iOS 模拟器和 reverseGeocodeLocation

Question

关于抓取位置，iOS 模拟器经常不工作是否正常？每当我运行模拟器时，这个应用程序的项目都会在 50% 的时间内崩溃……但我似乎无法在代码本身中查明问题。如果问题确实出在代码本身，谁能帮我找到问题所在？错误是“ fatal error :在展开可选值时意外发现 nil”，它说它发生在我的 refreshPost 函数中

eventsPostedQuery.whereKey("CityName", equalTo: self.usersLocation)

我将 Parse 用作此应用程序的一部分。另外，我有一个 viewDidAppear 来刷新“帖子”，这是解决这个问题的正确方法吗？非常感谢!

import UIKit
import Parse

class HomeTableViewController: UITableViewController, CLLocationManagerDelegate {

@IBOutlet weak var navigationBar: UINavigationItem!
@IBOutlet weak var menuButton: UIBarButtonItem!

@IBAction func cancelPost(segue: UIStoryboardSegue) {

}

var users = [String: String]()
var usernames = [String]()
var eventInfo = [String]()
var imageFiles = [PFFile]()
var usersLocation: String!

var locationManager: CLLocationManager!

func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

    let userLocation: CLLocation = locations[0]


    CLGeocoder().reverseGeocodeLocation(userLocation) { (placemarks, error) -> Void in

        if error != nil {

            print(error)

        } else {

            let p = placemarks?.first // ".first" returns the first element in the collection, or nil if its empty
            // this code above will equal the first element in the placemarks array

            let city = p?.locality != nil ? p?.locality : ""
            let state = p?.administrativeArea != nil ? p?.administrativeArea : ""

            self.navigationBar.title = ("\(city!), \(state!)")
            self.usersLocation = ("\(city!), \(state!)")
            self.locationManager.stopUpdatingLocation()
            print(self.usersLocation)
        }
    }
}

override func viewDidLoad() {
    super.viewDidLoad()

    locationManager = CLLocationManager()
    locationManager.delegate = self
    locationManager.desiredAccuracy = kCLLocationAccuracyBest
    locationManager.requestWhenInUseAuthorization()
    locationManager.startUpdatingLocation()

    menuButton.target = self.revealViewController()
    menuButton.action = Selector("revealToggle:")

    self.view.addGestureRecognizer(self.revealViewController().panGestureRecognizer())

    self.tableView.rowHeight = UITableViewAutomaticDimension
    self.tableView.estimatedRowHeight = 250.0
}

override func viewDidAppear(animated: Bool) {

    refreshPosts()

}


func refreshPosts() {

    let query = PFUser.query()
    query?.findObjectsInBackgroundWithBlock({ (objects, error) -> Void in

        if let users = objects {

            self.users.removeAll(keepCapacity: true)
            self.usernames.removeAll(keepCapacity: true)
            self.eventInfo.removeAll(keepCapacity: true)
            self.imageFiles.removeAll(keepCapacity: true)

            for object in users {

                if let user = object as? PFUser {

                    self.users[user.objectId!] = user.username!

                }
            }
        }

    let eventsPostedQuery = PFQuery(className: "PostEvent")
    eventsPostedQuery.whereKey("CityName", equalTo: self.usersLocation)
    eventsPostedQuery.orderByDescending("createdAt")
    eventsPostedQuery.findObjectsInBackgroundWithBlock({ (objects, error) -> Void in

        if let events = objects {
            for event in events {
                self.imageFiles.append(event["imageFile"] as! PFFile)
                self.eventInfo.append(event["eventInfo"] as! String)
                self.usernames.append(self.users[event["userId"] as! String]!)

                self.tableView.reloadData()

                }
            }

        })

    })


}

Answer 1

你应该打电话

refreshPosts()

从这个完成 block 的 else block 内部:

CLGeocoder().reverseGeocodeLocation(userLocation) { (placemarks, error) -> Void in

    if error != nil {

        print(error)

    } else {

        let p = placemarks?.first // ".first" returns the first element in the collection, or nil if its empty
        // this code above will equal the first element in the placemarks array

        let city = p?.locality != nil ? p?.locality : ""
        let state = p?.administrativeArea != nil ? p?.administrativeArea : ""

        self.navigationBar.title = ("\(city!), \(state!)")
        self.usersLocation = ("\(city!), \(state!)")
        self.locationManager.stopUpdatingLocation()
        print(self.usersLocation)
    }
}

如仅在反向地理编码器完成且未返回错误时更新帖子。