objective-c 如何检索用户当前的城市名称？

How to retrieve user's current city name?

提问by Sandeep Kumar

How do you retrieve the user's current city name?

你如何检索用户当前的城市名称？

回答by Marc

As of iOS 5 MKReverseGeoCoderis Deprecated!

自 iOS 5 起MKReverseGeoCoder已弃用！

So you want to use CLGeocoderwith CLLocationManager, very simple and works with block.

所以你想使用CLGeocoderwith CLLocationManager，非常简单并且可以与块一起使用。

Example:

例子：

- (void)locationManager:(CLLocationManager *)manager
    didUpdateToLocation:(CLLocation *)newLocation
           fromLocation:(CLLocation *)oldLocation
{
   [self.locationManager stopUpdatingLocation];

   CLGeocoder * geoCoder = [[CLGeocoder alloc] init];
    [geoCoder reverseGeocodeLocation:newLocation
                   completionHandler:^(NSArray *placemarks, NSError *error) {
                       for (CLPlacemark *placemark in placemarks) {
                           .... = [placemark locality];
                       }
                   }];
}

Edit:Instead of a for inloop you can also do:

编辑：for in您还可以执行以下操作，而不是循环：

NSString *locString = placemarks.count ? [placemarks.firstObject locality] : @"Not Found";

回答by tony.tc.leung

What you have to do is setup a CLLocationManagerthat will find your current coordinates. With the current coordinates you need to use MKReverseGeoCoderto find your location.

你需要做的是设置一个CLLocationManager会找到你当前坐标的。使用您需要使用的当前坐标MKReverseGeoCoder来查找您的位置。

- (void)viewDidLoad 
{  
    // this creates the CCLocationManager that will find your current location
    CLLocationManager *locationManager = [[[CLLocationManager alloc] init] autorelease];
    locationManager.delegate = self;
    locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters;
    [locationManager startUpdatingLocation];
}

// this delegate is called when the app successfully finds your current location
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation 
{
    // this creates a MKReverseGeocoder to find a placemark using the found coordinates
    MKReverseGeocoder *geoCoder = [[MKReverseGeocoder alloc] initWithCoordinate:newLocation.coordinate];
    geoCoder.delegate = self;
    [geoCoder start];
}

// this delegate method is called if an error occurs in locating your current location
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error 
{
 NSLog(@"locationManager:%@ didFailWithError:%@", manager, error);
}

// this delegate is called when the reverseGeocoder finds a placemark
- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFindPlacemark:(MKPlacemark *)placemark
{
    MKPlacemark * myPlacemark = placemark;
    // with the placemark you can now retrieve the city name
    NSString *city = [myPlacemark.addressDictionary objectForKey:(NSString*) kABPersonAddressCityKey];
}

// this delegate is called when the reversegeocoder fails to find a placemark
- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFailWithError:(NSError *)error
{
    NSLog(@"reverseGeocoder:%@ didFailWithError:%@", geocoder, error);
}

回答by Gaurav

This is working fine for me :

这对我来说很好用：

CLGeocoder *geocoder = [[CLGeocoder alloc] init] ;
[geocoder reverseGeocodeLocation:self.locationManager.location
               completionHandler:^(NSArray *placemarks, NSError *error) {
                   NSLog(@"reverseGeocodeLocation:completionHandler: Completion Handler called!");

                   if (error){
                       NSLog(@"Geocode failed with error: %@", error);
                       return;

                   }


                   CLPlacemark *placemark = [placemarks objectAtIndex:0];

                   NSLog(@"placemark.ISOcountryCode %@",placemark.ISOcountryCode);
                   NSLog(@"placemark.country %@",placemark.country);
                   NSLog(@"placemark.postalCode %@",placemark.postalCode);
                   NSLog(@"placemark.administrativeArea %@",placemark.administrativeArea);
                   NSLog(@"placemark.locality %@",placemark.locality);
                   NSLog(@"placemark.subLocality %@",placemark.subLocality);
                   NSLog(@"placemark.subThoroughfare %@",placemark.subThoroughfare);

               }];

回答by Jonathan Field

If anyone is trying to move onto CLGeocoder from MKReverseGeocoder then I have written a blog post that might be of help http://jonathanfield.me/jons-blog/clgeocoder-example.html

如果有人试图从 MKReverseGeocoder 转向 CLGeocoder，那么我写了一篇可能有帮助的博客文章http://jonathanfield.me/jons-blog/clgeocoder-example.html

Basically an example would be, after you have created locationManager and CLGeocoder objects just add this code to your viewDidLoad() and then make some labels or text areas to show the data.

