Select Current Place and Show Details on a Map
This tutorial demonstrates building an iOS app that retrieves the device's current location, identifies likely locations, prompts the user to select the best match, and displays a map marker for the chosen location.
It's suitable for those with a beginning or intermediate knowledge of Swift or Objective-C and a general knowledge of Xcode. For an advanced guide to creating maps, read the developers' guide .
You'll create the following map using this tutorial. The map marker is positioned in San Francisco, California, but will move to wherever the device or simulator is located.
This tutorial uses the Places SDK for iOS , the Maps SDK for iOS , and the Apple Core Location framework .
Get the code
Clone or download Google Maps iOS samples repository from GitHub.Alternatively, click the following button to download the source code:
MapViewController
Swift
import UIKit import GoogleMaps import GooglePlaces class MapViewController : UIViewController { var locationManager : CLLocationManager ! var currentLocation : CLLocation ? var mapView : GMSMapView ! var placesClient : GMSPlacesClient ! var preciseLocationZoomLevel : Float = 15.0 var approximateLocationZoomLevel : Float = 10.0 // An array to hold the list of likely places. var likelyPlaces : [ GMSPlace ] = [] // The currently selected place. var selectedPlace : GMSPlace ? // Update the map once the user has made their selection. @IBAction func unwindToMain ( segue : UIStoryboardSegue ) { // Clear the map. mapView . clear () // Add a marker to the map. if let place = selectedPlace { let marker = GMSMarker ( position : place . coordinate ) marker . title = selectedPlace ?. name marker . snippet = selectedPlace ?. formattedAddress marker . map = mapView } listLikelyPlaces () } override func viewDidLoad () { super . viewDidLoad () // Initialize the location manager. locationManager = CLLocationManager () locationManager . desiredAccuracy = kCLLocationAccuracyBest locationManager . requestWhenInUseAuthorization () locationManager . distanceFilter = 50 locationManager . startUpdatingLocation () locationManager . delegate = self placesClient = GMSPlacesClient . shared () // A default location to use when location permission is not granted. let defaultLocation = CLLocation ( latitude : - 33.869405 , longitude : 151.199 ) // Create a map. let zoomLevel = locationManager . accuracyAuthorization == . fullAccuracy ? preciseLocationZoomLevel : approximateLocationZoomLevel let camera = GMSCameraPosition . camera ( withLatitude : defaultLocation . coordinate . latitude , longitude : defaultLocation . coordinate . longitude , zoom : zoomLevel ) mapView = GMSMapView . map ( withFrame : view . bounds , camera : camera ) mapView . settings . myLocationButton = true mapView . autoresizingMask = [. flexibleWidth , . flexibleHeight ] mapView . isMyLocationEnabled = true // Add the map to the view, hide it until we've got a location update. view . addSubview ( mapView ) mapView . isHidden = true listLikelyPlaces () } // Populate the array with the list of likely places. func listLikelyPlaces () { // Clean up from previous sessions. likelyPlaces . removeAll () let placeFields : GMSPlaceField = [. name , . coordinate ] placesClient . findPlaceLikelihoodsFromCurrentLocation ( withPlaceFields : placeFields ) { ( placeLikelihoods , error ) in guard error == nil else { // TODO: Handle the error. print ( "Current Place error: \( error !. localizedDescription ) " ) return } guard let placeLikelihoods = placeLikelihoods else { print ( "No places found." ) return } // Get likely places and add to the list. for likelihood in placeLikelihoods { let place = likelihood . place self . likelyPlaces . append ( place ) } } } // Prepare the segue. override func prepare ( for segue : UIStoryboardSegue , sender : Any ?) { if segue . identifier == "segueToSelect" { if let nextViewController = segue . destination as ? PlacesViewController { nextViewController . likelyPlaces = likelyPlaces } } } } // Delegates to handle events for the location manager. extension MapViewController : CLLocationManagerDelegate { // Handle incoming location events. func locationManager ( _ manager : CLLocationManager , didUpdateLocations locations : [ CLLocation ]) { let location : CLLocation = locations . last ! print ( "Location: \( location ) " ) let zoomLevel = locationManager . accuracyAuthorization == . fullAccuracy ? preciseLocationZoomLevel : approximateLocationZoomLevel let camera = GMSCameraPosition . camera ( withLatitude : location . coordinate . latitude , longitude : location . coordinate . longitude , zoom : zoomLevel ) if mapView . isHidden { mapView . isHidden = false mapView . camera = camera } else { mapView . animate ( to : camera ) } listLikelyPlaces () } // Handle authorization for the location manager. func locationManager ( _ manager : CLLocationManager , didChangeAuthorization status : CLAuthorizationStatus ) { // Check accuracy authorization let accuracy = manager . accuracyAuthorization switch accuracy { case . fullAccuracy : print ( "Location accuracy is precise." ) case . reducedAccuracy : print ( "Location accuracy is not precise." ) @ unknown default : fatalError () } // Handle authorization status switch status { case . restricted : print ( "Location access was restricted." ) case . denied : print ( "User denied access to location." ) // Display the map using the default location. mapView . isHidden = false case . notDetermined : print ( "Location status not determined." ) case . authorizedAlways : fallthrough case . authorizedWhenInUse : print ( "Location status is OK." ) @ unknown default : fatalError () } } // Handle location manager errors. func locationManager ( _ manager : CLLocationManager , didFailWithError error : Error ) { locationManager . stopUpdatingLocation () print ( "Error: \( error ) " ) } }
Objective-C
#import "MapViewController.h" #import "PlacesViewController.h" @import CoreLocation ; @import GooglePlaces ; @import GoogleMaps ; @interface MapViewController () < CLLocationManagerDelegate > @end @implementation MapViewController { CLLocationManager * locationManager ; CLLocation * _Nullable currentLocation ; GMSMapView * mapView ; GMSPlacesClient * placesClient ; float preciseLocationZoomLevel ; float approximateLocationZoomLevel ; // An array to hold the list of likely places. NSMutableArray<GMSPlace * > * likelyPlaces ; // The currently selected place. GMSPlace * _Nullable selectedPlace ; } - ( void ) viewDidLoad { [ super viewDidLoad ]; preciseLocationZoomLevel = 15.0 ; approximateLocationZoomLevel = 15.0 ; // Initialize the location manager. locationManager = [[ CLLocationManager alloc ] init ]; locationManager . desiredAccuracy = kCLLocationAccuracyBest ; [ locationManager requestWhenInUseAuthorization ]; locationManager . distanceFilter = 50 ; [ locationManager startUpdatingLocation ]; locationManager . delegate = self ; placesClient = [ GMSPlacesClient sharedClient ]; // A default location to use when location permission is not granted. CLLocationCoordinate2D defaultLocation = CLLocationCoordinate2DMake ( -33.869405 , 151.199 ); // Create a map. float zoomLevel = locationManager . accuracyAuthorization == CLAccuracyAuthorizationFullAccuracy ? preciseLocationZoomLevel : approximateLocationZoomLevel ; GMSCameraPosition * camera = [ GMSCameraPosition cameraWithLatitude : defaultLocation . latitude longitude : defaultLocation . longitude zoom : zoomLevel ]; mapView = [ GMSMapView mapWithFrame : self . view . bounds camera : camera ]; mapView . settings . myLocationButton = YES ; mapView . autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight ; mapView . myLocationEnabled = YES ; // Add the map to the view, hide it until we've got a location update. [ self . view addSubview : mapView ]; mapView . hidden = YES ; [ self listLikelyPlaces ]; } // Populate the array with the list of likely places. - ( void ) listLikelyPlaces { // Clean up from previous sessions. likelyPlaces = [ NSMutableArray array ]; GMSPlaceField placeFields = GMSPlaceFieldName | GMSPlaceFieldCoordinate ; [ placesClient findPlaceLikelihoodsFromCurrentLocationWithPlaceFields : placeFields callback :^ ( NSArray<GMSPlaceLikelihood * > * _Nullable likelihoods , NSError * _Nullable error ) { if ( error != nil ) { // TODO: Handle the error. NSLog ( @"Current Place error: %@" , error . localizedDescription ); return ; } if ( likelihoods == nil ) { NSLog ( @"No places found." ); return ; } for ( GMSPlaceLikelihood * likelihood in likelihoods ) { GMSPlace * place = likelihood . place ; [ likelyPlaces addObject : place ]; } }]; } // Update the map once the user has made their selection. - ( void ) unwindToMain: ( UIStoryboardSegue * ) segue { // Clear the map. [ mapView clear ]; // Add a marker to the map. if ( selectedPlace != nil ) { GMSMarker * marker = [ GMSMarker markerWithPosition : selectedPlace . coordinate ]; marker . title = selectedPlace . name ; marker . snippet = selectedPlace . formattedAddress ; marker . map = mapView ; } [ self listLikelyPlaces ]; } // Prepare the segue. - ( void ) prepareForSegue: ( UIStoryboardSegue * ) segue sender: ( id ) sender { if ([ segue . identifier isEqualToString : @"segueToSelect" ]) { if ([ segue . destinationViewController isKindOfClass : [ PlacesViewController class ]]) { PlacesViewController * placesViewController = ( PlacesViewController * ) segue . destinationViewController ; placesViewController . likelyPlaces = likelyPlaces ; } } } // Delegates to handle events for the location manager. #pragma mark - CLLocationManagerDelegate // Handle incoming location events. - ( void ) locationManager: ( CLLocationManager * ) manager didUpdateLocations: ( NSArray<CLLocation * > * ) locations { CLLocation * location = locations . lastObject ; NSLog ( @"Location: %@" , location ); float zoomLevel = locationManager . accuracyAuthorization == CLAccuracyAuthorizationFullAccuracy ? preciseLocationZoomLevel : approximateLocationZoomLevel ; GMSCameraPosition * camera = [ GMSCameraPosition cameraWithLatitude : location . coordinate . latitude longitude : location . coordinate . longitude zoom : zoomLevel ]; if ( mapView . isHidden ) { mapView . hidden = NO ; mapView . camera = camera ; } else { [ mapView animateToCameraPosition : camera ]; } [ self listLikelyPlaces ]; } // Handle authorization for the location manager. - ( void ) locationManager: ( CLLocationManager * ) manager didChangeAuthorizationStatus: ( CLAuthorizationStatus ) status { // Check accuracy authorization CLAccuracyAuthorization accuracy = manager . accuracyAuthorization ; switch ( accuracy ) { case CLAccuracyAuthorizationFullAccuracy : NSLog ( @"Location accuracy is precise." ); break ; case CLAccuracyAuthorizationReducedAccuracy : NSLog ( @"Location accuracy is not precise." ); break ; } // Handle authorization status switch ( status ) { case kCLAuthorizationStatusRestricted : NSLog ( @"Location access was restricted." ); break ; case kCLAuthorizationStatusDenied : NSLog ( @"User denied access to location." ); // Display the map using the default location. mapView . hidden = NO ; case kCLAuthorizationStatusNotDetermined : NSLog ( @"Location status not determined." ); case kCLAuthorizationStatusAuthorizedAlways : case kCLAuthorizationStatusAuthorizedWhenInUse : NSLog ( @"Location status is OK." ); } } // Handle location manager errors. - ( void ) locationManager: ( CLLocationManager * ) manager didFailWithError: ( NSError * ) error { [ manager stopUpdatingLocation ]; NSLog ( @"Error: %@" , error . localizedDescription ); } @end
PlacesViewController
Swift
import UIKit import GooglePlaces class PlacesViewController : UIViewController { // ... // Pass the selected place to the new view controller. override func prepare ( for segue : UIStoryboardSegue , sender : Any ?) { if segue . identifier == "unwindToMain" { if let nextViewController = segue . destination as ? MapViewController { nextViewController . selectedPlace = selectedPlace } } } } // Respond when a user selects a place. extension PlacesViewController : UITableViewDelegate { func tableView ( _ tableView : UITableView , didSelectRowAt indexPath : IndexPath ) { selectedPlace = likelyPlaces [ indexPath . row ] performSegue ( withIdentifier : "unwindToMain" , sender : self ) } // Adjust cell height to only show the first five items in the table // (scrolling is disabled in IB). func tableView ( _ tableView : UITableView , heightForRowAt indexPath : IndexPath ) - > CGFloat { return self . tableView . frame . size . height / 5 } // Make table rows display at proper height if there are less than 5 items. func tableView ( _ tableView : UITableView , heightForFooterInSection section : Int ) - > CGFloat { if ( section == tableView . numberOfSections - 1 ) { return 1 } return 0 } } // Populate the table with the list of most likely places. extension PlacesViewController : UITableViewDataSource { func tableView ( _ tableView : UITableView , numberOfRowsInSection section : Int ) - > Int { return likelyPlaces . count } func tableView ( _ tableView : UITableView , cellForRowAt indexPath : IndexPath ) - > UITableViewCell { let cell = tableView . dequeueReusableCell ( withIdentifier : cellReuseIdentifier , for : indexPath ) let collectionItem = likelyPlaces [ indexPath . row ] cell . textLabel ?. text = collectionItem . name return cell } }
