当相机位置改变时调用函数答案

【问题标题】：Call a function when camera position changes当相机位置改变时调用函数
【发布时间】：2020-01-27 11:35:51
【问题描述】：

当用户位置和相机位置之间的距离大于 1KM 时，我试图显示 UIButton。我怎样才能实现这个功能？

我尝试了func mapView(_ mapView: GMSMapView, didChange position: GMSCameraPosition) 和func mapView(_ mapView: GMSMapView, willMove gesture: Bool)，但没有得到想要的结果。

感谢您的进一步帮助！

【问题讨论】：

标签： ios swift google-maps swift4

【解决方案1】：

你可以试试

var current: CLLocation?

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

  self.current = locations.last!

}

func mapView(_ mapView: GMSMapView, didChange position: GMSCameraPosition) {

    guard let currentLocation = current else { return } 

    let moved = CLLocation(latitude: position.target.latitude, longitude: position.target.longitude)

    if currentLocation.distance(from: moved) > 1000 {

        self.yourButton.isHidden = false
    } 
    else { //hide it }
}

【讨论】：

感谢为我工作，如果我只想在缩放级别更改时显示按钮，我该怎么做？

【解决方案2】：

我是这样使用它的：

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

    let location: CLLocation = locations.last!
    print("Location: \(location)")

    let camera = GMSCameraPosition.camera(withLatitude: location.coordinate.latitude,
                                          longitude: location.coordinate.longitude,
                                          zoom: self.zoomLevel)

    if let mapView = self.mapView {

        if mapView.isHidden {
            mapView.isHidden = false
            mapView.camera = camera

        } else {
            mapView.animate(to: camera)
        }
    }
    self.calculateDistance(destiLat: Lat Coordinate, destiLongL: Long Coordinate)
}

    //This function calculates the distance between origin and destination

private func calculateDistance(destiLat: CLLocationDegrees, destiLongL: CLLocationDegrees) {

    DispatchQueue.main.async {
        let origin = CLLocation(latitude: self.locationManager.location?.coordinate.latitude ?? 0, longitude: self.locationManager.location?.coordinate.longitude ?? 0)
        let destination = CLLocation(latitude: destiLat, longitude: destiLongL)
        let distanceInMeters = origin.distance(from: destination)

        print(distanceInMeters)

        if distanceInMeters.isLessThanOrEqualTo(60) {

           //You are in range of 60 meters
           //Change the distance and show your button here
        }
    }
}

我不知道这是否是最好的方法，但它对我有用。

【讨论】：

感谢您的回复，您的代码也运行良好；）