如何解决 Swift 中的 [NSArray0 objectAtIndex:] 错误？ [关闭]答案

【问题标题】：How can I solve [NSArray0 objectAtIndex:] error in Swift? [closed]如何解决 Swift 中的 [NSArray0 objectAtIndex:] 错误？ [关闭]
【发布时间】：2020-11-28 19:30:09
【问题描述】：

单击我的 swift 应用程序以跟踪驱动程序位置时，我收到上述错误。本质上，它显示了司机的位置，但未能绘制司机和酒店/客户之间的路径。该应用程序冻结并引发上述错误。希望有人能帮我解决这个问题。

func makePath(){
    self.mapView.clear()
    var bounds = GMSCoordinateBounds()
    self.mapView.camera = GMSCameraPosition.camera(withLatitude: (self.riderlat as NSString).doubleValue, longitude: (self.riderlong as! NSString).doubleValue, zoom: 1.0)
    self.riderMarker.title = StaticData.singleton.map_name
    self.riderMarker.snippet = StaticData.singleton.map_phone

    let str :String?
    if (self.riderlat == "0.0" || self.riderlong == "0.0" || self.hotellat == "0.0" || self.hotellong == "0.0" ) {
        str = ""
    } else {
        str = String(format:"https://maps.googleapis.com/maps/api/directions/json?origin=\(self.riderlat!),\(self.riderlong!)&destination=\(self.hotellat!),\(self.hotellong!)&key=AIzaSyBEDFKSDFKDSFNSDKF9434-0")
        
        //print(str!)
    }
    
    Alamofire.request(str!).responseJSON { (responseObject) -> Void in
        let resJson = JSON(responseObject.result.value)
        //print(resJson)
        
        if(resJson["status"].rawString()! == "ZERO_RESULTS") {
            
        } else if(resJson["status"].rawString()! == "NOT_FOUND") {
            
        } else {
            if  let routes : NSArray = resJson["routes"].rawValue as? NSArray {
                //print(routes)

                self.mapView.isMyLocationEnabled = true
                let position = CLLocationCoordinate2D(latitude:(self.riderlat as NSString).doubleValue, longitude: (self.riderlong as NSString).doubleValue)

                let marker = GMSMarker(position: position)

                marker.icon = UIImage(named: "Car.png")
                marker.title = "Customer have selected same location as yours"
                marker.map = self.mapView
                bounds = bounds.includingCoordinate(marker.position)

                let position2 = CLLocationCoordinate2D(latitude:(self.hotellat as NSString).doubleValue, longitude: (self.hotellong as NSString).doubleValue )

                let marker1 = GMSMarker(position: position2)
                marker1.icon = UIImage(named: "HotelPin")
                marker1.appearAnimation = GMSMarkerAnimation.pop
                marker1.map = self.mapView
                self.riderMarker.icon = UIImage(named:"Car.png")
                self.riderMarker.map = self.mapView
                self.getAddressFromLatLon(pdblLatitude:StaticData.singleton.rider_lat!, withLongitude:StaticData.singleton.rider_lon!)

                for p in (0 ..< self.polyArray.count) {
                    (self.polyArray[p]).map = nil
                }
                let pathv : NSArray = routes.value(forKey: "overview_polyline") as! NSArray
                //print(pathv)
                let paths : NSArray = pathv.value(forKey: "points") as! NSArray
                //print(paths)

                let newPath = GMSPath.init(fromEncodedPath: paths[0] as! String)

                let polyLine = GMSPolyline(path: newPath)
                polyLine.strokeWidth = 5
                polyLine.strokeColor = UIColor(red:190/255.0, green:44/255.0, blue:44/255.0, alpha:1.0)
                self.polyArray.append(polyLine)
                polyLine.map = self.mapView
                self.polyArray.append(polyLine)
                let bounds = GMSCoordinateBounds(path: newPath!)
                self.mapView!.animate(with: GMSCameraUpdate.fit(bounds, withPadding: 50.0))
            }
        }
    }
}

尤其是错误指向的代码部分：

let newPath = GMSPath.init(fromEncodedPath: paths[0] as! String)

【问题讨论】：

错误信息很清楚不是吗？您尝试访问空数组中的元素。现在启动调试器并找出为什么数组是空的。

标签： swift google-maps swift4 google-places-api

【解决方案1】：

您的那行代码假设路径数组总是至少有一个元素。当路径为空时会出现此错误，因此您需要先检查数组是否为空：

let paths : NSArray = pathv.value(forKey: "points") as! NSArray
if (paths.count == 0) {
    // Do something depend on your business or return error
}
let newPath = GMSPath.init(fromEncodedPath: paths[0] as! String)

【讨论】：