如何使用Flutter将图像上传到Firebase

Question

我正在使用image_picker库https://pub.dartlang.org/packages/image_picker 来选择/拍摄我要上传的照片.到目前为止,代码已成功将图像上传到Firebase存储,唯一的问题是图像上传后应用程序关闭(不会真正崩溃,只是关闭,VS代码无法连接到设备).代码如下:

 File _image;

  Future _takeProfilePicture() async{
    var image = await ImagePicker.pickImage(source: ImageSource.camera);

    setState((){
      _image = image;
    });
  }

  Future _selectProfilePicture() async{
    var image = await ImagePicker.pickImage(source: ImageSource.gallery);

    setState((){
      _image = image;
    });
  }

  Future<Null> _uploadProfilePicture() async{
    FirebaseUser user = await FirebaseAuth.instance.currentUser();

    final StorageReference ref = FirebaseStorage.instance.ref().child('${user.email}/${user.email}_profilePicture.jpg');
    final StorageUploadTask uploadTask = ref.putFile(_image);
    final Uri downloadUrl = (await uploadTask.future).downloadUrl;
  }

  void _selectAndUploadPicture() async{
    await _selectProfilePicture();
    await _uploadProfilePicture();
  }

  void _takeAndUploadPicture() async{
    await _takeProfilePicture();
    await _uploadProfilePicture();
  }

终端打印以下内容:

W/Firestore( 6873): (0.6.6-dev) [Firestore]: The behavior for java.util.Date objects stored in Firestore is going to change AND YOUR APP MAY BREAK.
W/Firestore( 6873): To hide this warning and ensure your app does not break, you need to add the following code to your app before calling any other Cloud Firestore methods:
W/Firestore( 6873):
W/Firestore( 6873): FirebaseFirestore firestore = FirebaseFirestore.getInstance();
W/Firestore( 6873): FirebaseFirestoreSettings settings = new FirebaseFirestoreSettings.Builder()
W/Firestore( 6873):     .setTimestampsInSnapshotsEnabled(true)
W/Firestore( 6873):     .build();
W/Firestore( 6873): firestore.setFirestoreSettings(settings);
W/Firestore( 6873):
W/Firestore( 6873): With this change, timestamps stored in Cloud Firestore will be read back as com.google.firebase.Timestamp objects instead of as system java.util.Date objects. So you will also need to update code expecting a java.util.Date to instead expect a Timestamp. For example:
W/Firestore( 6873):
W/Firestore( 6873): // Old:
W/Firestore( 6873): java.util.Date date = snapshot.getDate("created_at");
W/Firestore( 6873): // New:
W/Firestore( 6873): Timestamp timestamp = snapshot.getTimestamp("created_at");
W/Firestore( 6873): java.util.Date date = timestamp.toDate();
W/Firestore( 6873):
W/Firestore( 6873): Please audit all existing usages of java.util.Date when you enable the new behavior. In a future release, the behavior will be changed to the new behavior, so if you do not follow these steps, YOUR APP MAY BREAK.

我尝试从终端实现建议的java代码,但我似乎找不到使用cloud_firestore库https://pub.dartlang.org/packages/cloud_firestore在flutter中编写等效的方法,它没有FirebaseFirestoreSettings的等价物(或者我似乎找不到一个).有没有解决的办法？

先感谢您!

Answer 1

更新版本的mmccabe的答案适用于firebase_storage 1.0.4插件的版本

Future<String> _pickSaveImage(String imageId) async {
  File imageFile = await ImagePicker.pickImage(source: ImageSource.camera);
  StorageReference ref =
    FirebaseStorage.instance.ref().child(imageId).child("image.jpg");
  StorageUploadTask uploadTask = ref.putFile(imageFile);
  return await (await uploadTask.onComplete).ref.getDownloadURL();
}

截至目前,您必须这样做:

var downloadURL =(等待uploadTask.onComplete).ref.getDownloadURL();

因为错误:没有为"StorageUploadTask"类定义getter"future".([timetracker]的undefined_getter lib/screens/image_detection.dart:63)

Answer 2

以下对我有用：

Future<Uri> _pickSaveImage(String imageId) async {
  File imageFile = await ImagePicker.pickImage(source: ImageSource.camera);
  StorageReference ref =
    FirebaseStorage.instance.ref().child(imageId).child("image.jpg");
  StorageUploadTask uploadTask = ref.putFile(imageFile);
  return (await uploadTask.future).downloadUrl;
}