Question

我试图让我的应用程序有一个向上投票/向下投票系统类似reddit，这意味着我的表中的每个单元格在单击按钮时只需改变自己的数据就会有不同的反应。我创建了一个自定义单元格类并相应地设置了所有内容，但由于某些原因，当我运行我的应用程序时，它会在您按下单元格中的按钮时崩溃。

这是我的代码（我试图编辑掉任何不必要的部分，但如果你想看到整件事情，请告诉我）：

import UIKit
import Firebase
import FirebaseDatabase

class FindPartiesViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

    // where we will store all the parties
    var parties = [party]()

    @IBOutlet weak var partyTable: UITableView!

    var refreshControl = UIRefreshControl()

    override func viewDidLoad() {
        super.viewDidLoad()

        partyTable.delegate = self
        partyTable.dataSource = self       
    }



    // creates the number of cells in the table
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        return parties.count    

    // define all the cells
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        // Make table cells the show the party
        let cell = partyTable.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! CustomCell

       cell.nameLabel.text = parties[indexPath.row].name

       cell.LocationLabel.text = parties[indexPath.row].location

       cell.totalVotesLabel.text = (String(parties[indexPath.row].upVotes - parties[indexPath.row].downVotes))

       cell.upVoteButton.tag = indexPath.row
       cell.upVoteButton.addTarget(self, action: Selector(("upVoteAction")), for: .touchUpInside)
       cell.downVoteButton.tag = indexPath.row
       cell.downVoteButton.addTarget(self, action: Selector(("downVoteAction")), for: .touchUpInside)



        return cell
    }

    @IBAction func upVoteAction(sender: UIButton){

       print("+1")
       parties[sender.tag].upVotes = parties[sender.tag].upVotes + 1
    }

}

（UPDATE） 我的错误信息：

2016-11-10 13:35:20.371 Lit[16625:2721786] -[Lit.FindPartiesViewController upVoteAction]: unrecognized selector sent to instance 0x7fc40b420240
2016-11-10 13:35:20.375 Lit[16625:2721786] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Lit.FindPartiesViewController upVoteAction]: unrecognized selector sent to instance 0x7fc40b420240'
*** First throw call stack:
(
    0   CoreFoundation                      0x00000001093ef34b __exceptionPreprocess + 171
    1   libobjc.A.dylib                     0x0000000108e5021e objc_exception_throw + 48
    2   CoreFoundation                      0x000000010945ef34 -[NSObject(NSObject) doesNotRecognizeSelector:] + 132
    3   CoreFoundation                      0x0000000109374c15 ___forwarding___ + 1013
    4   CoreFoundation                      0x0000000109374798 _CF_forwarding_prep_0 + 120
    5   UIKit                               0x0000000109814b88 -[UIApplication sendAction:to:from:forEvent:] + 83
    6   UIKit                               0x000000010999a2b2 -[UIControl sendAction:to:forEvent:] + 67
    7   UIKit                               0x000000010999a5cb -[UIControl _sendActionsForEvents:withEvent:] + 444
    8   UIKit                               0x00000001099994c7 -[UIControl touchesEnded:withEvent:] + 668
    9   UIKit                               0x0000000109d4b1dc _UIGestureEnvironmentSortAndSendDelayedTouches + 5645
    10  UIKit                               0x0000000109d45ea3 _UIGestureEnvironmentUpdate + 1472
    11  UIKit                               0x0000000109d4589b -[UIGestureEnvironment _deliverEvent:toGestureRecognizers:usingBlock:] + 521
    12  UIKit                               0x0000000109d44a7e -[UIGestureEnvironment _updateGesturesForEvent:window:] + 286
    13  UIKit                               0x00000001098837ad -[UIWindow sendEvent:] + 3989
    14  UIKit                               0x0000000109830a33 -[UIApplication sendEvent:] + 371
    15  UIKit                               0x000000010a022b6d __dispatchPreprocessedEventFromEventQueue + 3248
    16  UIKit                               0x000000010a01b817 __handleEventQueue + 4879
    17  CoreFoundation                      0x0000000109394311 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
    18  CoreFoundation                      0x000000010937959c __CFRunLoopDoSources0 + 556
    19  CoreFoundation                      0x0000000109378a86 __CFRunLoopRun + 918
    20  CoreFoundation                      0x0000000109378494 CFRunLoopRunSpecific + 420
    21  GraphicsServices                    0x000000010cd78a6f GSEventRunModal + 161
    22  UIKit                               0x0000000109812f34 UIApplicationMain + 159
    23  Lit                                 0x0000000106fda27f main + 111
    24  libdyld.dylib                       0x000000010ba3668d start + 1
    25  ???                                 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)

Answer 1

Selector("upVoteAction")

和

func upVoteAction(sender: UIButton)

不相同，所以它根本找不到那个方法。您需要将前者的更改添加到

Selector("upVoteAction:")

因为您的实际方法有一个参数。

编辑根据@ rmaddy的评论，swift 3方式会是这样的：

#selector(upVoteAction(sender:))

Answer 2

首先，尝试说明控制台中打印的错误。

其次，确保所有IBoutlet都已连接，并且没有任何未连接的IBoutlet。如果其中一个插座周围有感叹号，请使用 x 按钮将其删除并重新构建。

Answer 3

您的单元格已经有自定义单元格类，因此我建议为该类中的按钮创建IBActions。在Interface Builder中，按住Ctrl键从按钮拖动到类文件，然后在那里定义操作。

这样您就不必将代码基于按钮的不同标记。

单击单元格按钮时应用程序崩溃

3 个答案: