GMSMapView更新相机位置，以便在导航期间始终显示朝向顶部的方向

Question

我已经使用了方位属性来在mapview上旋转相机，但无法定位相机，因此它始终将导航显示在顶部。

下面是google map应用的屏幕截图，该应用会在导航过程中自动自动旋转，以便始终显示指向顶部的路线。

下面是我的应用的屏幕截图，该屏幕始终显示任意方向的路线。

我使用下面的代码旋转摄像机，但实际上不知道如何获得始终在顶部显示的所需方位角。

            let cameraPosition = GMSCameraPosition.camera(withTarget: currentLocation, zoom: self.camera.zoom, bearing: MyRide.shared.bearing, viewingAngle: 45)
        let cameraUpdate = GMSCameraUpdate.setCamera(cameraPosition)

        CATransaction.begin()
        CATransaction.setValue(1.0, forKey: kCATransactionAnimationDuration)
        self.animate(with: cameraUpdate)
        CATransaction.commit()

Answer 1

let camera = GMSCameraPosition.camera(withTarget: CLLocationCoordinate2DMake(startLat, startLong), zoom: 17, bearing: getBearingBetweenTwoPoints(point1: CLLocationCoordinate2DMake(startLat, startLong), point2:CLLocationCoordinate2DMake(endLat, endLong)), viewingAngle: 45)

使用下面的方位角计算方法，您将获得所需的起点到终点的方位角。

func degreesToRadians(degrees: Double) -> Double { return degrees * .pi / 180.0 }
func radiansToDegrees(radians: Double) -> Double { return radians * 180.0 / .pi }

func getBearingBetweenTwoPoints(point1 : CLLocationCoordinate2D, point2 : CLLocationCoordinate2D) -> Double {

    let lat1 = degreesToRadians(degrees: point1.latitude)
    let lon1 = degreesToRadians(degrees: point1.longitude)

    let lat2 = degreesToRadians(degrees: point2.latitude)
    let lon2 = degreesToRadians(degrees: point2.longitude)

    let dLon = lon2 - lon1

    let y = sin(dLon) * cos(lat2)
    let x = cos(lat1) * sin(lat2) - sin(lat1) * cos(lat2) * cos(dLon)
    let radiansBearing = atan2(y, x)

    return radiansToDegrees(radians: radiansBearing)
}

如果要动态获取路径的方位，则必须根据需要获取当前路线的终点。