objective-c - 百度地图定位获取到的经纬度是0

Question

用百度地图api定位，拿到的经纬度一直是0，代码如下

BMKLocationService *locationService = [[BMKLocationService alloc]init];
locationService.delegate = self;
[locationService startUserLocationService];
BMKUserLocation *location = locationService.userLocation;