Swift 从VC1中的firebase检索用户数据并将其发送到VC2中要显示的TableView时出现问题
我从firebase firestore检索所有数据时遇到问题（firebase firestore跟踪一些用户信息，即标题、说明和图像URL），然后从firebase Storage下载图像，创建一个名为Cella的对象（标题：字符串、说明：字符串、图像：UIImage）。这个过程应该在一个循环中进行，然后为每个用户创建一个对象，并返回一个Cella对象数组，该数组将传递给另一个ViewController并显示在其tableView上 我试图修复完成处理程序，因为我认为它们是问题所在，然后我添加了一个IBAction，它在执行segue时被触发 我尝试检索数据的ViewController（请注意，它位于导航视图控制器内，并且segue是唯一一个，当按下该按钮时会触发） 表视图所在的ViewController：Swift 从VC1中的firebase检索用户数据并将其发送到VC2中要显示的TableView时出现问题,swift,firebase,google-cloud-firestore,tableview,Swift,Firebase,Google Cloud Firestore,Tableview,我从firebase firestore检索所有数据时遇到问题（firebase firestore跟踪一些用户信息，即标题、说明和图像URL），然后从firebase Storage下载图像，创建一个名为Cella的对象（标题：字符串、说明：字符串、图像：UIImage）。这个过程应该在一个循环中进行，然后为每个用户创建一个对象，并返回一个Cella对象数组，该数组将传递给另一个ViewController并显示在其tableView上 我试图修复完成处理程序，因为我认为它们是问题所在，然后我
class ViewControllerForTable: UIViewController, UITableViewDataSource, UITableViewDelegate {
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let currentCell = tableView.cellForRow(at: indexPath) as! TableViewCell
let information = Information(title: currentCell.title.text!, description: currentCell.bodyText.text!, sellerImage: currentCell.CellImage.image!)
let destinationVC = self.storyboard?.instantiateViewController(withIdentifier: "ViewControllerDisplay") as! ViewControllerDisplay
destinationVC.dataPassed = information
self.navigationController?.pushViewController(destinationVC, animated: true)
}
@IBOutlet weak var UITableView: UITableView!
let image : UIImage = UIImage(named: "image1")!
var cells : [Cella] = []
override func viewDidLoad() {
super.viewDidLoad()
//states that this class is the delegate of the data and the object tableView within this VC
UITableView.delegate = self
UITableView.dataSource = self
//force sets each of the the tableView rows to have a height of 200
UITableView.rowHeight = 200
// Do any additional setup after loading the view.
}
//Function hardcoded that creates the 5 cells to test the app
//MARK - Table view settings
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
//meaning my UITableView is going to have cells.count different rows
return cells.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
//Gets each item singularly in order from the dictionary of cells
let cellFormat = cells[indexPath.row]
//You need to do this Nib thing because you created a xib file
let nib = UINib(nibName: String(describing: TableViewCell.self), bundle: nil)
tableView.register(nib, forCellReuseIdentifier: "customCell")
// Says that it is going to create a reusable cell with the identifier from the XIB file and it is going to use the class TableViewCell to access its properties
let cellObject = tableView.dequeueReusableCell(withIdentifier: "customCell", for: indexPath) as! TableViewCell
//Creates and assigns the values from the item in the dictionary to the CellFormat for them to be displayed in the custom cell
cellObject.setCell(cellFormatTaken: cellFormat)
// returns the final Cell Item
return cellObject
}
@IBAction func unwindToActivitieslList(sender: UIStoryboardSegue) {
let sourceViewController = sender.source as? ViewController
let activities = sourceViewController?.cellaObjects
cells = activities!
UITableView.reloadData()
}
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
super.prepare(for: segue, sender: sender)
getDocumentsFromFirestore(firestoreReference: firestoreUsersReference) { (cellaArray) in
self.cellaObjects = cellaArray
}
}
我还按照好心的建议添加了调度。尽管我无法获得要显示的数据。我对该按钮的另一个问题是，每当我单击它时，由于VCs嵌入到导航控制器中，它们会创建一个“副本”目标ViewController，并且它在应用程序打开的整个过程中一直这样做，给我留下了许多重复的、空的行。您需要在
prepare（对于segue:getDocumentsFromFirestore(firestoreReference: firestoreUsersReference) { (cellaArray) in
self.cellaObjects = cellaArray
self.performSegue(withIdentifier:"segue",sender:nil)
}
这里还需要
DispatchGroup（）func getDocumentsFromFirestore (firestoreReference: CollectionReference, completion: @escaping ([Cella])->()) {
var cellaArray : [Cella] = []
firestoreUsersReference.getDocuments { (querySnapshot, err) in
if err != nil {
print("There has been an error \(String(describing: err?.localizedDescription))")
}
else {
let g = DispatchGroup()
for documents in querySnapshot!.documents {
g.enter()
print("\(documents.documentID) => \(documents.data())")
let data = documents.data()
let title = data["userTitle"] as! String
let description = data["userDescription"] as! String
let imageURL = data["userImageURL"] as! String
print("Title: \(String(describing: title)), Description: \(String(describing: description)), imageURL: \(imageURL)")
self.cellCreationProcess(title: title, description: description, imageURL: imageURL, completion: { (newCell) in
cellaArray.append(newCell)
g.leave()
})
}
g.notify(queue: .main, execute: {
completion(cellaArray)
})
}
}
}
您需要在
prepare（对于segue:getDocumentsFromFirestore(firestoreReference: firestoreUsersReference) { (cellaArray) in
self.cellaObjects = cellaArray
self.performSegue(withIdentifier:"segue",sender:nil)
}
这里还需要
DispatchGroup（）func getDocumentsFromFirestore (firestoreReference: CollectionReference, completion: @escaping ([Cella])->()) {
var cellaArray : [Cella] = []
firestoreUsersReference.getDocuments { (querySnapshot, err) in
if err != nil {
print("There has been an error \(String(describing: err?.localizedDescription))")
}
else {
let g = DispatchGroup()
for documents in querySnapshot!.documents {
g.enter()
print("\(documents.documentID) => \(documents.data())")
let data = documents.data()
let title = data["userTitle"] as! String
let description = data["userDescription"] as! String
let imageURL = data["userImageURL"] as! String
print("Title: \(String(describing: title)), Description: \(String(describing: description)), imageURL: \(imageURL)")
self.cellCreationProcess(title: title, description: description, imageURL: imageURL, completion: { (newCell) in
cellaArray.append(newCell)
g.leave()
})
}
g.notify(queue: .main, execute: {
completion(cellaArray)
})
}
}
}
我试着按照你善意的建议去做，不幸的是我没能得到结果。我已经用遇到的问题更新了帖子。将segue源代码挂到vc本身，而不是挂到按钮。我也试过这样做，但同样的事情也发生了。为了简单起见，我已经将它上传到github的以下存储库中：如果这可能的话lpI已经试着按照你善意的建议做了，不幸的是我没能得到结果。我已经用遇到的问题更新了帖子。将segue源代码挂到vc本身，而不是挂到按钮。我也尝试过这样做，但同样的事情也发生了。为了简单起见，我已经将它上传到github的以下存储库中：如果可能的话
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