如何跟踪用户的位置并显示使用Google Maps ios SDK的路径 [英] How to track a user's location and display the path travelled using Google Maps ios SDK

问题描述

目前我正在构建一个ios应用程序，并且希望实现一个功能，用户的位置显示在Google Map视图上，以及当他们移动多段线显示的用户到目前为止走过的路径时。这显然需要实时发生。

到目前为止，我已初始化Google地图视图，并可以使用 observeValueForKeyPath 显示用户的当前位置。功能。

我认为最好的方法是创建一个GMSMutablePath对象，每次添加用户的当前位置时将相机更新映射到新位置，然后从该路径创建折线。我使用的代码如下：

   - （void）observeValueForKeyPath：（NSString *）keyPath ofObject：（id ）对象变化：（的NSDictionary *）变化上下文：（无效*）上下文
 {
如果（[的keyPath isEqualToString：@ myLocation]&安培;&安培; [对象isKindOfClass：[GMSMapView中类]]） 
 {
 [self.myMapView animateToCameraPosition：[GMSCameraPosition cameraWithLatitude：self.myMapView.myLocation.coordinate.latitude 
经度：self.myMapView.myLocation.coordinate.longitude 
变焦：18 ]]; 
 
 
 [trackedPath addCoordinate：CLLocationCoordinate2DMake（self.myMapView.myLocation.coordinate.latitude，self.myMapView.myLocation.coordinate.longitude）]; 
 GMSPolyline * testPoly = [GMSPolyline polylineWithPath：trackedPath]; 
 testPoly.strokeWidth = 8; 
 testPoly.strokeColor = [UIColor redColor]; 
 testPoly.map = myMapView; 
 
 
  

这不会在地图上产生任何折线所以任何帮助/建议将非常感谢！

解决方案

   - （void）locationManager ：（CLLocationManager *）经理didUpdateToLocation：（CLLocation *）newLocation fromLocation：（CLLocation *）oldLocation {的NSString * pointString = [NSString的stringWithFormat：@ ％F，％F，newLocation.coordinate.latitude，newLocation.coordinate.longitude] ; 
 [self.points addObject：pointString]; 
 GMSMutablePath * path = [GMSMutablePath path]; 
为（INT I = 0; I< self.points.count;我++）
 {
的NSArray * latlongArray = [[self.points objectAtIndex：ⅰ] componentsSeparatedByCharactersInSet：[NSCharacterSet characterSetWithCharactersInString：@ ]]; 
 
 [路径addLatitude：[[latlongArray objectAtIndex：0] doubleValue] longitude：[[latlongArray objectAtIndex：1] doubleValue]]; 
 
 
 if（self.points.count> 2）
 {
 GMSPolyline * polyline = [GMSPolyline polylineWithPath：path]; 
 polyline.strokeColor = [UIColor blueColor]; 
 polyline.strokeWidth = 5.f; 
 polyline.map = mapView_; 
 self.view = mapView_; 
}} 
  

I'm currently building an ios app and I'm hoping to implement a function where the user's location is displayed on a Google Map view and when they move a polyline show's the path that has been travelled by the user so far. This obviously needs to happen in realtime.

So far I've initialised a Google Maps view and can display the user's current location using the observeValueForKeyPath function. The view and location marker update as the user moves.

I figured the best way to do this would be to create a GMSMutablePath object that adds the user's current location every time the map camera updates to the new location and then create a polyline from that path. The code I've used for this is below:

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if ([keyPath isEqualToString:@"myLocation"] && [object isKindOfClass:[GMSMapView class]])
    {
        [self.myMapView animateToCameraPosition:[GMSCameraPosition cameraWithLatitude:self.myMapView.myLocation.coordinate.latitude
                                                                                 longitude:self.myMapView.myLocation.coordinate.longitude
                                                                                      zoom:18]];


        [trackedPath addCoordinate:CLLocationCoordinate2DMake(self.myMapView.myLocation.coordinate.latitude, self.myMapView.myLocation.coordinate.longitude)];
        GMSPolyline *testPoly = [GMSPolyline polylineWithPath:trackedPath];
        testPoly.strokeWidth = 8;
        testPoly.strokeColor = [UIColor redColor];
        testPoly.map = myMapView;
    }
}

This doesn't produce any polyline on the map in practice so any help/advice would be much appreciated!

解决方案

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation{  NSString *pointString=[NSString    stringWithFormat:@"%f,%f",newLocation.coordinate.latitude,newLocation.coordinate.longitude];
    [self.points addObject:pointString];
GMSMutablePath *path = [GMSMutablePath path];
for (int i=0; i<self.points.count; i++)
{           
  NSArray *latlongArray = [[self.points   objectAtIndex:i]componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@","]];

[path addLatitude:[[latlongArray objectAtIndex:0] doubleValue] longitude:[[latlongArray objectAtIndex:1] doubleValue]];
 }

if (self.points.count>2)
{
    GMSPolyline *polyline = [GMSPolyline polylineWithPath:path];
    polyline.strokeColor = [UIColor blueColor];
    polyline.strokeWidth = 5.f;
    polyline.map = mapView_;
    self.view = mapView_;
}}

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