“無法轉換：'_Uri' 實例”在 flutter web 上的 Cloud Firestore 最新版本上上傳圖像時出錯

Question

使用最新版本的cloud_firestore: ^0.14.0+2出現以下錯誤cloud_firestore: ^0.14.0+2在雲cloud_firestore: ^0.14.0+2上傳圖像時。

Uncaught (in promise) Error: [cloud_firestore/unknown] Invalid argument (dartObject): Could not convert: Instance of '_Uri'

圖像已成功上傳到存儲部分，但圖像鏈接未在 cloud firestore db 中更新。

下面是我從中選擇圖像並點擊他上傳 btn 上傳圖像的課程

class AddNewItemView extends StatefulWidget {
  @override
  _AddNewItemViewState createState() => _AddNewItemViewState();
}

class _AddNewItemViewState extends State<AddNewItemView> {
  MediaInfo _itemPic; 
 @override
  Widget build(BuildContext context) {
    return Scaffold(
    .....
    child: RawMaterialButton(
          onPressed: () async {
              MediaInfo pickedImg =  await ImagePickerWeb.getImageInfo; <---- image_picker_web package
               setState(() {
                 _itemPic = pickedImg;
                });
    .........
    FlatButton(
         onPressed: () async {
            bool addDataSuccess = await model.addNewItem( _itemPic);
            if (addDataSuccess) {
                 print("Inside addDataSuccess");
            } else {
                 print("Outside addDataSuccess");
                   }
                 },
              ),
    .....
    );
}

該類負責從uploadImageFile函數中提取圖片uri並上傳到cloud firestore 。 與圖片一起傳遞的任何其他信息都會上傳到雲防火牆中，只有“圖片”沒有上傳

class ItemViewModel extends BaseViewModel {
           Future<bool> addNewItem(   MediaInfo pic ) async {
         
                 Uri _uploadedImgURL = await ConstantFtns()
                     .uploadImageFile(pic, "ImgPathString", "fileName");


     await  FirebaseFirestore.instance.collection('item').doc("tempID").set(
        {
              'pic': _uploadedImgURL,
          'otherInfo': 'otherTempInfo' 
    },
        );
}

在下面的課程中，我得到了有效的imageUri沒有任何錯誤，圖像被上傳到存儲部分，唯一的問題是它沒有被上傳到雲 Firestore 數據庫中

import 'package:firebase/firebase.dart' as fb;
import 'package:mime_type/mime_type.dart';
import 'package:path/path.dart' as p;

class ConstantFtns  {
  Future<Uri> uploadImageFile(
      MediaInfo mediaInfo, String ref, String fileName) async {
    try {
      String mimeType = mime(p.basename(mediaInfo.fileName));
       final String extension = extensionFromMime(mimeType);

      var metadata = fb.UploadMetadata(
        contentType: mimeType,
      );

      fb.StorageReference storageReference =
          fb.storage().ref(ref).child(fileName + ".$extension");

      fb.UploadTaskSnapshot uploadTaskSnapshot =
          await storageReference.put(mediaInfo.data, metadata).future;

      Uri imageUri = await uploadTaskSnapshot.ref.getDownloadURL();
      print("download url $imageUri");  <---- IT GETS P[RINTED AND IT SHOWED VALED IMAGE URL STORED IN STORAGE
      return imageUri;
    } catch (e) {
      print("File Upload Error $e");
      return null;
    }
  }
}

Answer 1

由於您想要的只是將 URL 存儲到 firestore 中，因此您實際上並不需要將getDownloadURL()值作為Uri對象，您只需要它的字符串值，這是您收到轉換錯誤的錯誤，我建議您遵循此社區答案中的建議，這樣您的代碼將如下所示：

String uploadImageFile(
    MediaInfo mediaInfo, String ref, String fileName) async {
        try {
            ...

            var imageUri = await uploadTaskSnapshot.ref.getDownloadURL() as String;
            print("download url $imageUri");  <---- IT GETS P[RINTED AND IT SHOWED VALED IMAGE URL STORED IN STORAGE
            return imageUri
        } catch (e) {
            ...
        }
    }
})

您還必須將ItemViewModel類中的調用更改為：

String _uploadedImgURL = await ConstantFtns()
                 .uploadImageFile(pic, "ImgPathString", "fileName");