ios - 发送到 instance-Swift 的无法识别的选择器

Question

大家好:我有一个函数可以点击 API 下载数据(LAT，LONG)并且它可以 100% 正常工作。但问题是我想每 5 秒调用一次这个函数，在我添加一个计时器来执行此操作后，每次我尝试运行它时它运行得非常好，5 秒后我崩溃了

unrecognized selector sent to instance 0x7ffa4a51cb00
2018-07-20 11:05:31.191467+0200 Interactive Bus[684:6752] *** 
Terminating app due to uncaught exception 'NSInvalidArgumentException', 
reason: '-[Interactive_Bus.MapVC 
downloadBusDataWithUserId:warning:delegate:completed:]: unrecognized 
selector sent to instance 0x7ffa4a51cb00'

我尝试清理然后构建并且没有代码错误我不知道为什么会发生这种崩溃

这是我的模型类

//  busLocationModel.swift
//  Interactive Bus
import UIKit
import Alamofire
import SwiftyJSON

class busLocationModel {

var route_pins: String?
var busLatitude: Double?
var busLongitude: Double?

@objc func downloadBusData(userId: String,warning: @escaping (String,String,String) -> Void, delegate : MapVC ,completed : @escaping DownloadCompleted) {

    let Parameters = ["parent_id": userId]
    print(#function)
    Alamofire.request(busLocationUrl, method: .get, parameters: Parameters).responseJSON { (response) in

        switch response.result {

        case .failure(let error):

            print(error)

            let alertControllerTitle = "Warning"
            let actionButtonTitle = "Ok"
            let alertMessage = "Some Thing Went Wrong Please Try Agin Later "

            return warning(alertControllerTitle, actionButtonTitle, alertMessage)

        case .success(let Value):

            let json = JSON(Value)
            //print(json)

            let status = json["status"].boolValue

            if status != false {

                for locations in json["data"].arrayValue {

                    let busPins = locations["route_pins"].stringValue
                    let bus_lat = locations["bus_lat"].doubleValue
                    let bus_long = locations["bus_long"].doubleValue

                    delegate.busPins = busPins
                    delegate.currentBusLate = bus_lat
                    delegate.currentBusLong = bus_long

                    print(delegate.busPins ?? "HH")
                    print("the bus lat is \(bus_lat)")
                    print("the bus long is \(bus_long)")
                }

            }
        }
        completed()
    }
}
}

我的常量是:

typealias DownloadCompleted = () -> ()

我的 MapVC 是:

//
import UIKit
import MapKit
import CoreLocation

class MapVC: UIViewController {

@IBOutlet weak private var busMapView: MKMapView!

var locationManager = CLLocationManager()
//var locationManager: CLLocationManager!
let authorizationStatus = CLLocationManager.authorizationStatus()
fileprivate let regionRadius: Double = 1000 //Meter's From UP,Right,Down and Left
fileprivate var busInfoObject: busLocationModel!

var busPins: String!
var currentBusLate: CLLocationDegrees?
var currentBusLong: CLLocationDegrees?

var callFuncTimer: Timer!



override func viewDidLoad() {
    super.viewDidLoad()

    locationManager.delegate = self
    busMapView.delegate = self
    busInfoObject = busLocationModel()

    let myActivity = CreatActivityIndicator()


    busInfoObject.downloadBusData(userId: "366", warning: DisplayAlertMessage, delegate: self) {

        self.drawLine()
        self.RemoveActivityIndicator(ActivityIndicator: myActivity)

        guard let latitude = self.currentBusLate else { return }
        guard let longitude = self.currentBusLong else { return }

        let Location = CLLocation(latitude: latitude, longitude: longitude)

        self.centerMapOnBusLocation(location: Location)

        self.callFuncTimer = Timer.scheduledTimer(timeInterval: 5, target: self, selector: #selector(self.busInfoObject.downloadBusData(userId:warning:delegate:completed:)), userInfo: nil, repeats: true)

