问题
I'm attempting to write a simple method that's fed CLLocationDegrees and returns a CLPlacemark. Looking at Apple's documentation, it seems like a simple task.
Below is what I've dumped into a playground:
import CoreLocation
// this is necessary for async code in a playground
import PlaygroundSupport
// this is necessary for async code in a playground
PlaygroundPage.current.needsIndefiniteExecution = true
func geocode(latitude: CLLocationDegrees, longitude: CLLocationDegrees) -> CLPlacemark? {
let location = CLLocation(latitude: latitude, longitude: longitude)
let geocoder = CLGeocoder()
var placemark: CLPlacemark?
geocoder.reverseGeocodeLocation(location) { (placemarks, error) in
if error != nil {
print("something went horribly wrong")
}
if let placemarks = placemarks {
placemark = placemarks.first
}
}
return placemark
}
let myPlacemark = geocode(latitude: 37.3318, longitude: 122.0312)
As it stands, my method is returning nil. I'm not sure where my error lies, but I rest assured it's something starlingly stupid on my part. Thank you for reading.
回答1:
import UIKit
import CoreLocation
import PlaygroundSupport
PlaygroundPage.current.needsIndefiniteExecution = true
func geocode(latitude: Double, longitude: Double, completion: @escaping (_ placemark: [CLPlacemark]?, _ error: Error?) -> Void) {
CLGeocoder().reverseGeocodeLocation(CLLocation(latitude: latitude, longitude: longitude)) { placemark, error in
guard let placemark = placemark, error == nil else {
completion(nil, error)
return
}
completion(placemark, nil)
}
}
or simply:
func geocode(latitude: Double, longitude: Double, completion: @escaping (_ placemark: [CLPlacemark]?, _ error: Error?) -> Void) {
CLGeocoder().reverseGeocodeLocation(CLLocation(latitude: latitude, longitude: longitude), completionHandler: completion)
}
or extending CLLocation:
extension CLLocation {
func geocode(completion: @escaping (_ placemark: [CLPlacemark]?, _ error: Error?) -> Void) {
CLGeocoder().reverseGeocodeLocation(self, completionHandler: completion)
}
}
To format your place mark as a mailing address you can use Contacts framework CNPostalAddressFormatter:
import Contacts
extension Formatter {
static let mailingAddress: CNPostalAddressFormatter = {
let formatter = CNPostalAddressFormatter()
formatter.style = .mailingAddress
return formatter
}()
}
extension CLPlacemark {
var mailingAddress: String? {
return postalAddress?.mailingAddress
}
}
extension CNPostalAddress {
var mailingAddress: String {
return Formatter.mailingAddress.string(from: self)
}
}
placemark
Contains an array of CLPlacemark objects. For most geocoding requests, this array should contain only one entry. However, forward-geocoding requests may return multiple placemark objects in situations where the specified address could not be resolved to a single location. If the request was canceled or there was an error in obtaining the placemark information, this parameter is nil.
For more information about the CLPlacemark properties you can check this CLPlacemark
Usage:
let location = CLLocation(latitude: -22.963451, longitude: -43.198242)
location.geocode { placemark, error in
if let error = error as? CLError {
print("CLError:", error)
return
} else if let placemark = placemark?.first {
// you should always update your UI in the main thread
DispatchQueue.main.async {
// update UI here
print("name:", placemark.name ?? "unknown")
print("address1:", placemark.thoroughfare ?? "unknown")
print("address2:", placemark.subThoroughfare ?? "unknown")
print("neighborhood:", placemark.subLocality ?? "unknown")
print("city:", placemark.locality ?? "unknown")
print("state:", placemark.administrativeArea ?? "unknown")
print("subAdministrativeArea:", placemark.subAdministrativeArea ?? "unknown")
print("zip code:", placemark.postalCode ?? "unknown")
print("country:", placemark.country ?? "unknown", terminator: "\n\n")
print("isoCountryCode:", placemark.isoCountryCode ?? "unknown")
print("region identifier:", placemark.region?.identifier ?? "unknown")
print("timezone:", placemark.timeZone ?? "unknown", terminator:"\n\n")
// Mailind Address
print(placemark.mailingAddress ?? "unknown")
}
}
}
This will print
name: Morro da Saudade
address1: Rua Casuarina
address2: 597
neighborhood: Lagoa
city: Rio de Janeiro
state: RJ
subAdministrativeArea: unknown
zip code: 22011-040
country: Brazil
isoCountryCode: BR
region identifier: <-22.96345100,-43.19824200> radius 141.83
timezone: America/Sao_Paulo (current)
Rua Casuarina, 597
Lagoa
Rio de Janeiro RJ
22011-040
Brazil
回答2:
There are so many questions dealing with 'reverseGeocodeLocation' on Stack Overflow, I've seen so many of them. I'm using Swift 4.2 and I thought my 'reverseGeocodeLocation' requests might be timing out. Well, this is NOT the case, when starting to move with an iPhone the 'didUpdateLocations' cycles need to mature. It can take two or more cycles before 'reverseGeocodeLocation' returns placemarks.