Objective-C
#import "PlacesViewController.h" @interface PlacesViewController () < UITableViewDataSource , UITableViewDelegate > // ... - ( void ) prepareForSegue : ( UIStoryboardSegue * ) segue sender : ( id ) sender { } #pragma mark - UITableViewDelegate // Respond when a user selects a place. - ( void ) tableView : ( UITableView * ) tableView didSelectRowAtIndexPath : ( NSIndexPath * ) indexPath { self . selectedPlace = [ self . likelyPlaces objectAtIndex : indexPath . row ]; [ self performSegueWithIdentifier : @"unwindToMain" sender : self ]; } // Adjust cell height to only show the first five items in the table // (scrolling is disabled in IB). - ( CGFloat ) tableView : ( UITableView * ) tableView heightForRowAtIndexPath : ( NSIndexPath * ) indexPath { return self . tableView . frame . size . height / 5 ; } // Make table rows display at proper height if there are less than 5 items. - ( CGFloat ) tableView : ( UITableView * ) tableView heightForFooterInSection : ( NSInteger ) section { if ( section == tableView . numberOfSections - 1 ) { return 1 ; } return 0 ; } #pragma mark - UITableViewDataSource - ( NSInteger ) tableView : ( UITableView * ) tableView numberOfRowsInSection : ( NSInteger ) section { return self . likelyPlaces . count ; } - ( UITableViewCell * ) tableView : ( UITableView * ) tableView cellForRowAtIndexPath : ( NSIndexPath * ) indexPath { return [ tableView dequeueReusableCellWithIdentifier : cellReuseIdentifier forIndexPath : indexPath ]; } @end
Get started
Swift Package Manager
The Maps SDK for iOS can be installed using Swift Package Manager .
- Remove any existing Maps SDK for iOS dependencies.
- Open a terminal window and navigate to the
tutorials/current-place-on-mapdirectory. - Close your Xcode workspace and run the following commands:
sudo gem install cocoapods - deintegrate cocoapods - clean pod deintegrate pod cache clean -- all rm Podfile rm current - place - on - map . xcworkspace
- Open your Xcode project and delete the podfile.
- Add the Places and Maps SDKs:
- Go to File > Add Package Dependencies .
- Enter https://github.com/googlemaps/ios-places-sdk as the URL, press Enter to pull in the package, and click Add Package .
- Enter https://github.com/googlemaps/ios-maps-sdk as the URL, press Enter to pull in the package, and click Add Package .
- You may need to reset your package cache using File > Packages > Reset Package Cache .
Use CocoaPods
- Download and install Xcode version 16.0or later.
- If you don't already have CocoaPods
,
install it on macOS by running the following command from the terminal:
sudo gem install cocoapods
- Navigate to the
tutorials/current-place-on-mapdirectory. - Run the
pod installcommand. This will install the Maps and Places SDKs specified in thePodfile, along with any dependencies. - Run
pod outdatedto compare the installed pod version with any new updates. If a new version is detected, runpod updateto update thePodfileand install the latest SDK. For more details, see the CocoaPods Guide . - Open (double-click) the project's current-place-on-map.xcworkspacefile to open it in Xcode. You must use the
.xcworkspacefile to open the project.
Get an API key and enable the necessary APIs
To complete this tutorial, you need a Google API key that's authorized to use the Maps SDK for iOSand the Places API.
- Follow the instructions on Get Started with Google Maps Platform to set up a billing account and a project enabled with both of these products.
- Follow the instructions on Get an API Key to create an API key for the development project you set up previously .
Add the API key to your application
Add your API key to your AppDelegate.swift
as follows:
- Note that following import statement has been added to the file:
import GooglePlaces import GoogleMaps
- Edit the following line in your
application(_:didFinishLaunchingWithOptions:)method, replacing YOUR_API_KEY with your API key:GMSPlacesClient.provideAPIKey(" YOUR_API_KEY ") GMSServices.provideAPIKey(" YOUR_API_KEY ")
Build and run your app
- Connect an iOS device to your computer, or select a simulator from the Xcode scheme menu.
