ios - UITableViewController 在具有有效数据的 reloadData 上导致 NSRangeException

Question

所以我在重新加载 tableView 时遇到了这个奇怪的崩溃。当类别数组为空时它加载正常，但是一旦我向数组添加值，我就会在重新加载 tableView 时收到 NSRangeException。即使数组中有 40 多个项目，它也会在索引 3 处崩溃。

public class CategorySearchMasterViewController: UITableViewController {

    private let reuseIdentifier = "category_cell"

    public weak var categoryDelegate: CategorySearchMasterViewControllerDelegate?
    public var categoryDrilldownRequest: CategoryDrilldownRequest?

    private var categories: [DrilldownCategory] = []

    public override func viewDidLoad() {
        super.viewDidLoad()

        categoryDrilldownRequest?.fetchCategories(callback: { [weak self] (payload) in
            self?.didReceivePayload(payload: payload)
        })
    }

    private func didReceivePayload(payload: DrilldownPayload) {
        categories = payload.categoriesList
        categoryDelegate?.categorySearchMasterViewControllerDidReceiveSymbols(symbols: payload.symbolList)
        tableView.reloadData()
    }

    public override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return categories.count
    }

    public override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        var cell = tableView.dequeueReusableCell(withIdentifier: reuseIdentifier)
        if cell == nil {
            cell = UITableViewCell(style: .default, reuseIdentifier: reuseIdentifier)
        }
        cell?.textLabel?.text = categories[indexPath.row].name
        cell?.accessoryType = .disclosureIndicator
        return cell!
    }

    public override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let masterView = segue.destination as? CategorySearchMasterViewController {
            masterView.categoryDrilldownRequest = categoryDrilldownRequest
        }
    }
}

堆栈跟踪:

2016-10-31 10:50:33.902 ProphetX[10884:12561505] \*** Terminating app due to uncaught exception 'NSRangeException', reason: '\*** -[\__NSArrayI objectAtIndex:]: index 3 beyond bounds [0 .. 2]'
\*** First throw call stack:
(
0   CoreFoundation                      0x012a8212 __exceptionPreprocess + 194
1   libobjc.A.dylib                     0x02a4ae66 objc_exception_throw + 52
2   CoreFoundation                      0x011dc666 -[__NSArrayI objectAtIndex:] + 198
3   UIKit                               0x03e1f5d2 -[UITableViewDataSource tableView:heightForRowAtIndexPath:] + 196
4   UIKit                               0x03a35778 -[UITableViewController tableView:heightForRowAtIndexPath:] + 75
5   UIKit                               0x0374ca37 -[UITableView _dataSourceHeightForRowAtIndexPath:] + 101
6   UIKit                               0x039bbb39 __66-[UISectionRowData refreshWithSection:tableView:tableViewRowData:]_block_invoke + 456
7   UIKit                               0x039bae21 -[UISectionRowData refreshWithSection:tableView:tableViewRowData:] + 4048
8   UIKit                               0x039beefe -[UITableViewRowData numberOfRows] + 85
9   UIKit                               0x037255c2 -[UITableView noteNumberOfRowsChanged] + 130
10  UIKit                               0x03724ae6 -[UITableView reloadData] + 2071
11  ProphetX                            0x0010962c _TFC8ProphetX34CategorySearchMasterViewControllerP33_1368510FCA7EF87AA17E4AFE1FCC1BF117didReceivePayloadfT7payloadVS_16DrilldownPayload_T_ + 1884
12  ProphetX                            0x00108e48 _TFFC8ProphetX34CategorySearchMasterViewController11viewDidLoadFT_T_U_FVS_16DrilldownPayloadT_ + 152
13  ProphetX                            0x0008762c _TFFC8ProphetX24CategoryDrilldownRequest15fetchCategoriesFT8callbackFVS_16DrilldownPayloadT__T_U_FGV9Alamofire12DataResponseSS_T_ + 844
14  ProphetX                            0x0008779a _TPA__TFFC8ProphetX24CategoryDrilldownRequest15fetchCategoriesFT8callbackFVS_16DrilldownPayloadT__T_U_FGV9Alamofire12DataResponseSS_T_ + 74
15  Alamofire                           0x00c107c6 _TTRXFo_oGV9Alamofire12DataResponseSS___XFo_iGS0_SS___ + 198
16  Alamofire                           0x00c1087a _TPA__TTRXFo_oGV9Alamofire12DataResponseSS___XFo_iGS0_SS___ + 74
17  Alamofire                           0x00c0c5c2 _TFFFC9Alamofire11DataRequest8responseuRxS_30DataResponseSerializerProtocolrFT5queueGSqCSo13DispatchQueue_18responseSerializerx17completionHandlerFGVS_12DataResponsewx16SerializedObject_T__DS0_U_FT_T_U_FT_T_ + 738
18  Alamofire                           0x00c14c42 _TPA__TFFFC9Alamofire11DataRequest8responseuRxS_30DataResponseSerializerProtocolrFT5queueGSqCSo13DispatchQueue_18responseSerializerx17completionHandlerFGVS_12DataResponsewx16SerializedObject_T__DS0_U_FT_T_U_FT_T_ + 114
19  Alamofire                           0x00c0c628 _TTRgRx9Alamofire30DataResponseSerializerProtocolrXFo___XFdCb___ + 40
20  libdispatch.dylib                   0x056b73ee _dispatch_call_block_and_release + 15
21  libdispatch.dylib                   0x056e2cc3 _dispatch_client_callout + 14
22  libdispatch.dylib                   0x056c20ef _dispatch_main_queue_callback_4CF + 1755
23  CoreFoundation                      0x0126878e __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 14
24  CoreFoundation                      0x0122b72f __CFRunLoopRun + 2319
25  CoreFoundation                      0x0122abab CFRunLoopRunSpecific + 395
26  CoreFoundation                      0x0122aa0b CFRunLoopRunInMode + 123
27  GraphicsServices                    0x06891b4c GSEventRunModal + 177
28  GraphicsServices                    0x068919c7 GSEventRun + 80
29  UIKit                               0x035ae32b UIApplicationMain + 148
30  ProphetX                            0x000f7351 main + 145
31  libdyld.dylib                       0x0571d799 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

Answer 1

所以它似乎与 UITableViewController 的 objc 实现如何解释 Swift 数组有关。

如果我重写 heightForRowAtIndexPath 和 indentationLevelForRowAtIndexPath，那么一切正常，但如果我保留任一方法的默认实现，它就会崩溃。

为了布局的灵 active ，我最终选择了带有 UITableView 元素的普通 UIViewController。增加的副作用是没有默认实现可以崩溃。