I wrote a simple app that uses 'reverseGeocodeLocation' until 'placemarks' are returned after repeated 'didUpdateLocations' cycles. This is my own home grown 'SampleCode'. I learned a lot from using the app, it might help others understand how reverse geocode requests work in the real world.
Please give your comments on possible improvements. This code is freely given and freely taken.
import Foundation
import UIKit
import CoreLocation
class ViewController: UIViewController, CLLocationManagerDelegate {
@IBAction func RefreshLocationButton(_ sender: Any) {
self.requestingPlacemark = true
self.placemarkData = nil
//^Make another Placemark Request
self.requestCounter = 0
self.RequestCounterLabel.text = ""
self.LocationLabel.text = ""
self.PlacemarkLabel.text = ""}
@IBOutlet weak var LocationCounterLabel: UILabel!
@IBOutlet weak var RequestCounterLabel: UILabel!
@IBOutlet weak var LocationLabel: UILabel!
@IBOutlet weak var PlacemarkLabel: UILabel!
let locationManager = CLLocationManager()
var placemarkData: CLPlacemark!
var placemarkString: String!
var printPlacemarkData: Bool!
var didUpdateLocationsCounter: Int = 0
var requestCounter: Int = 0
var requestingPlacemark: Bool = true
override func viewDidLoad() {
super.viewDidLoad()
if CLLocationManager.locationServicesEnabled() {
locationManager.requestAlwaysAuthorization()
locationManager.delegate = self
//locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation
locationManager.startUpdatingLocation()
self.RequestCounterLabel.text = ""
self.LocationLabel.text = ""
self.PlacemarkLabel.text = ""}}
func printPlacemarks() {
if printPlacemarkData {
self.placemarkString = "Placemark Data:"
self.placemarkString = buildPlacemarkString(item: 1)
self.placemarkString = buildPlacemarkString(item: 2)
self.placemarkString = buildPlacemarkString(item: 3)
self.placemarkString = buildPlacemarkString(item: 4)
self.placemarkString = buildPlacemarkString(item: 5)
self.placemarkString = buildPlacemarkString(item: 6)
self.placemarkString = buildPlacemarkString(item: 7)
self.placemarkString = buildPlacemarkString(item: 8)
self.placemarkString = buildPlacemarkString(item: 9)
self.placemarkString = buildPlacemarkString(item: 10)
self.PlacemarkLabel.text = self.placemarkString
self.printPlacemarkData = false}}
func buildPlacemarkString(item: Int) -> String {
var elementText: String!
var newString: String!
switch item {
case 1: elementText = "name: " + self.placemarkData.name!
case 2: elementText = "subThoroughfare: " + self.placemarkData.subThoroughfare!
case 3: elementText = "thoroughfare: " + self.placemarkData.thoroughfare!
case 4: elementText = "postalCode: " + self.placemarkData.postalCode!
case 5: elementText = "subLocality: " + self.placemarkData.subLocality!
case 6: elementText = "locality: " + self.placemarkData.locality!
case 7: elementText = "subAdministrativeArea: " + self.placemarkData.subAdministrativeArea!
case 8: elementText = "administrativeArea: " + self.placemarkData.administrativeArea!
case 9: elementText = "country: " + self.placemarkData.country!
case 10: elementText = "isoCountryCode: " + self.placemarkData.isoCountryCode!
