Swift 获取位置然后加载 table

Question

所以我想在用户第一次打开应用程序时询问他们的位置，然后加载 table。这是我现在的代码：

class LayoutController: UICollectionViewController, UICollectionViewDataSource,
UICollectionViewDelegate, UICollectionViewDelegateFlowLayout, 
APIControllerProtocol, CLLocationManagerDelegate {


    @IBOutlet weak var chainTable: UICollectionView!
    @IBOutlet weak var navLogo: UIButton!
    let locationManager : CLLocationManager = CLLocationManager()

    var lat: String = "lat!"
    var long: String = "long!"


    override func viewDidLoad() {
        super.viewDidLoad()
        UIApplication.sharedApplication().statusBarStyle = .LightContent
        navLogo.userInteractionEnabled = false

        self.locationManager.delegate = self
        self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
        self.locationManager.requestWhenInUseAuthorization()
        self.locationManager.startUpdatingLocation()
        if( CLLocationManager.authorizationStatus() == CLAuthorizationStatus.AuthorizedWhenInUse || CLLocationManager.authorizationStatus() == CLAuthorizationStatus.AuthorizedAlways){
            var currentLocation = locationManager.location
            var longitude = currentLocation.coordinate.longitude
            var latitude = currentLocation.coordinate.latitude

            long = String(stringInterpolationSegment: longitude)
            lat = String(stringInterpolationSegment: latitude)
        }
        // Do any additional setup after loading the view.            
        loadTable(lat, longitude, long)
    }

    func loadTable(latitude: String, longitude: String){
        api = APIController(delegate: self)
        UIApplication.sharedApplication().networkActivityIndicatorVisible = true
        api!.getPosts(latitude, longitude: longitude)
    }
}

首次下载和启用位置后数据未正确加载。但是，当您重新启动应用程序时，我确实可以工作。如何让 table 在加载前检查位置是否已给出？谢谢

（我已经尝试在 if CLLocationManager.authorizationstatus()... 块中使用 loadTable 函数，但也无济于事。）

Answer 1

需要监听CLLocationManagerDelegate的委托方法：

locationManager:didUpdateLocations:

在获得成功结果后，设置并重新加载 table 视图的数据。

Answer 2

正如@dimpiax 所暗示的那样，您的做法是错误的。

位置管理器是异步的API。一旦你确定你被授权使用它，你就要求它开始更新你的位置。然后你等待它调用你的委托方法 locationManager:didUpdateLocations:.

即使那样你还没有完成。通常你得到的第一个位置是旧的，而且非常非常错误。（这是 GPS 上次激活时读取的位置。）您必须检查该位置的时间戳，如果时间戳超过几秒则忽略它。

但是等等，您仍然没有完成。一旦你放弃了一个可能过时的位置，你需要等到 GPS 稳定下来并开始提供合适的读数。在您请求位置更新后的前 5 秒或更长时间，读数的误差范围通常非常糟糕。您可以通过检查您获得的位置记录上的水平精度属性来解决这个问题。该值实际上是一个半径。大数字不好，小数字好。您可能需要水平精度 <= 100 米的读数。

完成后，您就可以重新加载 table 视图了。

Answer 3

多亏了 Duncan 和 this tutorial

我弄明白了

func locationManager（管理器：CLLocationManager！，didUpdateLocations 位置：[AnyObject]！）{

    CLGeocoder().reverseGeocodeLocation(manager.location, completionHandler: { (placemarks, error) -> Void in

        if (error != nil){
            println("Error:" + error.localizedDescription)
        }

        if placemarks.count > 0 {
            let pm = placemarks[0] as! CLPlacemark

            if( CLLocationManager.authorizationStatus() == CLAuthorizationStatus.AuthorizedWhenInUse || CLLocationManager.authorizationStatus() == CLAuthorizationStatus.AuthorizedAlways){
                var currentLocation = self.locationManager.location
                var longitude = currentLocation.coordinate.longitude
                var latitude = currentLocation.coordinate.latitude

                self.long = String(stringInterpolationSegment: longitude)
                self.lat = String(stringInterpolationSegment: latitude)
            }

            self.displayLocationInfo(pm)
            self.loadTable(self.lat, longitude: self.long)
        }else{
            println("error with data")
        }

    })

我将其添加到 viewDidLoad 的正下方，并将 Auth 块移入其中。

Answer 4

我创建了一个 class 来获取用户的当前位置并 return 它在一个块中。

class NACurrentLocationTrackManager: NSObject,CLLocationManagerDelegate {
    var locationManager: CLLocationManager?
     private static var privateShared : NACurrentLocationTrackManager?
    typealias completionHandler = (_ location: CLLocation?,_ error: String?) -> Void
    var completion: completionHandler?
    class func shared() -> NACurrentLocationTrackManager {
    guard let uwShared = privateShared else {
        privateShared = NACurrentLocationTrackManager()
        return privateShared!
    }
    return uwShared
}
class func destroy() {
    privateShared = nil
}
func stopLocationManager() {
    locationManager?.stopUpdatingLocation()
}
func startMonitoringLocationWithBlock(handler:@escaping (_ location: CLLocation?,_ error: String?) -> Void){
    self.completion = handler
    if locationManager == nil{
        locationManager = CLLocationManager()
        locationManager?.delegate = self
        locationManager?.desiredAccuracy = kCLLocationAccuracyBest
        locationManager?.requestAlwaysAuthorization()
    }
    locationManager?.stopUpdatingLocation()
    locationManager?.startUpdatingLocation()
}
func restartMonitoringLocation(){
    locationManager?.stopUpdatingLocation()
    if CLLocationManager.authorizationStatus() == .authorizedAlways ||  CLLocationManager.authorizationStatus() == .authorizedWhenInUse{
        locationManager?.startUpdatingLocation()
    }else if CLLocationManager.authorizationStatus() == .denied{
        logh("Location service is disable")
        NAAppHelper.showLocationPermissionAlert()
        locationManager?.requestAlwaysAuthorization()
    }else{
        locationManager?.requestAlwaysAuthorization()
    }
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]){
    let location = locations.last
    if let handler = completion {
        handler(location, nil)
    }
    stopLocationManager()
}
    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        if let handler = completion {
            handler(nil, "")
        }
    }
 }
And to fetch the location, use this code in your viewcontroller:
    NACurrentLocationTrackManager.shared().startMonitoringLocationWithBlock { (location, error) in
        if error == nil {
            print(location)
        }
    }

Swift 获取位置然后加载 table

Swift get location THEN load table

cllocationmanager

cllocation

uicollectionview

uicollectionviewcell

swift