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, color: Colors.white, 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),
),
color: Colors.purple,
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,
color: Colors.purple,
size: 36,
),
title: Container(
width: 250.0,
child: TextField(
style: TextStyle(color: Colors.black),
controller: locationTextEditingController,
decoration: InputDecoration(
hintText: "Add location",
hintStyle: TextStyle(color: Colors.grey),
border: InputBorder.none,
),
),
),
),
Container(
width: 220,
height: 50,
alignment: Alignment.center,
child: RaisedButton.icon(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(35)),
color: Colors.purple,
icon: Icon(
Icons.location_on,
color: Colors.white,
),
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",
style: TextStyle(color: Colors.grey)),
onPressed: upLoadImageFromGallery,
),
SimpleDialogOption(
child: Text("Done", style: TextStyle(color: Colors.grey)),
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();
});
}
}