Selecionar o lugar atual e exibir detalhes em um mapa

Este tutorial demonstra a criação de um app iOS que recupera a localização atual do dispositivo, identifica locais prováveis, solicita que o usuário selecione a melhor correspondência e exibe um marcador de mapa para o local escolhido.

É adequado para quem tem conhecimento básico ou intermediário de Swift ou Objective-C e conhecimento geral do Xcode. Se quiser consultar um guia avançado sobre a criação de mapas, leia o Guia do desenvolvedor.

Neste tutorial, você criará o mapa a seguir. O marcador do mapa está posicionado em São Francisco, Califórnia, mas será movido para onde o dispositivo ou simulador estiver localizado.

Este tutorial usa o SDK do Places para iOS, o SDK do Maps para iOS e o framework da localização principal da Apple.

Acessar o código

Clone ou faça o download do repositório de exemplos do Google Maps para iOS do GitHub.

Como alternativa, clique no botão a seguir para fazer o download do código-fonte:

Informar o código

MapViewController Swift

/*
 * Copyright 2016 Google Inc. All rights reserved.
 *
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this
 * file except in compliance with the License. You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under
 * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
 * ANY KIND, either express or implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */

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)")
  }
}

      

PlacesViewController do Swift

/*
 * Copyright 2017 Google Inc. All rights reserved.
 *
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this
 * file except in compliance with the License. You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under
 * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
 * ANY KIND, either express or implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */

import UIKit
import GooglePlaces

class PlacesViewController: UIViewController {

  @IBOutlet weak var tableView: UITableView!

  // An array to hold the list of possible locations.
  var likelyPlaces: [GMSPlace] = []
  var selectedPlace: GMSPlace?

  // Cell reuse id (cells that scroll out of view can be reused).
  let cellReuseIdentifier = "cell"

  override func viewDidLoad() {
    super.viewDidLoad()

    // Register the table view cell class and its reuse id.
    tableView.register(UITableViewCell.self, forCellReuseIdentifier: cellReuseIdentifier)

    // This view controller provides delegate methods and row data for the table view.
    tableView.delegate = self
    tableView.dataSource = self

    tableView.reloadData()
  }

  // 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
  }
}

      

MapViewController Obj-C

//
//  MapsViewController.m
//  current-place-on-map
//
//  Created by Chris Arriola on 9/18/20.
//  Copyright © 2020 William French. All rights reserved.
//

#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 Obj-C

// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#import "PlacesViewController.h"

@interface PlacesViewController () <UITableViewDataSource, UITableViewDelegate>
@property (nonatomic, weak) UITableView *tableView;
@end

@implementation PlacesViewController {
  // Cell reuse id (cells that scroll out of view can be reused).
  NSString *cellReuseIdentifier;
}

- (void)viewDidLoad {
  [super viewDidLoad];
  cellReuseIdentifier = @"cell";
}

-(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

      

Primeiros passos

Gerenciador de pacotes do Swift

O SDK do Maps para iOS pode ser instalado usando o Swift Package Manager.

  1. Verifique se você removeu todas as dependências atuais do SDK do Maps para iOS.
  2. Abra uma janela de terminal e navegue até o diretório tutorials/current-place-on-map.
  3. Verifique se o espaço de trabalho do Xcode está fechado e execute os seguintes comandos:
    sudo gem install cocoapods-deintegrate cocoapods-clean
    pod deintegrate
    pod cache clean --all
    rm Podfile
    rm current-place-on-map.xcworkspace
  4. Abra seu projeto do Xcode e exclua o podfile.
  5. Adicione os SDKs do Places e do Maps:
    1. Acesse Arquivo > Adicionar dependências de pacotes.
    2. Digite https://github.com/googlemaps/ios-places-sdk como o URL, pressione Enter para extrair o pacote e clique em Adicionar pacote.
    3. Digite https://github.com/googlemaps/ios-maps-sdk como o URL, pressione Enter para extrair o pacote e clique em Adicionar pacote.
  6. Talvez seja necessário redefinir o cache de pacotes em Arquivo > Pacotes > Redefinir cache de pacote.

Usar o CocoaPods

  1. Faça o download e instale o Xcode versão 14.0 ou mais recente.
  2. Se você ainda não tem o CocoaPods, instale-o no macOS executando o seguinte comando no terminal:
    sudo gem install cocoapods
  3. Navegue até o diretório tutorials/current-place-on-map.
  4. Execute o comando pod install. Isso vai instalar os SDKs do Maps e do Places especificados em Podfile, com todas as dependências.
  5. Execute pod outdated para comparar a versão do pod instalada com novas atualizações. Se uma nova versão for detectada, execute pod update para atualizar o Podfile e instalar o SDK mais recente. Para mais detalhes, consulte o Guia do CocoaPods (em inglês).
  6. Abra (clique duas vezes) o arquivo current-place-on-map.xcworkspace do projeto para abri-lo no Xcode. Use o arquivo .xcworkspace para abrir o projeto.

Gerar uma chave de API e ativar as APIs necessárias

Para concluir este tutorial, você precisa de uma chave de API do Google que possa usar o SDK do Maps para iOS e a API Places.

  1. Siga as instruções em Começar a usar a Plataforma Google Maps para configurar uma conta de faturamento e um projeto ativado com esses dois produtos.
  2. Siga as instruções em Gerar uma chave de API para criar uma para o projeto de desenvolvimento configurado anteriormente.

