swift - UITable下拉刷新崩溃应用

Question

一切似乎都能正确加载，但是当我在我的应用程序中下拉我的表格 View 时它崩溃了，我不知道为什么。我是否遗漏了一段代码？

这是我的 viewController 代码:

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

设置刷新控制:

        self.refreshControl.attributedTitle = NSAttributedString(string: "Pull to refresh")
        self.refreshControl.addTarget(self, action: Selector(("refresh:")), for: UIControlEvents.valueChanged)
        self.partyTable?.addSubview(refreshControl)

        let ref = FIRDatabase.database().reference()

        // go to firebase and get all the parties and all there info
        ref.child("parties").queryOrderedByKey().observe(.childAdded, with: {
            snapshot in
            let snapshotValue = snapshot.value as? NSDictionary
            let name = snapshotValue?["name"] as! String
            let location = snapshotValue?["location"] as! String
            let description = snapshotValue?["description"] as! String
            let upVotes = snapshotValue?["upVotes"] as! String
            let downVotes = snapshotValue?["downVotes"] as! String

            self.parties.append(party(name: name, description: description, location: location, upVotes: Int(upVotes)!, downVotes: Int(downVotes)!))

            // update the table view to the all the parties
            DispatchQueue.main.async {
                self.refreshTableData()
            }
        })

    }

    // refreshes the table data when called
    func refreshTableData(){
        // go thru all the parties ansd sort them from postive to negative total votes
        for i in (0 ..< self.parties.count) {
            let total = self.parties[i].upVotes - self.parties[i].downVotes
            if i != 0{
                let oldTotal = self.parties[i-1].upVotes - self.parties[i-1].downVotes
                if total > oldTotal {
                    let savedParty = self.parties[i]
                    self.parties.remove(at: i)
                    self.parties.insert(savedParty, at:i-1)
                }
            }
        }

        self.partyTable?.reloadData()
    }

    // refreshes the table data when the table is pulled down
    func refresh(sender:AnyObject) {
        print("REFRESHED")
        refreshTableData()
    }

表格设置:

    // 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")

        let nameLabel = cell?.viewWithTag(1) as! UILabel
        nameLabel.text = parties[indexPath.row].name

        let locationLabel = cell?.viewWithTag(2) as! UILabel
        locationLabel.text = parties[indexPath.row].location

        let totalVotesLabel = cell?.viewWithTag(3) as! UILabel
        totalVotesLabel.text = (String(parties[indexPath.row].upVotes - parties[indexPath.row].downVotes))

        return cell!
    }

}

更新:

我得到的错误信息:

2016-11-07 19:00:58.625 Lit[6530:1248106] -[Lit.FindPartiesViewController refresh:]: unrecognized selector sent to instance 0x7fe618d2e230
2016-11-07 19:00:58.638 Lit[6530:1248106] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Lit.FindPartiesViewController refresh:]: unrecognized selector sent to instance 0x7fe618d2e230'
*** First throw call stack:
(
    0   CoreFoundation                      0x000000010e82634b __exceptionPreprocess + 171
    1   libobjc.A.dylib                     0x000000010e28721e objc_exception_throw + 48
    2   CoreFoundation                      0x000000010e895f34 -[NSObject(NSObject) doesNotRecognizeSelector:] + 132
    3   CoreFoundation                      0x000000010e7abc15 ___forwarding___ + 1013
    4   CoreFoundation                      0x000000010e7ab798 _CF_forwarding_prep_0 + 120
    5   UIKit                               0x000000010ec4bb88 -[UIApplication sendAction:to:from:forEvent:] + 83
    6   UIKit                               0x000000010edd12b2 -[UIControl sendAction:to:forEvent:] + 67
    7   UIKit                               0x000000010edd15cb -[UIControl _sendActionsForEvents:withEvent:] + 444
    8   UIKit                               0x000000010f6e9dac -[UIRefreshControl _setRefreshControlState:notify:] + 525
    9   UIKit                               0x000000010f6f2231 -[_UIRefreshControlModernContentView _snappingMagic] + 53
    10  UIKit                               0x000000010f6f0c70 -[_UIRefreshControlModernContentView didTransitionFromState:toState:] + 205
    11  UIKit                               0x000000010f6e9d3d -[UIRefreshControl _setRefreshControlState:notify:] + 414
    12  UIKit                               0x000000010f6e8b18 -[UIRefreshControl _setVisibleHeight:] + 71
    13  UIKit                               0x000000010f6e91ea -[UIRefreshControl _update] + 374
    14  UIKit                               0x000000010ed33f5a -[UIScrollView(UIScrollViewInternal) _notifyDidScroll] + 174
    15  UIKit                               0x000000010ed1e919 -[UIScrollView setContentOffset:] + 478
    16  UIKit                               0x000000010eda96b7 -[UITableView setContentOffset:] + 316
    17  UIKit                               0x000000010ed23351 -[UIScrollView _updatePanGesture] + 2346
    18  UIKit                               0x000000010f18c289 -[UIGestureRecognizerTarget _sendActionWithGestureRecognizer:] + 57
    19  UIKit                               0x000000010f194028 _UIGestureRecognizerSendTargetActions + 109
    20  UIKit                               0x000000010f191af7 _UIGestureRecognizerSendActions + 227
    21  UIKit                               0x000000010f190d83 -[UIGestureRecognizer _updateGestureWithEvent:buttonEvent:] + 891
    22  UIKit                               0x000000010f17ce56 _UIGestureEnvironmentUpdate + 1395
    23  UIKit                               0x000000010f17c89b -[UIGestureEnvironment _deliverEvent:toGestureRecognizers:usingBlock:] + 521
    24  UIKit                               0x000000010f17ba7e -[UIGestureEnvironment _updateGesturesForEvent:window:] + 286
    25  UIKit                               0x000000010ecba7ad -[UIWindow sendEvent:] + 3989
    26  UIKit                               0x000000010ec67a33 -[UIApplication sendEvent:] + 371
    27  UIKit                               0x000000010f459b6d __dispatchPreprocessedEventFromEventQueue + 3248
    28  UIKit                               0x000000010f452817 __handleEventQueue + 4879
    29  CoreFoundation                      0x000000010e7cb311 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
    30  CoreFoundation                      0x000000010e7b059c __CFRunLoopDoSources0 + 556
    31  CoreFoundation                      0x000000010e7afa86 __CFRunLoopRun + 918
    32  CoreFoundation                      0x000000010e7af494 CFRunLoopRunSpecific + 420
    33  GraphicsServices                    0x00000001121afa6f GSEventRunModal + 161
    34  UIKit                               0x000000010ec49f34 UIApplicationMain + 159
    35  Lit                                 0x000000010c419b3f main + 111
    36  libdyld.dylib                       0x0000000110e6d68d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb) 

Answer 1

由于您没有使用发件人，只需将其删除即可。

func refresh() {
     print("REFRESHED")
     refreshControl?.endRefreshing()
     refreshTableData()
}

然后在将目标添加到刷新控件时，不要在 refresh 选择器之后使用 :(因为您删除了 sender 参数)。

同样通过使用#selector(refresh)而不是Selector("refresh")，您将在编译前知道选择器是否被识别。

self.refreshControl.addTarget(self, action: #selector(refresh), for: .valueChanged)