ios - GMSMapView myLocation 未提供实际位置

Question

我有一个 GMSMapView 正确加载并在我的 View Controller 中工作

我无法做的是围绕我的位置设置 GMSCameraPosition

这是我的代码:

mapView_.myLocationEnabled = YES;
CLLocation* myLoc = [mapView_ myLocation];
GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:myLoc.coordinate.latitude
                                                        longitude:myLoc.coordinate.longitude
                                                             zoom:4];
[mapView_ setCamera:camera];

GPS 已启用并且应用程序具有所有需要的权限，但 myLocation 返回 nil CLLocation，因此 cameraWithLatitude:longitude:zoom: 获取 0 0 坐标并显示非洲而不是我的实际位置(不在非洲 :) )

Answer 1

来自官方 Google Maps iOS SDK 文档:

• (BOOL) myLocationEnabled [read, write, assign] Controls whether the My Location dot and accuracy circle is enabled.

Defaults to NO.

• (CLLocation*) myLocation [read, assign] If My Location is enabled, reveals where the user location dot is being drawn.

If it is disabled, or it is enabled but no location data is available, this will be nil. This property is observable using KVO.

因此，当您设置 mapView_.myLocationEnabled = YES; 时，它只会告诉 mapView 只有在您为 指定位置值时才显示蓝点>我的位置 属性。 Google 的示例代码显示了如何使用 KVO 方法观察用户位置。(推荐)您还可以实现 CLLocationManagerDelegate 方法，以更新 mapView。

-(void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
    [mapView animateToLocation:newLocation.coordinate];
    // some code...
}

以下是来自 google maps 示例代码的代码，介绍如何使用 KVO 更新用户位置。

// in viewDidLoad method...
// Listen to the myLocation property of GMSMapView.
  [mapView_ addObserver:self
             forKeyPath:@"myLocation"
                options:NSKeyValueObservingOptionNew
                context:NULL];
// Ask for My Location data after the map has already been added to the UI.
  dispatch_async(dispatch_get_main_queue(), ^{
    mapView_.myLocationEnabled = YES;
  });

- (void)observeValueForKeyPath:(NSString *)keyPath
                      ofObject:(id)object
                        change:(NSDictionary *)change
                       context:(void *)context {
  if (!firstLocationUpdate_) {
    // If the first location update has not yet been recieved, then jump to that
    // location.
    firstLocationUpdate_ = YES;
    CLLocation *location = [change objectForKey:NSKeyValueChangeNewKey];
    mapView_.camera = [GMSCameraPosition cameraWithTarget:location.coordinate
                                                     zoom:14];
  }
}