Tableview简单显示值

Question

我是一名student，也是swift3的初学者。在这里，我只想在tableview中显示“First”，“Second”，“Third”，看起来不太好。

youtube 上的教程是 swift2，我尝试转换成 swift3。我认为问题与代码有关：

let Cell = self.tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as UITableViewCell

我努力搜索https://www.codeschool.com/blog/2016/09/14/evolving-to-swift-3/，但我不知道会发生什么。 Xcode 无法检测到代码的任何错误并且可以运行。 iphone模拟器中的tableview为空或全屏黑屏。

我使用导航控制器来实现它。 viewcontoller 中的 class 和 table view cell 中的 iderntifer 在根视图控制器中设置得很好。请帮我。谢谢。

import Foundation
import UIKit

class ViewController: UITableViewController {

var Array = [String]()

override func viewDidLoad() {
    super.viewDidLoad()

    Array = ["First","Second","Third"]

}

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

 override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let Cell = self.tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as UITableViewCell

    Cell.textLabel?.text = Array[indexPath.row]

    return Cell
}

}

控制台中的结果：

2016-10-24 01:10:38.111399 TableApp[27276:2609723] subsystem: com.apple.UIKit, category: HIDEventFiltered, enable_level: 0, persist_level: 0, default_ttl: 0, info_ttl: 0, debug_ttl: 0, generate_symptoms: 0, enable_oversize: 1, privacy_setting: 2, enable_private_data: 0
2016-10-24 01:10:38.114012 TableApp[27276:2609723] subsystem: com.apple.UIKit, category: HIDEventIncoming, enable_level: 0, persist_level: 0, default_ttl: 0, info_ttl: 0, debug_ttl: 0, generate_symptoms: 0, enable_oversize: 1, privacy_setting: 2, enable_private_data: 0
2016-10-24 01:10:38.122822 TableApp[27276:2609719] subsystem: com.apple.BaseBoard, category: MachPort, enable_level: 1, persist_level: 0, default_ttl: 0, info_ttl: 0, debug_ttl: 0, generate_symptoms: 0, enable_oversize: 0, privacy_setting: 0, enable_private_data: 0
2016-10-24 01:10:38.138706 TableApp[27276:2609660] subsystem: com.apple.UIKit, category: StatusBar, enable_level: 0, persist_level: 0, default_ttl: 0, info_ttl: 0, debug_ttl: 0, generate_symptoms: 0, enable_oversize: 1, privacy_setting: 2, enable_private_data: 0
2016-10-24 01:10:38.200 TableApp[27276:2609660] *** Assertion failure in -[UITableView _configureCellForDisplay:forIndexPath:], /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKit_Sim/UIKit-3599.6/UITableView.m:8035
2016-10-24 01:10:38.203 TableApp[27276:2609660] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'UITableView (<UITableView: 0x7fbac906bc00; frame = (0 0; 375 667); clipsToBounds = YES; autoresize = W+H; gestureRecognizers = <NSArray: 0x61000004e400>; layer = <CALayer: 0x610000235ce0>; contentOffset: {0, -64}; contentSize: {375, 132}>) failed to obtain a cell from its dataSource (<TableApp.GetStringViewController: 0x7fbac8d06180>)'
*** First throw call stack:
(
    0   CoreFoundation                      0x000000010fab034b __exceptionPreprocess + 171
    1   libobjc.A.dylib                     0x000000010c9dc21e objc_exception_throw + 48
    2   CoreFoundation                      0x000000010fab4442 +[NSException raise:format:arguments:] + 98
    3   Foundation                          0x000000010c572edd -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 195
    4   UIKit                               0x000000010d429ff2 -[UITableView _configureCellForDisplay:forIndexPath:] + 222
    5   UIKit                               0x000000010d435c10 -[UITableView _createPreparedCellForGlobalRow:withIndexPath:willDisplay:] + 860
    6   UIKit                               0x000000010d435e07 -[UITableView _createPreparedCellForGlobalRow:willDisplay:] + 74
    7   UIKit                               0x000000010d409871 -[UITableView _updateVisibleCellsNow:isRecursive:] + 3295
    8   UIKit                               0x000000010d43f189 -[UITableView _performWithCachedTraitCollection:] + 110
    9   UIKit                               0x000000010d4259e3 -[UITableView layoutSubviews] + 222
    10  UIKit                               0x000000010d38d344 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 1237
    11  QuartzCore                          0x0000000112875cdc -[CALayer layoutSublayers] + 146
    12  QuartzCore                          0x00000001128697a0 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 366
    13  QuartzCore                          0x000000011286961e _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 24
    14  QuartzCore                          0x00000001127f762c _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 280
    15  QuartzCore                          0x0000000112824713 _ZN2CA11Transaction6commitEv + 475
    16  QuartzCore                          0x0000000112825083 _ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 113
    17  CoreFoundation                      0x000000010fa54e17 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
    18  CoreFoundation                      0x000000010fa54d87 __CFRunLoopDoObservers + 391
    19  CoreFoundation                      0x000000010fa394b6 CFRunLoopRunSpecific + 454
    20  UIKit                               0x000000010d2c2db6 -[UIApplication _run] + 434
    21  UIKit                               0x000000010d2c8f34 UIApplicationMain + 159
    22  TableApp                            0x000000010c3fb5bf main + 111
    23  libdyld.dylib                       0x00000001109da68d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb) 

Answer 1

试试这个代码：在 Swift 3 中测试的代码。

注意：正如您提到的，您刚刚开始编写 Swift 3。我以编程方式创建了一个 tableView。只需复制下面的代码并粘贴到您的 viewController.run 项目...

    import UIKit

    class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

    private let MyArray: NSArray = ["First","Second","Third"]
    private var myTableView: UITableView!

    override func viewDidLoad() {
    super.viewDidLoad()

    // Status Bar 
    let barHeight: CGFloat = UIApplication.shared.statusBarFrame.size.height 

    // View 
    let displayWidth: CGFloat = self.view.frame.width
    let displayHeight: CGFloat = self.view.frame.height

    // TableView 
    myTableView = UITableView(frame: CGRect(x: 0, y: barHeight, width: displayWidth, height: displayHeight - barHeight))

    // Cell 
    myTableView.register(UITableViewCell.self, forCellReuseIdentifier: "MyCell")

    // DataSource 
    myTableView.dataSource = self

    // Delegate 
    myTableView.delegate = self

    // View 
    self.view.addSubview(myTableView)
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}


func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    print("Num: \(indexPath.row)")
    print("Value: \(MyArray[indexPath.row])")
}

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

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    let cell = tableView.dequeueReusableCell(withIdentifier: "MyCell", for: indexPath as IndexPath) 

    cell.textLabel!.text = "\(MyArray[indexPath.row])"

    return cell
 }

}

输出：