- If you're using a device, make sure that location services are enabled. If you're using a simulator, select a location from the Featuresmenu.
- In Xcode, click the Product/Runmenu option (or the play button icon).
- Xcode builds the app, and then runs the app on the device or on the simulator.
- You should see a map with a number of markers centered around your current location.
Troubleshooting:
- If you don't see a map, check that you've obtained an API key and added it to the app, as described above . Check Xcode's debugging console for error messages about the API key.
- If you have restricted the API key by the iOS bundle identifier, edit the
key to add the bundle identifier for the app:
com.google.examples.current-place-on-map. - The map won't display properly if the permissions request for
location services is declined.
- If you're using a device, go to Settings/General/Privacy/Location Services, and re-enable location services.
- If you're using a simulator, go to Simulator/Reset Content and Settings...
- Make sure that you have a good Wi-Fi or GPS connection.
- If the app launches but no map is displayed, make sure that you have updated the Info.plist for your project with the appropriate location permissions. For more information about permissions handling, see the guide to requesting location permission in your app below.
- Use the Xcode debugging tools to view logs and debug the app.
Understand the code
This part of the tutorial explains the most significant parts of the current-place-on-mapapp, to help you understand how to build a similar app.
The current-place-on-mapapp features two view controllers:
One to display a map showing the user's selected place, and one
to present the user with a list of likely places to choose from. Note that
each view controller has the same variables for tracking the list of
likely places ( likelyPlaces
), and for indicating the user's
selection ( selectedPlace
). Navigation between views is
accomplished by using segues
.
Requesting location permission
Your app must prompt the user for consent to use location services. To do
this, include the NSLocationAlwaysUsageDescription
key in the Info.plist
file for the app, and set the value of each key to a
string that describes how the app intends to use location data.
Set up the location manager
Use CLLocationManager to find the device's current location and to request regular updates when the device moves to a new location. This tutorial provides the code you need to get the device's location. For more details, see the guide to Getting the User's Location in the Apple Developer Documentation.
- Declare the location manager, current location, map view, places client, and default zoom level at the class level.
- Initialize the location manager and
GMSPlacesClientinviewDidLoad(). - Declare variables to hold the list of likely places, and the user's selected place.
- Add delegates to handle events for the location manager, using an extension clause.
Swift
var locationManager : CLLocationManager ! var currentLocation : CLLocation ? var mapView : GMSMapView ! var placesClient : GMSPlacesClient ! var preciseLocationZoomLevel : Float = 15.0 var approximateLocationZoomLevel : Float = 10.0
Objective-C
CLLocationManager * locationManager ; CLLocation * _Nullable currentLocation ; GMSMapView * mapView ; GMSPlacesClient * placesClient ; float preciseLocationZoomLevel ; float approximateLocationZoomLevel ;
Swift
// Initialize the location manager. locationManager = CLLocationManager () locationManager . desiredAccuracy = kCLLocationAccuracyBest locationManager . requestWhenInUseAuthorization () locationManager . distanceFilter = 50 locationManager . startUpdatingLocation () locationManager . delegate = self placesClient = GMSPlacesClient . shared ()
Objective-C
// Initialize the location manager. locationManager = [[ CLLocationManager alloc ] init ]; locationManager . desiredAccuracy = kCLLocationAccuracyBest ; [ locationManager requestWhenInUseAuthorization ]; locationManager . distanceFilter = 50 ; [ locationManager startUpdatingLocation ]; locationManager . delegate = self ; placesClient = [ GMSPlacesClient sharedClient ];
Swift
// An array to hold the list of likely places. var likelyPlaces : [ GMSPlace ] = [] // The currently selected place. var selectedPlace : GMSPlace ?
