用箭头替换GMSMapView中的蓝点 - Swift

Question

我将Google SDK用于iOS8应用程序（Swift）。 我想用箭头根据智能手机的方向旋转来替换GMSMapView中的蓝点（我的位置）。 我怎么能这样做？

编辑：

我设法看到了我的箭，但我有三个问题：

1：箭头被剪切，我找不到放大区域

2：箭头的位置并不完全在我的位置我通过删除来解决这个问题＆＃34; 0,5＆＃34; ： 的

CGContextTranslateCTM(context, size.width, size.height)

3：箭头的方向与原始对称我通过添加＆＃34; - ＆＃34;解决了这个问题。之前＆＃34;度＆＃34; ： 的

CGContextRotateCTM(context, CGFloat(DegreesToRadians(Double(-degrees))))

如何解决这些问题？

Answer 1

如果您使用的是Google地图iOS SDK，则似乎有no way to replace默认的用户位置图标。但是，默认图标已经有一个箭头指示用户的方向（只需拨打mapView.myLocationEnabled = true）。

解决方法是在用户的当前位置放置标记，并根据标题更改标记图像。

示例代码（the full source code）：

    func RadiansToDegrees(radians: Double) -> Double {
        return radians * 180.0/M_PI
    }

    func DegreesToRadians(degrees: Double) -> Double {
        return degrees * M_PI / 180.0
    }

    var GeoAngle = 0.0
    var locationManager = CLLocationManager()
    var marker = GMSMarker()

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        var camera = GMSCameraPosition.cameraWithLatitude(-33.86,
            longitude: 151.20, zoom: 6)
        var mapView = GMSMapView.mapWithFrame(CGRectZero, camera: camera)
        self.view = mapView

        marker.map = mapView

        locationManager.delegate = self
        locationManager.requestAlwaysAuthorization()
        locationManager.startUpdatingLocation()
        locationManager.startUpdatingHeading()
    }

    func locationManager(manager: CLLocationManager!, didUpdateToLocation newLocation: CLLocation!, fromLocation oldLocation: CLLocation!) {
        var camera = GMSCameraPosition.cameraWithLatitude(newLocation.coordinate.latitude,
            longitude: newLocation.coordinate.longitude, zoom: 15)
        (self.view as GMSMapView).animateToCameraPosition(camera)

        GeoAngle = self.setLatLonForDistanceAndAngle(newLocation)
        marker.position = newLocation.coordinate
    }

    func locationManager(manager: CLLocationManager!, didUpdateHeading newHeading: CLHeading!) {
        var direction = -newHeading.trueHeading as Double
        marker.icon = self.imageRotatedByDegrees(CGFloat(direction), image: UIImage(named: "arrow.png")!)
    }


    func imageRotatedByDegrees(degrees: CGFloat, image: UIImage) -> UIImage{
        var size = image.size

        UIGraphicsBeginImageContext(size)
        var context = UIGraphicsGetCurrentContext()

        CGContextTranslateCTM(context, 0.5*size.width, 0.5*size.height)
        CGContextRotateCTM(context, CGFloat(DegreesToRadians(Double(degrees))))

        image.drawInRect(CGRect(origin: CGPoint(x: -size.width*0.5, y: -size.height*0.5), size: size))
        var newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return newImage
    }

    func setLatLonForDistanceAndAngle(userLocation: CLLocation) -> Double {
        var lat1 = DegreesToRadians(userLocation.coordinate.latitude)
        var lon1 = DegreesToRadians(userLocation.coordinate.longitude)

        var lat2 = DegreesToRadians(37.7833);
        var lon2 = DegreesToRadians(-122.4167);

        var dLon = lon2 - lon1;

        var y = sin(dLon) * cos(lat2);
        var x = cos(lat1) * sin(lat2) - sin(lat1) * cos(lat2) * cos(dLon);
        var radiansBearing = atan2(y, x);
        if(radiansBearing < 0.0)
        {
            radiansBearing += 2*M_PI;
        }

        return radiansBearing;
    }

关键步骤是根据来自func locationManager(manager: CLLocationManager!, didUpdateHeading newHeading: CLHeading!)方法的程度更改图像。

您还需要确保在NSLocationAlwaysUsageDescription文件中添加NSLocationWhenInUseUsageDescription和info.plist。

Answer 2

iOS中Google地图的默认蓝色图标可以通过设置隐藏

mapView.myLocationEnabled = FALSE;