基本上一个例子是，在您创建 locationManager 和 CLGeocoder 对象之后，只需将此代码添加到您的 viewDidLoad() 中，然后制作一些标签或文本区域来显示数据。

  [super viewDidLoad];
    locationManager.delegate = self;
    [locationManager startUpdatingLocation];

    locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
    [self.CLGeocoder reverseGeocodeLocation: locationManager.location completionHandler: 
     ^(NSArray *placemarks, NSError *error) {


         CLPlacemark *placemark = [placemarks objectAtIndex:0];


             isoCountryCode.text = placemark.ISOcountryCode;
             country.text = placemark.country;
             postalCode.text= placemark.postalCode;
             adminArea.text=placemark.administrativeArea;
             subAdminArea.text=placemark.subAdministrativeArea;
             locality.text=placemark.locality;
             subLocality.text=placemark.subLocality;
             thoroughfare.text=placemark.thoroughfare;
             subThoroughfare.text=placemark.subThoroughfare;
             //region.text=placemark.region;



     }];

回答by Paula Hasstenteufel

If anyone needs it in Swift 3, this is how I did it:

如果有人在Swift 3 中需要它，我就是这样做的：

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

    let location = locations.first!
    let coordinateRegion = MKCoordinateRegionMakeWithDistance(location.coordinate, 500, 500)

    self.location = location
    self.locationManager?.stopUpdatingLocation()

    // Drop a pin at user's Current Location
    let myAnnotation: MKPointAnnotation = CustomPointAnnotation()
    myAnnotation.coordinate = CLLocationCoordinate2DMake(location.coordinate.latitude, location.coordinate.longitude)
    myAnnotation.title = "Localiza??o"
    self.mapViewMK.addAnnotation(myAnnotation)

    self.mapViewMK.setRegion(coordinateRegion, animated: true)
    self.locationManager?.stopUpdatingLocation()
    self.locationManager = nil

    // Get user's current location name
    let geocoder = CLGeocoder()
    geocoder.reverseGeocodeLocation(self.location!) { (placemarksArray, error) in

        if (placemarksArray?.count)! > 0 {

            let placemark = placemarksArray?.first
            let number = placemark!.subThoroughfare
            let bairro = placemark!.subLocality
            let street = placemark!.thoroughfare

            self.addressLabel.text = "\(street!), \(number!) - \(bairro!)"
        }
    }
}

回答by Michael Wang

After you setup CLLocationManager you would get location update as a latitude/longitude pair. Then you could use CLGeocoder to convert the coordinate to a user friendly place name.

设置 CLLocationManager 后，您将获得纬度/经度对的位置更新。然后您可以使用 CLGeocoder 将坐标转换为用户友好的地名。

Here is the sample code in Swift 4.

这是Swift 4 中的示例代码。

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    if let lastLocation = locations.last {
        let geocoder = CLGeocoder()

        geocoder.reverseGeocodeLocation(lastLocation) { [weak self] (placemarks, error) in
            if error == nil {
                if let firstLocation = placemarks?[0],
                    let cityName = firstLocation.locality { // get the city name
                    self?.locationManager.stopUpdatingLocation()
                }
            }
        }
    }
}

回答by Marcin Zbijowski

You have to get user's current location and then use MKReverseGeocoder to recognize the city.

您必须获取用户的当前位置，然后使用 MKReverseGeocoder 识别城市。

There's great example in iPhone App Programming Guide, chapter 8. Once you've got location initialize geocoder, set the delegate and read country from the placemark. Read the documentation for MKReverseGeocodeDelegate and create methods:

iPhone App Programming Guide，第8章中有一个很好的例子。一旦你有了位置初始化地理编码器，设置代表并从地标读取国家。阅读 MKReverseGeocodeDelegate 的文档并创建方法：

• reverseGeocoder:didFindPlacemark:

• reverseGeocoder:didFailWithError:

  MKReverseGeocoder *geocoder = [[MKReverseGeocoder alloc] initWithCoordinate:newLocation.coordinate];
  geocoder.delegate = self;
  [geocoder start];
  

• reverseGeocoder:didFindPlacemark:

• reverseGeocoder:didFailWithError:

  MKReverseGeocoder *geocoder = [[MKReverseGeocoder alloc] initWithCoordinate:newLocation.coordinate];
  geocoder.delegate = self;
  [geocoder start];
  