Objective-C
// An array to hold the list of likely places. NSMutableArray<GMSPlace * > * likelyPlaces ; // The currently selected place. GMSPlace * _Nullable selectedPlace ;
Swift
// Delegates to handle events for the location manager. extension MapViewController : CLLocationManagerDelegate { // Handle incoming location events. func locationManager ( _ manager : CLLocationManager , didUpdateLocations locations : [ CLLocation ]) { let location : CLLocation = locations . last ! print ( "Location: \( location ) " ) let zoomLevel = locationManager . accuracyAuthorization == . fullAccuracy ? preciseLocationZoomLevel : approximateLocationZoomLevel let camera = GMSCameraPosition . camera ( withLatitude : location . coordinate . latitude , longitude : location . coordinate . longitude , zoom : zoomLevel ) if mapView . isHidden { mapView . isHidden = false mapView . camera = camera } else { mapView . animate ( to : camera ) } listLikelyPlaces () } // Handle authorization for the location manager. func locationManager ( _ manager : CLLocationManager , didChangeAuthorization status : CLAuthorizationStatus ) { // Check accuracy authorization let accuracy = manager . accuracyAuthorization switch accuracy { case . fullAccuracy : print ( "Location accuracy is precise." ) case . reducedAccuracy : print ( "Location accuracy is not precise." ) @ unknown default : fatalError () } // Handle authorization status switch status { case . restricted : print ( "Location access was restricted." ) case . denied : print ( "User denied access to location." ) // Display the map using the default location. mapView . isHidden = false case . notDetermined : print ( "Location status not determined." ) case . authorizedAlways : fallthrough case . authorizedWhenInUse : print ( "Location status is OK." ) @ unknown default : fatalError () } } // Handle location manager errors. func locationManager ( _ manager : CLLocationManager , didFailWithError error : Error ) { locationManager . stopUpdatingLocation () print ( "Error: \( error ) " ) } }
Objective-C
// Delegates to handle events for the location manager. #pragma mark - CLLocationManagerDelegate // Handle incoming location events. - ( void ) locationManager: ( CLLocationManager * ) manager didUpdateLocations: ( NSArray<CLLocation * > * ) locations { CLLocation * location = locations . lastObject ; NSLog ( @"Location: %@" , location ); float zoomLevel = locationManager . accuracyAuthorization == CLAccuracyAuthorizationFullAccuracy ? preciseLocationZoomLevel : approximateLocationZoomLevel ; GMSCameraPosition * camera = [ GMSCameraPosition cameraWithLatitude : location . coordinate . latitude longitude : location . coordinate . longitude zoom : zoomLevel ]; if ( mapView . isHidden ) { mapView . hidden = NO ; mapView . camera = camera ; } else { [ mapView animateToCameraPosition : camera ]; } [ self listLikelyPlaces ]; } // Handle authorization for the location manager. - ( void ) locationManager: ( CLLocationManager * ) manager didChangeAuthorizationStatus: ( CLAuthorizationStatus ) status { // Check accuracy authorization CLAccuracyAuthorization accuracy = manager . accuracyAuthorization ; switch ( accuracy ) { case CLAccuracyAuthorizationFullAccuracy : NSLog ( @"Location accuracy is precise." ); break ; case CLAccuracyAuthorizationReducedAccuracy : NSLog ( @"Location accuracy is not precise." ); break ; } // Handle authorization status switch ( status ) { case kCLAuthorizationStatusRestricted : NSLog ( @"Location access was restricted." ); break ; case kCLAuthorizationStatusDenied : NSLog ( @"User denied access to location." ); // Display the map using the default location. mapView . hidden = NO ; case kCLAuthorizationStatusNotDetermined : NSLog ( @"Location status not determined." ); case kCLAuthorizationStatusAuthorizedAlways : case kCLAuthorizationStatusAuthorizedWhenInUse : NSLog ( @"Location status is OK." ); } } // Handle location manager errors. - ( void ) locationManager: ( CLLocationManager * ) manager didFailWithError: ( NSError * ) error { [ manager stopUpdatingLocation ]; NSLog ( @"Error: %@" , error . localizedDescription ); }
Adding a map
Create a map and add it to the view in viewDidLoad()
in the
main view controller. The map stays hidden until a location update is received
(location updates are handled in the CLLocationManagerDelegate
extension).
