如何将Google Map动画到当前标记位置并在Swift中绘制线条

Question

我正在从Firestore获取位置，并成功在Google Map的特定位置上显示了标记，但是当我在Simulator中运行应用程序时遇到的问题是它无法动画显示当前标记位置。而且我不知道如何在标记之间绘制路线。请帮忙吗？

这是从Firestore快速获取位置的代码。

for document in snapshot!.documents {
print(document.data())
let marker = GMSMarker()

self.location.append(Location(trackingData: document.data()))

print(self.location)

let latitude = document.data()["Latitude"] ?? 0
print(latitude)
let longitude = document.data()["longitude"] ?? 0
print(longitude)

    marker.position = CLLocationCoordinate2D(latitude: latitude as! CLLocationDegrees , longitude: longitude as! CLLocationDegrees)
    marker.map = self.mapView
    marker.userData = self.location
    marker.icon = UIImage(named: "marker")
    print("Data stored in marker \(marker.userData!)")
 }

Answer 1

您可以使用GMSCoordinateBounds

参考：https://stackoverflow.com/a/45169325/8447312

for循环之前有一个bounds对象：

var bounds = GMSCoordinateBounds()

然后在for循环中，将每个标记的位置包含在bounds对象中：

var bounds = GMSCoordinateBounds()

for document in snapshot!.documents {
    print(document.data())
    let marker = GMSMarker()

    self.location.append(Location(trackingData: document.data()))
    let latitude = document.data()["Latitude"] ?? 0
    let longitude = document.data()["longitude"] ?? 0

    marker.position = CLLocationCoordinate2D(latitude: latitude as! CLLocationDegrees , longitude: longitude as! CLLocationDegrees)
    marker.map = self.mapView
    marker.userData = self.location
    marker.icon = UIImage(named: "marker")

    //include position for each marker
    bounds = bounds.includingCoordinate(marker.position)
 }

 //when your loop is completed you included all your marker's coordinate in your bounds now, you need to animate:

 mapView.animate(with: GMSCameraUpdate.fit(bounds, with: UIEdgeInsets(top: 20.0, left: 20.0, bottom: 20.0, right: 20.0)))

我给每侧20个插图，您可以将其更改为您想要的值。

关于绘图线，请尝试以下操作：

在创建边界的上方创建路径：

let path = GMSMutablePath()

然后在for循环中，将每个标记的位置添加到此路径中，就像对边界所做的那样：

path.add(marker.position)

在为mapView设置动画之前，先创建如下方向：

let directions = GMSPolyline(path: path)
directions.strokeWidth = 1.0
directions.map = mapView

完整代码（添加了路径）：

var bounds = GMSCoordinateBounds()
var path = GMSMutablePath()

for document in snapshot!.documents {
    print(document.data())
    let marker = GMSMarker()

    self.location.append(Location(trackingData: document.data()))
    let latitude = document.data()["Latitude"] ?? 0
    let longitude = document.data()["longitude"] ?? 0

    marker.position = CLLocationCoordinate2D(latitude: latitude as! CLLocationDegrees , longitude: longitude as! CLLocationDegrees)
    marker.map = self.mapView
    marker.userData = self.location
    marker.icon = UIImage(named: "marker")

    bounds = bounds.includingCoordinate(marker.position)
    path.add(marker.position)
 }

 let directions = GMSPolyline(path: path)
 directions.strokeWidth = 1.0
 directions.map = mapView

 mapView.animate(with: GMSCameraUpdate.fit(bounds, with: UIEdgeInsets(top: 20.0, left: 20.0, bottom: 20.0, right: 20.0)))