我有以下代码。我正在尝试将图像上传到Firebase Storage并在对应的单元格中填充每个图像。当我运行程序时，出现致命错误：索引超出了范围：
cell.adImageView.image = fotografiiProfil[nrTotalProduse - indexPath.row - 1]
您能找到结果为什么会这样吗？
import UIKit
import Firebase
import FirebaseFirestore
import FirebaseStorage
class AnunturiViewController: UITableViewController {
// MARK: - Properties
/*****************************************/
var anunturi: [Produs] = [Produs]()
var docRef: CollectionReference!
var docRefNrTotalProduse: DocumentReference!
let imageNames = ["sneakers", "tshirt", "hoodie", "jacket", "pants", "accessory"]
let activityIndicator = UIActivityIndicatorView()
var fotografiiProfil: [UIImage] = []
var nrTotalProduse: Int = 0
var isDone: Bool!
// MARK: - Application Methods
/*****************************************/
override func viewDidLoad() {
super.viewDidLoad()
isDone = false
activityIndicator.activityIndicatorViewStyle = .gray
activityIndicator.center = self.view.center
activityIndicator.hidesWhenStopped = true
activityIndicator.startAnimating()
self.view.addSubview(activityIndicator)
self.tableView.tableFooterView = UIView(frame: CGRect(x: 0, y: 0, width: self.view.frame.width, height: 49))
docRefNrTotalProduse = Firestore.firestore().collection("anunturi").document("anunturi")
reloadTableView()
}
// MARK: - TableView Delegate and DataSource Methods
/*****************************************/
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "ADCell") as! ADTableViewCell
if isDone == true {
print(indexPath.row)
cell.adImageView.image = fotografiiProfil[nrTotalProduse - indexPath.row - 1]
cell.numeLabel.text = self.anunturi[nrTotalProduse - indexPath.row - 1].nume
cell.descriereLabel.text = self.anunturi[nrTotalProduse - indexPath.row - 1].descriere
cell.marimeLabel.text = self.anunturi[nrTotalProduse - indexPath.row - 1].marime
cell.locatieLabel.text = self.anunturi[nrTotalProduse - indexPath.row - 1].locatie
cell.pretLabel.text = self.anunturi[nrTotalProduse - indexPath.row - 1].pret
switch self.anunturi[nrTotalProduse - indexPath.row - 1].categorie {
case "sneakers":
cell.categorieImageView.image = UIImage(named: self.imageNames[0])
break
case "tricouri":
cell.categorieImageView.image = UIImage(named: self.imageNames[1])
break
case "bluze":
cell.categorieImageView.image = UIImage(named: self.imageNames[2])
break
case "jachete":
cell.categorieImageView.image = UIImage(named: self.imageNames[3])
break
case "pantaloni":
cell.categorieImageView.image = UIImage(named: self.imageNames[4])
break
case "accesorii":
cell.categorieImageView.image = UIImage(named: self.imageNames[5])
break
default:
break
}
}
return cell
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return nrTotalProduse
}
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 164.0
}
// MARK: - IBACtions
/*****************************************/
@IBAction func onRefreshButtonPressed(_ sender: UIBarButtonItem) {
reloadTableView()
}
// MARK: - Fetch Data From Firestore
/*****************************************/
func reloadTableView() {
fetchDataForNumberOfProducts()
}
func fetchData() {
anunturi.removeAll()
docRef = Firestore.firestore().collection("anunturi")
docRef.getDocuments() { (querySnapshot, error) in
if let error = error {
print("Error getting documents: \(error)")
} else {
for document in querySnapshot!.documents {
let data = document.data()
if document == querySnapshot?.documents.last {
self.fetchImages()
} else {
let produs = Produs(nume: (data["nume"] as? String)!,
descriere: (data["descriere"] as? String)!,
marime: (data["marime"] as? String)!,
produsNou: (data["produsNou"] as? Bool)!,
fotografii: (data["fotografii"] as? [String])!,
locatie: (data["locatie"] as? String)!,
livrezTara: (data["livrezTara"] as? Bool)!,
email: (data["email"] as? String)!,
telefon: (data["telefon"] as? String)!,
pret: (data["pret"] as? String)!,
autor: (data["autor"] as? String)!,
categorie: (data["categorie"] as? String)!)
self.anunturi.append(produs)
}
}
}
}
}
func fetchImages() {
for i in 0...(nrTotalProduse - 1) {
let storage = Storage.storage()
let storageRef = storage.reference()
let imageRef = storageRef.child("fotografii/" + anunturi[i].fotografii[0])
imageRef.getData(maxSize: 1024 * 1024 * 1024) { (data, error) in
if error != nil {
print(error!.localizedDescription)
} else {
self.fotografiiProfil.append(UIImage(data: data!)!)