Adicionar a chave de API a seu aplicativo

Inclua sua chave de API ao AppDelegate.swift da seguinte maneira:

  1. Observe que a seguinte instrução de importação foi adicionada ao arquivo:
    import GooglePlaces
    import GoogleMaps
  2. Edite a linha a seguir no método application(_:didFinishLaunchingWithOptions:), substituindo YOUR_API_KEY pela chave de API:
    GMSPlacesClient.provideAPIKey("YOUR_API_KEY")
    GMSServices.provideAPIKey("YOUR_API_KEY")

Criar e executar o app

  1. Conecte um dispositivo iOS ao computador ou selecione um simulador no menu pop-up de esquema do Xcode.
  2. Se estiver usando um dispositivo, certifique-se de que os serviços de localização estejam ativados. Se você estiver usando um simulador, selecione um local no menu Recursos.
  3. No Xcode, clique na opção de menu Product/Run ou no ícone do botão de reprodução.
    • O Xcode compila o app e o executa no dispositivo ou no simulador.
    • Vai aparecer um mapa com vários marcadores centralizados ao redor do seu local atual.

Solução de problemas:

  • Se o mapa não aparecer, confirme se você recebeu uma chave de API e a incluiu no app, como descrito acima. Verifique se há mensagens de erro sobre a chave de API no console de depuração do Xcode.
  • Se você restringiu a chave de API pelo identificador do pacote iOS, edite a chave para adicionar o identificador do pacote no app: com.google.examples.current-place-on-map.
  • O mapa não vai ser mostrado corretamente se a solicitação de permissão para os Serviços de localização for recusada.
    • Se você estiver usando um dispositivo, acesse Configurações/Geral/Privacidade/Serviços de localização e reative os Serviços de localização.
    • Se você estiver usando um simulador, acesse Simulador/Redefinir conteúdo e configurações...
    Na próxima vez que o app for executado, aceite a solicitação dos Serviços de localização.
  • Verifique se você tem uma boa conexão Wi-Fi ou GPS.
  • Se o app for iniciado, mas nenhum mapa for exibido, atualize o Info.plist do projeto com as permissões de localização apropriadas. Para saber mais sobre o gerenciamento de permissões, consulte o guia sobre como solicitar permissões de localização no seu app abaixo.
  • Use as ferramentas de depuração do Xcode para conferir os registros e depurar o app.

Entender o código

Nesta seção do tutorial, explicamos as partes mais importantes do app current-place-on-map para ajudar você a criar um app semelhante.

O app current-place-on-map tem dois controladores de visualização: um para mostrar um mapa com o lugar selecionado do usuário e outro para apresentar uma lista de possíveis lugares para escolher. Cada controlador de visualização tem as mesmas variáveis para rastrear a lista de lugares prováveis (likelyPlaces) e indicar a seleção do usuário (selectedPlace). A navegação entre visualizações é realizada usando segues.

Solicitando permissão de localização

Seu app precisa solicitar o consentimento do usuário para usar os Serviços de localização. Para fazer isso, inclua a chave NSLocationAlwaysUsageDescription no arquivo Info.plist do app e defina o valor de cada chave como uma string que descreve como o app pretende usar os dados de local.

Como configurar o gerenciador de locais

Use CLLocationManager para encontrar a localização atual do dispositivo e solicitar atualizações regulares quando ele se mover para um novo local. Neste tutorial, fornecemos o código necessário para saber a localização do dispositivo. Para mais detalhes, consulte o guia sobre Como saber a localização do usuário na documentação do desenvolvedor da Apple.

  1. Declare o gerenciador de localização, a localização atual, a visualização de mapa, o cliente do Places e o nível de zoom padrão no nível da classe.
  2. 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;
          
  3. Inicialize o gerenciador de locais e o GMSPlacesClient no viewDidLoad().
  4. 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];
          
  5. Declare variáveis para conter a lista de lugares prováveis e o lugar selecionado pelo usuário.
  6. 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;
          
  7. Adicione delegados para processar eventos do gerenciador de locais usando uma cláusula de extensão.
  8. 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);
    }
          

Adicionar um mapa

Crie um mapa e adicione-o à visualização em viewDidLoad() no controlador de visualização principal. O mapa permanece oculto até que uma atualização de local seja recebida (as atualizações de local são processadas na extensão CLLocationManagerDelegate).

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;
      

Solicitar que o usuário selecione o lugar atual

Use o SDK do Places para iOS se quiser ver as cinco principais probabilidades de lugares com base na localização atual do usuário e apresentar a lista em um UITableView. Quando o usuário selecionar um lugar, adicione um marcador ao mapa.

  1. Consiga uma lista de possíveis lugares para preencher um UITableView, em que o usuário pode selecionar o lugar em que está localizado no momento.
  2. 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];
        }
      }];
    }
          
  3. Abra uma nova visualização para mostrar lugares prováveis ao usuário. Quando o usuário toca em "Get Place", passamos para uma nova visualização e mostramos a ele uma lista de possíveis lugares para escolher. A função prepare atualiza PlacesViewController com a lista de locais prováveis atuais e é chamada automaticamente quando uma transição é realizada.
  4. 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;
        }
      }
    }
          
  5. Em PlacesViewController, preencha a tabela usando a lista de lugares mais prováveis, usando a extensão delegada UITableViewDataSource.
  6. 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
          
  7. Processe a seleção do usuário usando a extensão delegada UITableViewDelegate.
  8. 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;
    }
          

Adicionar um marcador ao mapa

Quando o usuário fizer uma seleção, use uma sequência de descanso para retornar à visualização anterior e adicionar o marcador ao mapa. A IBAction unwindToMain é chamada automaticamente ao retornar ao controlador de visualização principal.

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];
}
      

Parabéns! Você criou um app iOS que permite que o usuário escolha o lugar atual e mostra o resultado em um mapa do Google. Durante esse processo, você aprendeu a usar o SDK do Places para iOS, o SDK do Maps para iOS e o framework da localização principal da Apple.