default: print("Error: incorrect item number!")}
newString = self.placemarkString + "\n" + elementText
return newString
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
//location prints one time and 'didUpdateLocations' is stopped:
self.didUpdateLocationsCounter = self.didUpdateLocationsCounter + 1
let labelString = String(describing: self.didUpdateLocationsCounter)
self.LocationCounterLabel.text = "Location Update Counter: " + labelString
if self.placemarkData == nil {
//location variable:
self.requestCounter = self.requestCounter + 1
let textString = String(describing: self.requestCounter)
self.RequestCounterLabel.text = "Request Counter: " + textString
if locations.count == 0 {
self.LocationLabel.text = "Locations: There was NONE"}
else {
if locations.count > 0 {
let coordinate2D: CLLocation = locations.first!
let location = CLLocation(latitude: coordinate2D.coordinate.latitude, longitude: coordinate2D.coordinate.longitude)
let printString = String(describing: location)
self.LocationLabel.text = "Location: " + printString
let geocoder: CLGeocoder = CLGeocoder()
geocoder.reverseGeocodeLocation(location, completionHandler: {(placemarks, error) -> Void in
if error != nil {
let errorString = String(describing: error?.localizedDescription)
print("reverse geodcode fail: \(errorString)")
self.LocationCounterLabel.text = ""
self.RequestCounterLabel.text = ""
self.LocationLabel.text = "Reverse Geodcode fail: \(errorString)"
self.PlacemarkLabel.text = ""
self.requestingPlacemark = false
return}
else {
let pm = placemarks! as [CLPlacemark]
//There is ALWAYS 'placemarks' Data
if pm.count > 0 {
self.placemarkData = placemarks![0]
self.printPlacemarkData = true
self.printPlacemarks()
self.requestingPlacemark = false}}})}
else {
if self.requestingPlacemark {
self.LocationLabel.text = "Problem: There is no 'location.first'"}}}}}}
And then the Storyboard UI:
Storyboard Image
View Controller Image
<?xml version="1.0" encoding="UTF-8"?>
<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="14460.31" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="BYZ-38-t0r">
<device id="retina4_7" orientation="portrait">
<adaptation id="fullscreen"/>
</device>
<dependencies>
<deployment identifier="iOS"/>
<plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="14460.20"/>
<capability name="Safe area layout guides" minToolsVersion="9.0"/>
<capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
</dependencies>
<scenes>
<!--View Controller-->
<scene sceneID="tne-QT-ifu">
<objects>
<viewController id="BYZ-38-t0r" customClass="ViewController" customModule="MyThoroughfare" customModuleProvider="target" sceneMemberID="viewController">
<view key="view" contentMode="scaleToFill" id="8bC-Xf-vdC">
<rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
<autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
<subviews>
<label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Location Counter" lineBreakMode="tailTruncation" numberOfLines="2" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="ZIg-u9-TMR">
<rect key="frame" x="16" y="20" width="343" height="20.5"/>
<color key="backgroundColor" red="0.80000001190000003" green="0.80000001190000003" blue="0.80000001190000003" alpha="1" colorSpace="calibratedRGB"/>
<fontDescription key="fontDescription" type="system" pointSize="17"/>
<nil key="textColor"/>
<nil key="highlightedColor"/>
</label>
<label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Location Count Label" lineBreakMode="tailTruncation" numberOfLines="2" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="csF-KS-xGE">
<rect key="frame" x="16" y="48" width="343" height="20.5"/>
<color key="backgroundColor" red="0.80000001190000003" green="0.80000001190000003" blue="0.80000001190000003" alpha="1" colorSpace="calibratedRGB"/>
<fontDescription key="fontDescription" type="system" pointSize="17"/>
<nil key="textColor"/>
<nil key="highlightedColor"/>
</label>
<label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Location String" lineBreakMode="tailTruncation" numberOfLines="8" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="qOc-gk-gSp">