if i == self.nrTotalProduse - 1 {
self.doneFetching()
}
}
}
}
}
func doneFetching() {
isDone = true
tableView.reloadData()
activityIndicator.stopAnimating()
}
func fetchDataForNumberOfProducts() {
docRefNrTotalProduse = Firestore.firestore().collection("anunturi").document("anunturi")
docRefNrTotalProduse.getDocument { (snapshot, error) in
if error != nil { print(error ?? "0") }
else {
let data = snapshot?.data()
self.nrTotalProduse = data!["numarAnunturi"] as! Int
self.fetchData()
}
}
}
}
答案 0 :(得分：0)
fotografiiProfil[]的索引不能小于0。
var num = indexPath.row -1
if nrTotalProduce = num && num < fotografiiProfil.count {
cell.adImageView.image = fotografiiProfil[num]
}
答案 1 :(得分：0)
评估索引：nrTotalProduse - indexPath.row - 1。
它不能低于0或超出数组fotografiiProfil的最后一项（长度-1）。
在实际分配索引值之前添加索引值的打印内容将有助于您调试代码。
添加：
print(indexPath.row)
print(nrTotalProduse)
print(nrTotalProduse - indexPath.row - 1)
答案 2 :(得分：0)
基于我们试图解决帖子中错误的困惑，我决定举一个例子说明我已经完成了自己的工作（至少我认为自己正在做的事情） 。有一些清理工作将使您的代码更易于理解和更高效。首先，我不确定为什么要进行数学运算而不是使用indexPath.row来计算数组的索引。那正是您的问题所在。这段代码有望清除如何使您的数据共享相同的索引，从而避免您进行计算。
首先，我定义了一个类（与您一样）来保存数据库中存储的数据。这是该课程：
class Angel {
var name: String?
var email: [String]? // multiple Emails
var phone: [String]? // multiple Numbers
var photo: UIImage? // variable to hold image
var filepath: String? // variable to hold image URL
}
接下来，我创建了一个数据源单例，以在应用程序的所有页面之间共享数据。此数据源还有更多内容，但就本示例而言，这是您需要查看的内容：
class PageDataSource {
/**
Store for Angel, User, CRUD, and Checkin info
*/
var angels = [Angel]() // array to hold the Angel objects
var crudIsAvailable: Bool? // check for connection stored variable
// singleton for global access
static let sharedInstance = PageDataSource()
private init() {}
}
将Angel对象存储到Firebase之后，我不得不编写一种方法来检索它：
// Read function to download the data from Firebase
func readAngels(completion: @escaping (_ error: NSError?) -> Void) {
if PageDataSource.sharedInstance.crudIsAvailable == true { // check for connection
Database.database().reference().child("angels").child(id).observeSingleEvent(of: .value) { (snapshot) in
print(snapshot)
var angels = [Angel]() // array to store firebase data
if let snapshots = snapshot.children.allObjects as? [DataSnapshot] {
for snap in snapshots { // loop through each angel object stored in the database
var angel = Angel()
if let dict = snap.value as? Dictionary<String, AnyObject> {
angel.name = dict["name"] as? String ?? ""
angel.email = dict["email"] as? [String] ?? [""]
angel.phone = dict["phone"] as? [String] ?? [""]
angel.filepath = dict["photo"] as? String ?? "" // get filepath for photo download
angels.append(angel) // add new angel to array
}
}
PageDataSource.sharedInstance.angels = angels // set new array of angels as the loaded angels in singleton
completion(nil)
} else {
completion(NSError(domain: "Error reading Snapshots", code: 99, userInfo: nil))
}
}
} else {
completion(NSError(domain: "Unavailable", code: 0, userInfo: nil))
}
}
调用readAngels()函数：
// using the readAngels() function to load angels
readAngels(completion: { (err) in
if err != nil {
print(err!.localizedDescription)
} else {
// do proper segue. No angels = sign up, 1 or more = login
if PageDataSource.sharedInstance.angels.count == 0 {
// User exists but no angels have been stored
self.performSegue(withIdentifier: "signUpSegue", sender: self)
} else {
// Stored angels detected, proceed with app flow
self.performSegue(withIdentifier: "logInSegue", sender: self)
}
}
})
调用readAngels()函数后，我将加载tableView。布置单元格后，我读取了存储在数据源中的数据并填充了单元格。如果在数据源中有一张已经被解码的照片被立即加载。如果没有，我使用filepath中的datasource来检索图像：
// tableView function to populate cells
// this will load images asyncronously as the cells are displayed on the screen
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = UITableViewCell(style: .default, reuseIdentifier: "CellID") // set cell for reuse
// check for image already loaded in Datasource
if let pic = PageDataSource.sharedInstance.angels[indexPath.row].photo {
// if image is already available set imageView content
cell.imageView?.image = pic
cell.setNeedsLayout()
// if no image in Datasource pull it from firebase storage
} else if let imgURL = PageDataSource.sharedInstance.angels[indexPath.row].filepath {
Storage.storage().reference(forURL: imgURL).getData(maxSize: INT64_MAX, completion: { (data, error) in
guard error == nil else {
print("error downloading: \(error!)")
return
}
// render
let img = UIImage.init(data: data!)
// store to datasource
PageDataSource.sharedInstance.angels[indexPath.row].photo = img
// display img
if cell == tableView.cellForRow(at: indexPath){
DispatchQueue.main.async {
cell.imageView?.image = img
cell.setNeedsLayout()
}
}
})
} else {
cell.imageView?.image = UIImage(contentsOfFile: "Placeholder.png")
}
// set text
cell.textLabel?.text = PageDataSource.sharedInstance.angels[indexPath.row].name
return cell
}