如何在 Flutter 中使用 Dio 和 multi_image_picker 插件上传多张图片

我想在 Flutter 中使用 Dio 和 multi_image_picker 插件上传多张图片。

List<Asset>这就是问题，因为我无法转换List<Asset> to List<File>所以如果你有任何解决方案帮助我。

尝试使用：

1. multi_image_picker: ^4.6.1

2. dio: ^3.0.4

Thanks

Bona SR.

import 'dart:io';
import 'package:dio/dio.dart';
import 'package:flutter/material.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:merchantside/helper/colorhelper.dart';
import 'package:merchantside/merchantside/login.dart';
import 'dart:async';
import 'package:multi_image_picker/multi_image_picker.dart';

class ListImages extends StatefulWidget {
  String errorMessage = "";
  @override
  _ListImagesState createState() => new _ListImagesState();
}

class _ListImagesState extends State<ListImages> {
  List<Asset> images = List<Asset>();
  List<File> listImages = [];
  @override
  void initState() {
    super.initState();
  }

  Widget buildGridView() {
    return GridView.count(
      crossAxisCount: 3,
      children: List.generate(images.length, (index) {
        Asset asset = images[index];
        return AssetThumb(
          asset: asset,
          width: 300,
          height: 300,
        );
      }),
    );
  }


  void _uploadFiles() async {
    String uid = await FlutterSecureStorage().read(key: "getTocken");
    try {
      var dio = Dio();
      FormData formData = new FormData.fromMap({
        "pictures[]": images, 
      });
      Response resp = await dio.post(
        mainUrl + 'merchant/upload-galleries',
        data: formData,
        onSendProgress: (int sent, int total) {
          //
        }, 
        options: Options(
          headers: {
            HttpHeaders.authorizationHeader: uid,
          },
        )
      );
      if(resp.statusCode == 200) {
        print("============= Print Resp data: ");
        print(resp.data);
      }

    } catch (e) {
      print(e);
    }
  }

  Future<void> loadAssets() async {
    List<Asset> resultList = List<Asset>();
    try {
      resultList = await MultiImagePicker.pickImages(
        maxImages: 6,
        enableCamera: true,
        selectedAssets: images,
        cupertinoOptions: CupertinoOptions(takePhotoIcon: "chat"),
        materialOptions: MaterialOptions(
          actionBarColor: "#abcdef",
          actionBarTitle: "Example App",
          allViewTitle: "All Photos",
          useDetailsView: false,
          selectCircleStrokeColor: "#000000",
        ),
      );
    } on Exception catch (e) {
      print(e);
    }

    // If the widget was removed from the tree while the asynchronous platform
    // message was in flight, we want to discard the reply rather than calling
    // setState to update our non-existent appearance.
    if (!mounted) return;
    setState(() {
      images = resultList;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: FloatingActionButton(
        heroTag: "btn1",
        backgroundColor: ColorHelper.orange,
        child: Icon(Icons.add_photo_alternate),
        onPressed: loadAssets,
      ),
      appBar: new AppBar(
        title: Text('បញ្ជីរូបភាព'),
        backgroundColor: ColorHelper.orange,
      ),
      body: Column(
        children: <Widget>[
          //Error message
          errorMessage != "" ? 
          Container(
            margin: EdgeInsets.only(left: 10, right: 10, top: 10),
            height: 50,
            decoration: BoxDecoration(
              borderRadius: BorderRadius.all(Radius.circular(4)),
              color: ColorHelper.red.withOpacity(0.5),
            ),
            child: Center(
              child: Text("$errorMessage", style: TextStyle(color: ColorHelper.swhite, fontSize: 15),),
            ),
          ):
          Container(),

          Expanded(
            child: Container(
              margin: EdgeInsets.only(left: 10, right: 10, top: 10),
              child: buildGridView(),
            ),
          ),
          SafeArea(
            child: Container(
              margin: EdgeInsets.all(10),
              decoration: BoxDecoration(
                color: ColorHelper.green,
                borderRadius: BorderRadius.all(Radius.circular(4))
              ),
              height: 50,
              child: InkWell(
                onTap: () {
                  if(images.length > 0) {
                    setState(() {
                      errorMessage = "";
                    });
                    // Call function upload multiple files
                    _uploadFiles();
                  } else {
                    setState(() {
                      errorMessage = "សូមបញ្ជូលរូបភាព";
                    });
                  } 
                },
                child: Center(
                  child: Text("រួចរាល់", style: TextStyle(color: ColorHelper.swhite, fontSize: 15, fontWeight: FontWeight.w500,),),
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}

当您从图库中选择图像时，调用 getFileList() 然后调用设置状态，首先使用文件列表的全局变量，并在您再次选择图像时每次清除此列表。

  List<File> listFile = List<File>();
  images = resultList;
  _error = error;
   getFileList();

 void getFileList() async{
  listFile.clear();
 for(int i=0; i<images.length; i++){
  var path= await images[i].filePath;
  print(path);
  var file=await getImageFileFromAssets(path);
  print(file);
  listFile.add(file);
}
 setState(() {

 });
}

getImageFileFromAsset 用于将资源转换为文件

Future<File> getImageFileFromAsset(String path) async {
final file = File(path);
return file;

}

并在formdata中使用listFile。