Swift
// A default location to use when location permission is not granted. let defaultLocation = CLLocation ( latitude : - 33.869405 , longitude : 151.199 ) // Create a map. let zoomLevel = locationManager . accuracyAuthorization == . fullAccuracy ? preciseLocationZoomLevel : approximateLocationZoomLevel let camera = GMSCameraPosition . camera ( withLatitude : defaultLocation . coordinate . latitude , longitude : defaultLocation . coordinate . longitude , zoom : zoomLevel ) mapView = GMSMapView . map ( withFrame : view . bounds , camera : camera ) mapView . settings . myLocationButton = true mapView . autoresizingMask = [. flexibleWidth , . flexibleHeight ] mapView . isMyLocationEnabled = true // Add the map to the view, hide it until we've got a location update. view . addSubview ( mapView ) mapView . isHidden = true
Objective-C
// A default location to use when location permission is not granted. CLLocationCoordinate2D defaultLocation = CLLocationCoordinate2DMake ( -33.869405 , 151.199 ); // Create a map. float zoomLevel = locationManager . accuracyAuthorization == CLAccuracyAuthorizationFullAccuracy ? preciseLocationZoomLevel : approximateLocationZoomLevel ; GMSCameraPosition * camera = [ GMSCameraPosition cameraWithLatitude : defaultLocation . latitude longitude : defaultLocation . longitude zoom : zoomLevel ]; mapView = [ GMSMapView mapWithFrame : self . view . bounds camera : camera ]; mapView . settings . myLocationButton = YES ; mapView . autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight ; mapView . myLocationEnabled = YES ; // Add the map to the view, hide it until we've got a location update. [ self . view addSubview : mapView ]; mapView . hidden = YES ;
Prompting the user to select their current place
Use the Places SDK for iOS to get the top five place
likelihoods based on the user's current location, and present the list in a UITableView
. When the user selects a place, add a marker to the
map.
- Get a list of likely places to populate a
UITableView, from which the user can select the place where they are located. - Open a new view to present likely places to the user. When the user
taps "Get Place", we segue to a new view, and show the user a list of possible
places to choose from. The
preparefunction updatesPlacesViewControllerwith the list of current likely places, and is automatically called when a segue is performed. - In
PlacesViewController, fill the table using the list of most likely places, using theUITableViewDataSourcedelegate extension. - Handle the user's selection using the
UITableViewDelegatedelegate extension.
Swift
// Populate the array with the list of likely places. func listLikelyPlaces () { // Clean up from previous sessions. likelyPlaces . removeAll () let placeFields : GMSPlaceField = [. name , . coordinate ] placesClient . findPlaceLikelihoodsFromCurrentLocation ( withPlaceFields : placeFields ) { ( placeLikelihoods , error ) in guard error == nil else { // TODO: Handle the error. print ( "Current Place error: \( error !. localizedDescription ) " ) return } guard let placeLikelihoods = placeLikelihoods else { print ( "No places found." ) return } // Get likely places and add to the list. for likelihood in placeLikelihoods { let place = likelihood . place self . likelyPlaces . append ( place ) } } }
Objective-C
// Populate the array with the list of likely places. - ( void ) listLikelyPlaces { // Clean up from previous sessions. likelyPlaces = [ NSMutableArray array ]; GMSPlaceField placeFields = GMSPlaceFieldName | GMSPlaceFieldCoordinate ; [ placesClient findPlaceLikelihoodsFromCurrentLocationWithPlaceFields : placeFields callback :^ ( NSArray<GMSPlaceLikelihood * > * _Nullable likelihoods , NSError * _Nullable error ) { if ( error != nil ) { // TODO: Handle the error. NSLog ( @"Current Place error: %@" , error . localizedDescription ); return ; } if ( likelihoods == nil ) { NSLog ( @"No places found." ); return ; } for ( GMSPlaceLikelihood * likelihood in likelihoods ) { GMSPlace * place = likelihood . place ; [ likelyPlaces addObject : place ]; } }]; }
Swift
// Prepare the segue. override func prepare ( for segue : UIStoryboardSegue , sender : Any ?) { if segue . identifier == "segueToSelect" { if let nextViewController = segue . destination as ? PlacesViewController { nextViewController . likelyPlaces = likelyPlaces } } }
Objective-C
// Prepare the segue. - ( void ) prepareForSegue: ( UIStoryboardSegue * ) segue sender: ( id ) sender { if ([ segue . identifier isEqualToString : @"segueToSelect" ]) { if ([ segue . destinationViewController isKindOfClass : [ PlacesViewController class ]]) { PlacesViewController * placesViewController = ( PlacesViewController * ) segue . destinationViewController ; placesViewController . likelyPlaces = likelyPlaces ; } } }
Swift
// Populate the table with the list of most likely places. extension PlacesViewController : UITableViewDataSource { func tableView ( _ tableView : UITableView , numberOfRowsInSection section : Int ) - > Int { return likelyPlaces . count } func tableView ( _ tableView : UITableView , cellForRowAt indexPath : IndexPath ) - > UITableViewCell { let cell = tableView . dequeueReusableCell ( withIdentifier : cellReuseIdentifier , for : indexPath ) let collectionItem = likelyPlaces [ indexPath . row ] cell . textLabel ?. text = collectionItem . name return cell } }
Objective-C
#pragma mark - UITableViewDataSource - ( NSInteger ) tableView: ( UITableView * ) tableView numberOfRowsInSection: ( NSInteger ) section { return self . likelyPlaces . count ; } - ( UITableViewCell * ) tableView: ( UITableView * ) tableView cellForRowAtIndexPath: ( NSIndexPath * ) indexPath { return [ tableView dequeueReusableCellWithIdentifier : cellReuseIdentifier forIndexPath : indexPath ]; } @end
Swift
class PlacesViewController : UIViewController { // ... // Pass the selected place to the new view controller. override func prepare ( for segue : UIStoryboardSegue , sender : Any ?) { if segue . identifier == "unwindToMain" { if let nextViewController = segue . destination as ? MapViewController { nextViewController . selectedPlace = selectedPlace } } } } // Respond when a user selects a place. extension PlacesViewController : UITableViewDelegate { func tableView ( _ tableView : UITableView , didSelectRowAt indexPath : IndexPath ) { selectedPlace = likelyPlaces [ indexPath . row ] performSegue ( withIdentifier : "unwindToMain" , sender : self ) } // Adjust cell height to only show the first five items in the table // (scrolling is disabled in IB). func tableView ( _ tableView : UITableView , heightForRowAt indexPath : IndexPath ) - > CGFloat { return self . tableView . frame . size . height / 5 } // Make table rows display at proper height if there are less than 5 items. func tableView ( _ tableView : UITableView , heightForFooterInSection section : Int ) - > CGFloat { if ( section == tableView . numberOfSections - 1 ) { return 1 } return 0 } }
Objective-C
@interface PlacesViewController () < UITableViewDataSource , UITableViewDelegate > // ... - ( void ) prepareForSegue : ( UIStoryboardSegue * ) segue sender : ( id ) sender { } #pragma mark - UITableViewDelegate // Respond when a user selects a place. - ( void ) tableView : ( UITableView * ) tableView didSelectRowAtIndexPath : ( NSIndexPath * ) indexPath { self . selectedPlace = [ self . likelyPlaces objectAtIndex : indexPath . row ]; [ self performSegueWithIdentifier : @"unwindToMain" sender : self ]; } // Adjust cell height to only show the first five items in the table // (scrolling is disabled in IB). - ( CGFloat ) tableView : ( UITableView * ) tableView heightForRowAtIndexPath : ( NSIndexPath * ) indexPath { return self . tableView . frame . size . height / 5 ; } // Make table rows display at proper height if there are less than 5 items. - ( CGFloat ) tableView : ( UITableView * ) tableView heightForFooterInSection : ( NSInteger ) section { if ( section == tableView . numberOfSections - 1 ) { return 1 ; } return 0 ; }
Add a marker to the map
When the user makes a selection, use an unwind segue to return to the
previous view, and add the marker to the map. The unwindToMain
IBAction is called automatically upon returning to the main view controller.
Swift
// Update the map once the user has made their selection. @IBAction func unwindToMain ( segue : UIStoryboardSegue ) { // Clear the map. mapView . clear () // Add a marker to the map. if let place = selectedPlace { let marker = GMSMarker ( position : place . coordinate ) marker . title = selectedPlace ?. name marker . snippet = selectedPlace ?. formattedAddress marker . map = mapView } listLikelyPlaces () }
Objective-C
// Update the map once the user has made their selection. - ( void ) unwindToMain: ( UIStoryboardSegue * ) segue { // Clear the map. [ mapView clear ]; // Add a marker to the map. if ( selectedPlace != nil ) { GMSMarker * marker = [ GMSMarker markerWithPosition : selectedPlace . coordinate ]; marker . title = selectedPlace . name ; marker . snippet = selectedPlace . formattedAddress ; marker . map = mapView ; } [ self listLikelyPlaces ]; }
Congratulations!You've built an iOS app that lets the user choose their current place, and shows the result on a Google map. In the course of doing this, you've learned how to use the Places SDK for iOS , the Maps SDK for iOS , and the Apple Core Location framework .
