在 Swift 中显示 GoogleMaps？

我的代码：

var camera = GMSCameraPosition.cameraWithLatitude(currentLocation.latitude, longitude: currentLocation.longitude, zoom: 12) 
//latitude, longitude like :31.230416 and 121.473701.
let map = GMSMapView(frame: CGRectZero)
map.delegate = self
map.camera = camera
self.view = map

效果很好！像这样：

但是当我创建新视图时：@IBOutlet weak var mapView: UIView!

然后更改这一行：self.view = map to self.mapView = map

它对我不起作用，我得到一个空白视图。

I fixed it by go to my view (view display map), then change class my view to GMSMapView.