ios - TableView 不显示单元格

Question

我是初学者，很抱歉，如果这是一个愚蠢的问题。我正在尝试创建一个从 Firebase Realtime DB API 加载数据的 TableView 。我想我设置正确，它不会引发任何错误或崩溃。但是，它也没有调用 cellsForRowAt 方法。因此，它不显示任何单元格。它显示了线条，它们可以滚动并弹跳，但它们是默认宽度。它确实调用了 numberOfRowsInSection 方法，我已经通过控制台日志验证了这一点。这是整个 View Controller ...

class UpcomingTableViewController: UITableViewController {


    var upcomingPosts = [upcomingPost]()

    override func viewDidLoad() {
        super.viewDidLoad()
        print("loaded")
        let ref: DatabaseReference
        ref = Database.database().reference()
        let dbref = ref.child("auctionHandler").child("upcoming")
        dbref.queryOrderedByKey().observe(DataEventType.childAdded, with: { (snapshot) in
            let snapshot = snapshot.value as! NSDictionary
            let shoe = snapshot["name"] as! String
            let colorway = snapshot["colorway"] as! String
            let date = snapshot["date"] as! String
            let newPost = upcomingPost(shoe: shoe, colorway: colorway, date: date)
            self.upcomingPosts.insert(newPost, at: 0)
            //print(self.upcomingPosts)
            self.tableView.reloadData()
        })
    }
    override func viewDidAppear(_ animated: Bool) {
        self.tableView.reloadData()
    }
    override func numberOfSections(in tableView: UITableView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return 0
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        // #warning Incomplete implementation, return the number of rows
        print(upcomingPosts.count)
        return upcomingPosts.count
    }
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        print("ran")
        let cell = tableView.dequeueReusableCell(withIdentifier: "upcoming", for: indexPath)

        let shoe = cell.viewWithTag(1) as! UILabel
         shoe.text = upcomingPosts[indexPath.row].shoe

        let colorway = cell.viewWithTag(2) as! UILabel
         colorway.text = upcomingPosts[indexPath.row].colorway
        print(cell)
        print("------")
        return cell
    }
}

在此先感谢您的帮助!

更新:我删除了 numberOfSections，它抛出了这个崩溃

(
    0   CoreFoundation                      0x00007fff23c4f02e __exceptionPreprocess + 350
    1   libobjc.A.dylib                     0x00007fff50b97b20 objc_exception_throw + 48
    2   CoreFoundation                      0x00007fff23c4ebf9 -[NSException raise] + 9
    3   Foundation                          0x00007fff256f2ef3 -[NSObject(NSKeyValueCoding) setValue:forKey:] + 325
    4   UIKitCore                           0x00007fff47d3410f -[UIView(CALayerDelegate) setValue:forKey:] + 171
    5   UIKitCore                           0x00007fff474b9a32 -[UIRuntimeOutletConnection connect] + 109
    6   CoreFoundation                      0x00007fff23c3b052 -[NSArray makeObjectsPerformSelector:] + 242
    7   UIKitCore                           0x00007fff474b6bda -[UINib instantiateWithOwner:options:] + 2190
    8   UIKitCore                           0x00007fff47a3a229 -[UITableView _dequeueReusableViewOfType:withIdentifier:] + 610
    9   UIKitCore                           0x00007fff47a3a865 -[UITableView _dequeueReusableCellWithIdentifier:forIndexPath:usingPresentationValues:] + 496
    10  UIKitCore                           0x00007fff47a3a641 -[UITableView dequeueReusableCellWithIdentifier:forIndexPath:] + 91
    11  Sole Club                           0x000000010e306031 $s9Sole_Club27UpcomingTableViewControllerC05tableE0_12cellForRowAtSo07UITableE4CellCSo0lE0C_10Foundation9IndexPathVtF + 577
    12  Sole Club                           0x000000010e3068c5 $s9Sole_Club27UpcomingTableViewControllerC05tableE0_12cellForRowAtSo07UITableE4CellCSo0lE0C_10Foundation9IndexPathVtFTo + 165
    13  UIKitCore                           0x00007fff47a5468e -[UITableView _createPreparedCellForGlobalRow:withIndexPath:willDisplay:] + 781
    14  UIKitCore                           0x00007fff47a1d667 -[UITableView _updateVisibleCellsNow:] + 3081
    15  UIKitCore                           0x00007fff47a3d78b -[UITableView layoutSubviews] + 194
    16  UIKitCore                           0x00007fff47d34d01 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 2478
    17  QuartzCore                          0x00007fff2b138d41 -[CALayer layoutSublayers] + 255
    18  QuartzCore                          0x00007fff2b13ef33 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 517
    19  QuartzCore                          0x00007fff2b14a86a _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 80
    20  QuartzCore                          0x00007fff2b0917c8 _ZN2CA7Context18commit_transactionEPNS_11TransactionEd + 324
    21  QuartzCore                          0x00007fff2b0c6ad1 _ZN2CA11Transaction6commitEv + 643
    22  QuartzCore                          0x00007fff2b0c743a _ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 76
    23  CoreFoundation                      0x00007fff23bb1617 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
    24  CoreFoundation                      0x00007fff23bac0ae __CFRunLoopDoObservers + 430
    25  CoreFoundation                      0x00007fff23bac72a __CFRunLoopRun + 1514
    26  CoreFoundation                      0x00007fff23babe16 CFRunLoopRunSpecific + 438
    27  GraphicsServices                    0x00007fff38438bb0 GSEventRunModal + 65
    28  UIKitCore                           0x00007fff4784fb48 UIApplicationMain + 1621
    29  Sole Club                           0x000000010e3236bb main + 75
    30  libdyld.dylib                       0x00007fff51a1dc25 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

更新:错误消息标题

*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<UITableViewCell 0x7fdc62e847f0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key colorway.'
*** First throw call stack:

Answer 1

删除这个

override func numberOfSections(in tableView: UITableView) -> Int {
    // #warning Incomplete implementation, return the number of sections
    return 0
}

你告诉表格 num of sections 将是 0 ，然后你希望它如何显示任何东西

---

尝试

var once  = true // add this as an instance var 

         self.upcomingPosts.insert(newPost, at: 0) 
         if once {
            DispatchQueue.main.asyncAfter(deadline: .now() + 1.0 ) {
               self.tableView.reloadData()
               self.once = false
            }   
         }