<MultipartFile> multipart = List<MultipartFile>();
for (int i = 0; i < images.length; i++) {
  var path = await FlutterAbsolutePath.getAbsolutePath(images[i].identifier);
  multipart.add(await MultipartFile.fromFile(path, filename: 'myfile.jpg'));
}
FormData imageFormData = FormData.fromMap({"files": multipart,});

score 2 · Answer 2 · answered Jun 25 '20 at 11:15

Make use of flutter_absolute_path package.

add flutter_absolute_path: ^1.0.6 in pubsec.yaml

 This will convert file path from this format : “content://media/external/images/media/5275” To this format (absolute format) "/storage/emulated/0/DCIM/Camera/IMG_00124.jpg”

Then make use of this method:

Future<List> imagePicker() async{

List<Asset> assetArray = [];
List <File> fileImageArray = [];

try {
    assetArray = await MultiImagePicker.pickImages(
        maxImages: 300,
        enableCamera: true,
        selectedAssets:  assetArray ,
        cupertinoOptions: CupertinoOptions(takePhotoIcon: "chat"),
        materialOptions: MaterialOptions(
            actionBarColor: "",
            actionBarTitle: "ImagePicker",
            allViewTitle: "All Photos",
            useDetailsView: false,
            selectCircleStrokeColor: "#000000",
            ),
        );
}on Exception catch (e) {
    print( e.toString());
}

assetArray.forEach((imageAsset) async {
    final filePath = await FlutterAbsolutePath.getAbsolutePath(imageAsset.identifier);
    
    File tempFile = File(filePath);
    if (tempFile.existsSync()) {
        fileImageArray.add(tempFile);
    }
});

return fileImageArray;

}

score 1 · Answer 3 · answered Mar 02 '20 at 07:15

I think you can read assets file as file before sending over as below:

File imageFile = File('yourAssetsUriPath.jpg');

yourAssetsUriPath is pointing to your assets folder by default, so you can simply put your filename in the path.

As for http post it, you can refer here

How to convert List to List in flutter

3 Answers3