回答by Anand Kr. Avasthi

You can use this code for getting Current City:--

您可以使用此代码获取当前城市：--

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

extension YourController: CLLocationManagerDelegate { func locationManager(manager: CLLocationManager, didUpdateLocations location: [CLLocation]) {

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

        if (error != nil)
        {
            manager.stopUpdatingLocation()
            return
        }
        else
        {
            if placemarks!.count > 0
            {
                let placeMarksArrray: NSArray = placemarks!
                let pm = placeMarksArrray[0] as! CLPlacemark
                self.displayLocationInfo(pm)
                manager.stopUpdatingLocation()
            } else
            {
                print("Problem with the data received from geocoder")
            }
        }
    })
}

func displayLocationInfo(placemark: CLPlacemark!) {
    if (placemark != nil) {
        //stop updating location to save battery life
        locationLocation.stopUpdatingLocation()
        var tempString : String = ""
        if(placemark.locality != nil){
            tempString = tempString +  placemark.locality! + " "
            print(placemark.locality)
        }
        if(placemark.postalCode != nil){
            tempString = tempString +  placemark.postalCode! + " "
            print(placemark.postalCode)
        }
        if(placemark.administrativeArea != nil){
            tempString = tempString +  placemark.administrativeArea! + " "
            print(placemark.administrativeArea)
        }
        if(placemark.country != nil){
            tempString = tempString +  placemark.country! + " "



        }
        let dictForaddress = placemark.addressDictionary as! NSDictionary


        if let city = dictForaddress["City"] {
            print(city)



        }
        strLocation = tempString
    }
}

回答by Robert William Clancy

// place the function code below in desire location in program.

// [self getCurrentLocation];



-(void)getCurrentLocation
{
    CLGeocoder *geocoder = [[CLGeocoder alloc] init] ;
    [geocoder reverseGeocodeLocation:self->locationManager.location
                   completionHandler:^(NSArray *placemarks, NSError *error) {
                       NSLog(@"reverseGeocodeLocation:completionHandler: Completion Handler called!");

                       if (error){
                           NSLog(@"Geocode failed with error: %@", error);
                           return;

                       }


                       CLPlacemark *placemark = [placemarks objectAtIndex:0];

                       NSLog(@"placemark.ISOcountryCode %@",placemark.ISOcountryCode);
                       NSLog(@"placemark.country %@",placemark.country);
                        NSLog(@"placemark.locality %@",placemark.locality );
                       NSLog(@"placemark.postalCode %@",placemark.postalCode);
                       NSLog(@"placemark.administrativeArea %@",placemark.administrativeArea);
                       NSLog(@"placemark.locality %@",placemark.locality);
                       NSLog(@"placemark.subLocality %@",placemark.subLocality);
                       NSLog(@"placemark.subThoroughfare %@",placemark.subThoroughfare);

                   }];
}

回答by Timur Bernikovich

Here is my small Swift class which helps me with getting reverse geocoded information about current location. Don't forget about NSLocationWhenInUseUsageDescriptionfield in Info.plist.

这是我的小型 Swift 类，它帮助我获取有关当前位置的反向地理编码信息。不要忘记NSLocationWhenInUseUsageDescription字段 in Info.plist。

class CurrentPlacemarkUpdater: NSObject, CLLocationManagerDelegate {

    private let locationManager = CLLocationManager()
    private let geocoder = CLGeocoder()

    private(set) var latestPlacemark: CLPlacemark?
    var onLatestPlacemarkUpdate: (() -> ())?
    var shouldStopOnUpdate: Bool = true

    func start() {
        locationManager.requestWhenInUseAuthorization()
        locationManager.desiredAccuracy = kCLLocationAccuracyKilometer
        locationManager.delegate = self
        locationManager.startUpdatingLocation()
    }

    func stop() {
        locationManager.stopUpdatingLocation()
    }

    fileprivate func updatePlacemark(for location: CLLocation) {
        geocoder.reverseGeocodeLocation(location) { [weak self] placemarks, error in
            if let placemark = placemarks?.first {
                self?.latestPlacemark = placemark
                self?.onLatestPlacemarkUpdate?()
                if self?.shouldStopOnUpdate ?? false {
                    self?.stop()
                }
            }
        }
    }

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        if let location = locations.last {
            updatePlacemark(for: location)
        }
    }

    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        print("CurrentPlacemarkUpdater: \(error)")
    }

}