    }
}

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(true)

    configureLocationServices()
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(true)

    callFuncTimer.invalidate()
}

@IBAction func centerMapBtnPressed(_ sender: Any) {

    if authorizationStatus == .authorizedAlways {

        guard let latitude = self.currentBusLate else { return }
        guard let longitude = self.currentBusLong else { return }

        let Location = CLLocation(latitude: latitude, longitude: longitude)

        centerMapOnBusLocation(location: Location)
    }
}
}
extension MapVC: MKMapViewDelegate {

fileprivate func centerMapOnBusLocation(location: CLLocation) {

    //guard let currtntLocationCoordinate = locationManager.location?.coordinate else { return }
    let coordinateRegion = MKCoordinateRegionMakeWithDistance(location.coordinate , regionRadius * 2.0, regionRadius * 2.0)
    busMapView.setRegion(coordinateRegion, animated: true)
}


func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {

    if (overlay is MKPolyline) {
        let pr = MKPolylineRenderer(overlay: overlay)
        pr.strokeColor = UIColor.blue
        pr.lineWidth = 5
        return pr
    }
    return MKPolylineRenderer()
}
}

extension MapVC {

func drawLine() {

    let coordinates = busPins.components(separatedBy: "#").dropFirst().map { (pin) -> CLLocationCoordinate2D in
        let latLng = pin.components(separatedBy: ",").map{ CLLocationDegrees($0)! }
        return CLLocationCoordinate2D(latitude: latLng[0], longitude: latLng[1])
    }

    let polyLine = MKPolyline(coordinates: coordinates , count: coordinates.count)
    self.busMapView.add(polyLine)
}

}

extension MapVC: CLLocationManagerDelegate {

fileprivate func configureLocationServices() {

    if authorizationStatus == .notDetermined {
        locationManager.requestAlwaysAuthorization()
    } else {

        return
    }
}

func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {

    guard let latitude = self.currentBusLate else { return }
    guard let longitude = self.currentBusLong else { return }

    let Location = CLLocation(latitude: latitude, longitude: longitude)

    centerMapOnBusLocation(location: Location)
}
}

这是 DisplayAlertMessage:

    func DisplayAlertMessage(alertControllerTitle: String , actionButtonTitle: String , alertMessage: String) -> Void{


    let alertcontroller = UIAlertController(title: alertControllerTitle, message: alertMessage , preferredStyle: .alert)

    let okaction = UIAlertAction(title: actionButtonTitle, style: .default, handler: nil)

    alertcontroller.addAction(okaction)
    self.present(alertcontroller, animated: true, completion: nil)
}

我看不到任何代码错误我执行@OBJC选择器语法是正确的但我仍然得到错误(无法识别的选择器发送到实例)你能帮我解决这个问题吗？？

Answer 1

在目标- Action 模式中，目标对象需要实现 Action 方法。

但是在你的代码中:

self.callFuncTimer = Timer.scheduledTimer(timeInterval: 5, target: self, selector: #selector(self.busInfoObject.downloadBusData(userId:warning:delegate:completed:)), userInfo: nil, repeats: true)

您使用 self 作为目标，它是 MapVC 的一个实例，它没有实现方法 downloadBusData(userId:warning:delegate:completed:) 。

当您为操作方法指定#selector(someInstance.methodName(...)) 时，您需要将someInstance 传递给目标对象。在你的例子中 someInstance 是 self.busInfoObject。

这意味着创建 Timer 的行应该像这样:

self.callFuncTimer = Timer.scheduledTimer(timeInterval: 5, target: self.busInfoObject, selector: #selector(self.busInfoObject.downloadBusData(userId:warning:delegate:completed:)), userInfo: nil, repeats: true)

但这行不通。

---

我太蠢了，差点忘了告诉你目标- Action 模式中的另一件重要事情。

也就是

action 方法的签名是根据目标确定的。

使用 Timer 时，签名需要与此相同:

class func scheduledTimer(timeInterval: TimeInterval, target: Any, selector: Selector, userInfo: Any?, repeats: Bool) -> Timer

- (void)timerFireMethod:(NSTimer *)timer

符号是 Objective-C 格式，但是 Timer 的操作方法需要有一个且只有一个 Timer 类型的参数(它是 NSTimer 在 Objective-C 中。)

因此，您可能需要定义一个与 MapVC 中的签名相匹配的方法:

func timerFired(_ timer: Timer) {
    self.busInfoObject.downloadBusData(userId: ...,
                                       warning: {_, _, _ in
                                           ...
                                       }, 
                                       delegate: self,
                                       completed: {
                                           ...
                                       })
}

并将设置计时器的行更改为:

self.callFuncTimer = Timer.scheduledTimer(timeInterval: 5, target: self, selector: #selector(self.timerFired(_:)), userInfo: nil, repeats: true)

抱歉，给你一个不完整的答案，请尝试在我更新的代码中填充 ...。