Question

下面显示的源代码，

数据库：

static func insertErrorLog(moduleName: String, message: String) {
    let dateToday = Date()
    let timestamp = Int(Date().timeIntervalSince1970)

    let db = Firestore.firestore()

    let docData: [String: Any] = [
        KDB.Fields.moduleName : moduleName,
        KDB.Fields.message : message,
        KDB.Fields.createdAt : dateToday
    ]

型号：

var uploadedAt: String = ""
var createdAt: String = ""

init(document: DocumentSnapshot) {
    self.key = document.documentID

    let json = JSON(document.data())

    self.storeId = json[KDB.Fields.storeId].stringValue
    self.imgName = json[KDB.Fields.imgName].stringValue
    self.title = json[KDB.Fields.title].stringValue
    self.description = json[KDB.Fields.description].stringValue
    self.sort = json[KDB.Fields.sort].intValue
    self.uploadedAt = json[KDB.Fields.uploadedAt].stringValue
    self.createdAt = json[KDB.Fields.createdAt].stringValue
}

init(key: String, storeId: String, imgName: String, title: String, description: String, sort: Int, uploadedAt: String, createdImageAt: String = "") {
    self.key = key
    self.storeId = storeId
    self.imgName = imgName
    self.title = title
    self.description = description
    self.sort = sort
    self.uploadedAt = uploadedAt
    self.createdAt = createdImageAt
}

控制器：

    query.getDocuments { (querySnapshot, error) in
        if let error = error {
            SpeedLog.print("Error: \(error.localizedDescription)")
        } else {
            var loop = 1
            for document in (querySnapshot?.documents)! {
                SpeedLog.print("documentDATA:\(document.data())")
                var photoObject = Photo(document: document)
                SpeedLog.print("photoObject:\(photoObject)")

                if (!photoObject.imgName.isEmpty) {
                    let storagePath = "\(photoObject.imgName)"
                    SpeedLog.print("Photo storagePath: \(storagePath)")

                    let storage = Storage.storage()
                    let storageRef = storage.reference()
                    let imageRef = storageRef.child(storagePath)

                    imageRef.getData(maxSize: 1 * 1024 * 1024) { data, error in
                        if let error = error {
                            SpeedLog.print("Photos download image error documentID:\(document.documentID) : \(error.localizedDescription)")
                        } else {
                            photoObject.imageData = UIImage(data: data!)
                            self.photos.append(photoObject)

                            if loop == 1 {
                                self.imageView.image = photoObject.imageData!
                                self.photoTitleLabel.text = "\(photoObject.title)"

                                    self.photoCreatedAtLabel.text = "\(photoObject.createdAt)"
                                    self.photoCreatedAtTitleLabel.isHidden = false
                                //}
                            }
                        }
                        self.collectionView.reloadData()
                        loop += 1
                    }
                }
            }
        }
    }
}

extension PhotoGalleryViewController: UICollectionViewDataSource, UICollectionViewDelegate {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return photos.count
}

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CellPhotoGallery", for: indexPath) as! PhotoGalleryCollectionViewCell

    configureCell(cell, atIndexPath: indexPath)

    return cell
}

func configureCell(_ cell: PhotoGalleryCollectionViewCell, atIndexPath indexPath: IndexPath) {

    let photo = photos[indexPath.row]

    if let image = photo.imageData {
        cell.imageView.image = image
    }
    photoLabel.text = photo.title
    photoCreatedAtLabel.text = photo.createdAt
}

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    let photo = photos[indexPath.row]

    if let image = photo.imageData {
        imageView.image = image
    }
    photoLabel.text = photo.title
    photoCreatedAtLabel.text = photo.createdAt
}

在Firebase中，我们有一个字段createdAt ：（时间戳记）

基本上，当我在Xcode中运行代码时，照片存储从firebase数据中获取createdAt，但是当涉及Photo Object“ self.photoCreatedAtLabel.text =”（photoObject.createdAt）“时，日期未显示。代码中可能缺少什么？请参阅申请附件以供参考。

编辑：添加了照片对象的控制台打印输出。

photoObject:Photo (
   key: "x2q0Asfjn2S8FYr6fIvA", 
   storeId: "", 
   imgName: "locator/stores/egdupo/BitoysVulcanizingandTireShop_rJTM7alkTp_M6L.jpg", 
   imageData: nil, 
   title: "", 
   description: "", 
   sort: 1, 
   uploadedAt: "", 
   createdAt: ""
)

有人吗？

谢谢。

Answer 1

从FireStore文档

当前，Firestore将时间戳字段返回为“日期”，但仅返回“日期” 支持毫秒精度，这会导致截断并导致在快照中使用时间戳作为一部分时的意外行为后续查询。

因此，如果要使用它，您的代码需要将其作为NSDate（日期）对象进行处理。但是，使用以下代码

let settings = Firestore.firestore().settings
settings.areTimestampsInSnapshotsEnabled = true

将timestampsInSnapshots设置为true将导致Firestore返回时间戳记值而不是日期，可避免截断。注意您还必须将使用Date的所有代码更改为使用Timestamp。

实际上，假设我们有一个文档集合，并且每个文档中的一个字段称为图章；这样写

let now = Date()
let stamp = Timestamp(date: now)
self.db.collection("timestamps").document("test_stamp_0").setData( [
   "stamp": stamp
])

然后读取该图章节点并将其格式化以在UI中输出

//read the document
if let stamp = document.get("stamp") {
    let title = document.documentID
    let ts = stamp as! Timestamp //force downcast stamp to a Timestamp cause' that's what it is.
    let aDate = ts.dateValue()
    let formatter = DateFormatter()
    formatter.dateFormat = "yyyy-MM-dd HH:mm:ss ZZZ"
    let formattedTimeZoneStr = formatter.string(from: aDate)
    print(title, formattedTimeZoneStr) //prints test_stamp_0, 2018-10-03 08:00:00 -0400
}

如何在Firebase中获取日期

1 个答案: