要在两个坐标之间绘制路线,您需要向Google Maps Directions API发出请求并解析其响应。因此,您首先需要为您的请求获取一个API密钥。您可以通过创建一个项目并在该项目中启用Google Maps Directions API来获得一个
here。
假设您已经安装了Google Maps SDK,您需要向Directions API发出请求,然后解析其响应。一旦您解析了响应JSON,就可以创建一个GMSPath对象。我喜欢使用具有两个输入(start和end CLLocationCoordinate2D对象)的函数来完成这项工作,并在成功时返回GMSPath或在出现错误时返回错误。下面的代码是Swift 3的。
我的类及其函数如下:
import Foundation
import CoreLocation
import GoogleMaps
class SessionManager {
let GOOGLE_DIRECTIONS_API_KEY = "INSERT_YOUR_API_KEY_HERE"
func requestDirections(from start: CLLocationCoordinate2D, to end: CLLocationCoordinate2D, completionHandler: @escaping ((_ response: GMSPath?, _ error: Error?) -> Void)) {
guard let url = URL(string: "https://maps.googleapis.com/maps/api/directions/json?origin=\(start.latitude),\(start.longitude)&destination=\(end.latitude),\(end.longitude)&key=\(GOOGLE_DIRECTIONS_API_KEY)") else {
let error = NSError(domain: "LocalDomain", code: 0, userInfo: [NSLocalizedDescriptionKey: "Failed to create object URL"])
print("Error: \(error)")
completionHandler(nil, error)
return
}
let config = URLSessionConfiguration.default
let session = URLSession(configuration: config)
let task = session.dataTask(with: url) { (data, response, error) in
guard error == nil else {
DispatchQueue.main.async {
print("Google Directions Request Error: \((error!)).")
completionHandler(nil, error)
}
return
}
guard let data = data else {
DispatchQueue.main.async {
let error = NSError(domain: "GoogleDirectionsRequest", code: 0, userInfo: [NSLocalizedDescriptionKey: "Failed to receive data"])
print("Error: \(error).")
completionHandler(nil, error)
}
return
}
do {
guard let json = try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any] else {
DispatchQueue.main.async {
let error = NSError(domain: "GoogleDirectionsRequest", code: 2, userInfo: [NSLocalizedDescriptionKey: "Failed to convert JSON to Dictionary"])
print("Error: \(error).")
completionHandler(nil, error)
}
return
}
guard let status: String = json["status"] as? String, status == "OK" else {
DispatchQueue.main.async {
let error = NSError(domain: "GoogleDirectionsRequest", code: 3, userInfo: [NSLocalizedDescriptionKey: "Google Direction API did not return status OK"])
print("Error: \(error).")
completionHandler(nil, error)
}
return
}
print("Google Direction API response:\n\(json)")
if let routes: [Any] = json["routes"] as? [Any], routes.count > 0, let routes0: [String: Any] = routes[0] as? [String: Any], let overviewPolyline: [String: Any] = routes0["overview_polyline"] as? [String: Any], let points: String = overviewPolyline["points"] as? String {
if let path: GMSPath = GMSPath(fromEncodedPath: points) {
DispatchQueue.main.async {
completionHandler(path, nil)
}
return
} else {
DispatchQueue.main.async {
let error = NSError(domain: "GoogleDirections", code: 5, userInfo: [NSLocalizedDescriptionKey: "Failed to create GMSPath from encoded points string."])
completionHandler(nil, error)
}
return
}
} else {
DispatchQueue.main.async {
let error = NSError(domain: "GoogleDirections", code: 4, userInfo: [NSLocalizedDescriptionKey: "Failed to parse overview polyline's points"])
completionHandler(nil, error)
}
return
}
} catch let error as NSError {
DispatchQueue.main.async {
completionHandler(nil, error)
}
return
}
}
task.resume()
}
}
然后你可以在你的
viewDidLoad
中使用它,就像这样:
@IBOutlet weak var mapView: GMSMapView!
override func viewDidLoad() {
super.viewDidLoad()
let sessionManager = SessionManager()
let start = CLLocationCoordinate2D(latitude: 37.778483, longitude: -122.513960)
let end = CLLocationCoordinate2D(latitude: 37.706753, longitude: -122.418677)
sessionManager.requestDirections(from: start, to: end, completionHandler: { (path, error) in
if let error = error {
print("Something went wrong, abort drawing!\nError: \(error)")
} else {
let polyline = GMSPolyline(path: path!)
polyline.map = self.mapView
let bounds = GMSCoordinateBounds(path: path!)
let cameraUpdate = GMSCameraUpdate.fit(bounds, with: UIEdgeInsets(top: 40, left: 15, bottom: 10, right: 15))
self.mapView.animate(with: cameraUpdate)
}
})
}
希望你觉得它有用。
Google Maps Direction API
,它将返回路线的路径数组。我正在编辑答案以添加Directions API的基本用法。 - Muhammad Abdul Subhan