<rect key="frame" x="16" y="76" width="343" height="20.5"/>
<color key="backgroundColor" red="0.80000001190000003" green="0.80000001190000003" blue="0.80000001190000003" alpha="1" colorSpace="calibratedRGB"/>
<fontDescription key="fontDescription" type="system" pointSize="17"/>
<nil key="textColor"/>
<nil key="highlightedColor"/>
</label>
<label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Placemark String" lineBreakMode="tailTruncation" numberOfLines="14" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="42A-nO-tNf">
<rect key="frame" x="16" y="104" width="343" height="20.5"/>
<color key="backgroundColor" red="0.80000001190000003" green="0.80000001190000003" blue="0.80000001190000003" alpha="1" colorSpace="calibratedRGB"/>
<fontDescription key="fontDescription" type="system" pointSize="17"/>
<nil key="textColor"/>
<nil key="highlightedColor"/>
</label>
<button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="HgN-oB-ds0">
<rect key="frame" x="121.5" y="578" width="132" height="30"/>
<state key="normal" title="Request Placemark"/>
<connections>
<action selector="RefreshLocationButton:" destination="BYZ-38-t0r" eventType="touchUpInside" id="izY-S5-wjg"/>
</connections>
</button>
</subviews>
<color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
<constraints>
<constraint firstItem="ZIg-u9-TMR" firstAttribute="leading" secondItem="6Tk-OE-BBY" secondAttribute="leading" constant="16" id="6HO-kN-l1z"/>
<constraint firstItem="qOc-gk-gSp" firstAttribute="top" secondItem="csF-KS-xGE" secondAttribute="bottom" constant="7.5" id="6ux-dx-gJr"/>
<constraint firstItem="6Tk-OE-BBY" firstAttribute="trailing" secondItem="42A-nO-tNf" secondAttribute="trailing" constant="16" id="8dG-gV-Cob"/>
<constraint firstItem="HgN-oB-ds0" firstAttribute="centerX" secondItem="8bC-Xf-vdC" secondAttribute="centerX" id="A38-Nt-i3D"/>
<constraint firstItem="6Tk-OE-BBY" firstAttribute="trailing" secondItem="ZIg-u9-TMR" secondAttribute="trailing" constant="16" id="Bb0-YC-oov"/>
<constraint firstItem="csF-KS-xGE" firstAttribute="leading" secondItem="6Tk-OE-BBY" secondAttribute="leading" constant="16" id="FJU-ha-HkL"/>
<constraint firstItem="42A-nO-tNf" firstAttribute="top" secondItem="qOc-gk-gSp" secondAttribute="bottom" constant="7.5" id="SpR-XB-MLG"/>
<constraint firstItem="6Tk-OE-BBY" firstAttribute="bottom" secondItem="HgN-oB-ds0" secondAttribute="bottom" constant="59" id="Vr6-QE-230"/>
<constraint firstItem="42A-nO-tNf" firstAttribute="leading" secondItem="6Tk-OE-BBY" secondAttribute="leading" constant="16" id="aHo-kJ-aCb"/>
<constraint firstItem="csF-KS-xGE" firstAttribute="top" secondItem="ZIg-u9-TMR" secondAttribute="bottom" constant="7.5" id="c63-Mq-ItW"/>
<constraint firstItem="6Tk-OE-BBY" firstAttribute="trailing" secondItem="csF-KS-xGE" secondAttribute="trailing" constant="16" id="dlV-Hc-8XJ"/>
<constraint firstItem="qOc-gk-gSp" firstAttribute="leading" secondItem="6Tk-OE-BBY" secondAttribute="leading" constant="16" id="m5y-Q8-jxI"/>
<constraint firstItem="ZIg-u9-TMR" firstAttribute="top" secondItem="6Tk-OE-BBY" secondAttribute="top" id="sdw-WQ-Bx9"/>
<constraint firstItem="6Tk-OE-BBY" firstAttribute="trailing" secondItem="qOc-gk-gSp" secondAttribute="trailing" constant="16" id="woB-ig-i5v"/>
</constraints>
<viewLayoutGuide key="safeArea" id="6Tk-OE-BBY"/>
</view>
<connections>
<outlet property="LocationCounterLabel" destination="ZIg-u9-TMR" id="K4g-WT-f82"/>
<outlet property="LocationLabel" destination="qOc-gk-gSp" id="Cdw-bw-EWt"/>
<outlet property="PlacemarkLabel" destination="42A-nO-tNf" id="dMh-bw-cRE"/>
<outlet property="RequestCounterLabel" destination="csF-KS-xGE" id="ai6-zn-Toi"/>
</connections>
</viewController>
<placeholder placeholderIdentifier="IBFirstResponder" id="dkx-z0-nzr" sceneMemberID="firstResponder"/>
</objects>
<point key="canvasLocation" x="53.600000000000001" y="66.11694152923539"/>
</scene>
</scenes>
</document>
来源：https://stackoverflow.com/questions/46869394/reverse-geocoding-in-swift-4