将多张图片上传到 Firestore 时出错

如何解决将多张图片上传到 Firestore 时出错

我在使此代码正常工作时遇到问题。我反复查看了代码中的错误，但我没有发现任何错误。我的猜测是问题可能出在我的互联网连接上，但我想加倍确定。

有人可以帮我检查我的代码吗，很可能我做错了什么。

首先，在正文部分，应该显示用户的个人资料图片。它显示一个错误（“profilePic was called on null”）。我不知道为什么；

leading: CircleAvatar(
           backgroundImage:
               CachednetworkImageProvider(widget.user.profilePic),),

此外，当我尝试上传多张图片时，只会上传第一张图片，并且不会在 Cloud Firestore 中自动创建集合。

请参阅下面的完整代码。我真的很感激这里有人的帮助；

final postsReference = FirebaseFirestore.instance.collection("posts");
final StorageReference storageReference =
    FirebaseStorage.instance.ref().child("Uploads");

class PhotoUpload extends StatefulWidget {
  final z.User user;

  PhotoUpload({this.user});

  @override
  _PhotoUploadState createState() => _PhotoUploadState();
}

class _PhotoUploadState extends State<PhotoUpload>
    with AutomaticKeepAliveClientMixin<PhotoUpload> {


  List<File> _image = [];
  final picker = ImagePicker();
  String postId = Uuid().v4();
  bool uploading = false;
  TextEditingController descriptionTextEditingController =
      TextEditingController();
  TextEditingController locationTextEditingController = TextEditingController();

  bool get wantKeepAlive => true;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: FloatingActionButton(
        backgroundColor: Colors.purple,onpressed: () => controlImageUpload(),child: Icon(
          Icons.send,size: 32,color: Colors.white,appBar: AppBar(
        backgroundColor: Colors.purple,centerTitle: true,title: Text(
          "Image Upload",style: TextStyle(
              fontSize: 20.0,fontWeight: FontWeight.bold),body: Column(
        children: <Widget>[
          uploading ? linearProgress() : Text(""),Expanded(
            child: GridView.builder(
                itemCount: _image.length + 1,gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
                    crossAxisCount: 3),itemBuilder: (context,index) {
                  return index == 0
                      ? Column(
                          mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[
                              IconButton(
                                icon: Icon(Icons.camera_alt,color: Colors.purple,size: 40.0),onpressed: () =>
                                    !uploading ? captureImage(context) : null,Padding(
                                padding: const EdgeInsets.all(2.0),child: RaisedButton(
                                  shape: RoundedRectangleBorder(
                                      borderRadius:
                                          BorderRadius.circular(35.0)),child: Text(
                                    "Load Image",style: TextStyle(
                                        color: Colors.white,fontSize: 14.0),onpressed: () => captureImage(context),])
                      : Container(
                          margin: EdgeInsets.all(3),decoration: Boxdecoration(
                              image: decorationImage(
                                  image: FileImage(_image[index - 1]),fit: BoxFit.cover)),);
                }),ListTile(
            leading: CircleAvatar(
               backgroundImage:
                   CachednetworkImageProvider(widget.user.profilePic),title: Container(
              width: 250.0,child: TextField(
                style: TextStyle(color: Colors.black),controller: descriptionTextEditingController,decoration: Inputdecoration(
                  hintText: "Say something!",hintStyle: TextStyle(color: Colors.grey),border: InputBorder.none,Divider(),ListTile(
            leading: Icon(
              Icons.person_pin_circle,size: 36,controller: locationTextEditingController,decoration: Inputdecoration(
                  hintText: "Add location",Container(
            width: 220,height: 50,alignment: Alignment.center,child: RaisedButton.icon(
              shape: RoundedRectangleBorder(
                  borderRadius: BorderRadius.circular(35)),icon: Icon(
                Icons.location_on,label: Text(
                "Get my location",style: TextStyle(color: Colors.white),onpressed: getUserCurrentLocation,],);
  }


  upLoadImageFromgallery() async {
    final pickedFile = await picker.getimage(source: ImageSource.gallery);

    setState(() {
      _image.add(File(pickedFile?.path));
    });
    if (pickedFile.path == null) {
      retrieveLostData();
    }
  }

  captureImageWithCamera() async {
    final pickedFile = await picker.getimage(source: ImageSource.camera);

    setState(() {
      _image.add(File(pickedFile?.path));
    });
    if (pickedFile.path == null) {
      retrieveLostData();
    }
  }

  captureImage(mContext) {
    return showDialog(
        context: mContext,builder: (context) {
          return simpledialog(
            title: Text("New Upload",style:
                    TextStyle(color: Colors.grey,fontWeight: FontWeight.bold)),children: <Widget>[
              simpledialogOption(
                child: Text("Capture with Camera",style: TextStyle(color: Colors.grey)),onpressed: captureImageWithCamera,simpledialogOption(
                child: Text("Select from gallery",onpressed: upLoadImageFromgallery,simpledialogOption(
                child: Text("Done",onpressed: () => Navigator.pop(context),);
        });
  }

  Future<void> retrieveLostData() async {
    final LostData response = await picker.getLostData();
    if (response.isEmpty) {
      return;
    }
    if (response.file != null) {
      setState(() {
        _image.add(File(response.file.path));
      });
    } else {
      print(response.file);
    }
  }

  Future<String> uploadPhoto() async {
    for (var img in _image) {
      StorageUploadTask mStorageUploadTask = storageReference
          .child('images/${Path.basename(img.path)}')
          .putFile(img);
      StorageTaskSnapshot storageTaskSnapshot =
          await mStorageUploadTask.onComplete;
      String downloadUrl = await storageTaskSnapshot.ref.getDownloadURL();

      return downloadUrl;
    }
  }

  
  getUserCurrentLocation() async {
    Position position = await Geolocator.getCurrentPosition(
        desiredAccuracy: LocationAccuracy.high);
    List<Placemark> placeMarks =
        await placemarkFromCoordinates(position.latitude,position.longitude);
    Placemark mPlaceMark = placeMarks[0];
    String completeAddressInfo =
        '${mPlaceMark.subThoroughfare} ${mPlaceMark.thoroughfare},${mPlaceMark.subLocality} ${mPlaceMark.locality},${mPlaceMark.subAdministrativeArea} ${mPlaceMark.administrativeArea},${mPlaceMark.postalCode} ${mPlaceMark.country},';
    String cityStateCountry =
        '${mPlaceMark.subLocality},${mPlaceMark.locality},${mPlaceMark.country}';
    locationTextEditingController.text = cityStateCountry;
  }

  saveImageInfoToFireStore({String url,String location,String description}) {
    postsReference
        .doc(widget.user.id)
        .collection("postimages")
        .doc(postId)
        .set({
      "postId": postId,"ownerId": widget.user.id,"timestamp": timestamp,"likes": {},"dislikes": {},"username": widget.user.username,"description": description,"location": location,"url": url,});
  }

  controlImageUpload() async {
    setState(() {
      uploading = true;
    });

    String downloadUrl = await uploadPhoto();

    saveImageInfoToFireStore(
        url: downloadUrl,location: locationTextEditingController.text,description: descriptionTextEditingController.text);

    locationTextEditingController.clear();
    descriptionTextEditingController.clear();

    setState(() {
      _image = [];
      uploading = false;
      postId = Uuid().v4();
    });
  }
}