topic Re: AGSLocationDisplay refresh in ArcGIS Runtime SDK for iOS Questions

AGSLocationDisplay refresh

QKunZhu — Sat, 11 Dec 2021 21:20:43 GMT

What I am trying to do is, when you press a button, the app auto pan and zoom to current location. Then I can pan the map to other place, and when I press that button again, it will still bring me to my current location (auto pan and zoom).

My problem is, when I first press the button, it works as i expected. Then I move to other place on the map, and when i press the button again, it does not auto pan and zoom to my current location.

Code is below:

- (void)viewDidLoad {
    [super viewDidLoad];

     // add map layers
     ... ...

     
     self.mapView.locationDisplay.autoPanMode = AGSLocationDisplayAutoPanModeCompassNavigation;
     self.mapView.locationDisplay.navigationPointHeightFactor = 0.5;
     [self.mapView.locationDisplay addObserver:self forKeyPath:@"location" options:NSKeyValueObservingOptionNew context:NULL];
} 

- (IBAction)showCurrentLocation:(id)sender {

    [self.mapView.locationDisplay startDataSource];
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
   
    if ([keyPath isEqual:@"location"]) {
       
        // creating graphics on current location
          ... ...

        [self.mapView.locationDisplay stopDataSource];
    }
}

Re: AGSLocationDisplay refresh

MengyiGuo — Thu, 18 Jun 2015 18:11:26 GMT

In your observeValueForKeyPath method, you should not stopDataSource. That will stop the location and you will not be able to display it. I modified your code as follows:

-(void) mapViewDidLoad:(AGSMapView*)mapView {

// Enable location display on the map

[self.mapView.locationDisplay startDataSource];

self.mapView.locationDisplay.autoPanMode = AGSLocationDisplayAutoPanModeDefault;

[self.mapView zoomToScale:500.0 animated:true];

}

- (void)viewDidUnload {

//Stop the GPS, undo the map rotation (if any)

if(self.mapView.locationDisplay.dataSourceStarted){

[self.mapView.locationDisplay stopDataSource];

self.mapView.rotationAngle = 0;

}

self.mapView = nil;

}

- (IBAction)showCurrentLocation:(id)sender {

if(!self.mapView.locationDisplay.dataSourceStarted)

[self.mapView.locationDisplay startDataSource];

self.mapView.locationDisplay.autoPanMode = AGSLocationDisplayAutoPanModeDefault;

}

Re: AGSLocationDisplay refresh

QKunZhu — Tue, 30 Jun 2015 03:06:14 GMT

Thank you so much! It works.