Refresh the content within Google Maps iOS

Question

I am currently working with the Google Maps API for iOS. I have drawn markers on the maps, but I do not know how to "refresh" (delete markers and redraw new ones) the markers once the user has entered in new data from another class. I try to recall the map view class like this:

This is the code, in another class (GetInfoViewController) that is executed when the user inputs new data

MapViewController *mapVC = [[MapViewController alloc]init];
[mapVC resetMap];

This is what is inside the MapViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    mapView.myLocationEnabled = YES;
    mapView.settings.myLocationButton = YES;
    getpos = [[NSMutableArray alloc]init];

}

- (void)loadView {

    lat = [[NSMutableArray alloc]init];
    lng = [[NSMutableArray alloc]init];
    markers = [[NSMutableArray alloc]init];
    locationManager = [[CLLocationManager alloc] init];
    locationManager.distanceFilter = kCLDistanceFilterNone;
    locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters; // 100 m


    [locationManager startUpdatingLocation];

    GMSCameraPosition *camera = [GMSCameraPosition   cameraWithLatitude:locationManager.location.coordinate.latitude
                                                            longitude:locationManager.location.coordinate.longitude                                                                 zoom:13.2];

    mapView = [GMSMapView mapWithFrame:CGRectZero camera:camera];
    mapView.delegate = self;

    self.view = mapView;
    [mapView clear];
    [self createMarker];

}


- (void) createMarker {

    [lat removeAllObjects];
    [lng removeAllObjects];
    [markers removeAllObjects];

    AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];

    for (int x = 0; x < [appDelegate.geocodedLatArrayGlobal count]; x++) {
        NSNumber *latCoord = [NSNumber numberWithDouble:[[appDelegate.geocodedLatArrayGlobal objectAtIndex:x]doubleValue]];
        [lat addObject: latCoord];
    }

    for (int x = 0; x < [appDelegate.geocodedLngArrayGlobal count]; x++) {
        NSNumber *lngCoord = [NSNumber numberWithDouble:[[appDelegate.geocodedLngArrayGlobal objectAtIndex:x]doubleValue]];
        [lng addObject:lngCoord];
    }

    for (int x = 0; x < [lat count]; x++) {
        double latitude =[[lat objectAtIndex:x]doubleValue];
        double longitude =[[lng objectAtIndex:x]doubleValue];
        CLLocationCoordinate2D position = CLLocationCoordinate2DMake(latitude,longitude) ;
        GMSMarker *marker = [GMSMarker markerWithPosition:position];
        marker.title = @"Title"
        marker.map = mapView;
        [markers addObject:marker];

    }

}

-(void)resetMap{
       NSLog(@"map reset");
       [mapView clear];
       [self createMarker];
}

In GetInfoViewController: Changing the container content to MapViewController

 MapViewController *viewController1 = [self.storyboard instantiateViewControllerWithIdentifier:@"vc1"];
    viewController1.view.frame = self.container.bounds;

    [viewController1 willMoveToParentViewController:self];
    [self.container addSubview:viewController1.view];
    [self addChildViewController:viewController1];
    [viewController1 didMoveToParentViewController:self];
    [UIView beginAnimations:nil context:nil];

    [UIView setAnimationDuration:1];

    [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight  forView:self.container cache:YES];

    [UIView commitAnimations];

Answer 1

To clear markers on Google Maps for ios use the clear function of your GMSMapView instance. Although I suggest you recycle existing markers by changing its properties like its position.

Answer 2

I found the problem: I was allocating and initializing a whole new MapViewController each time the button was pressed

MapViewController *mapVC = [[MapViewController alloc]init];
[mapVC resetMap];

So i created a global variable, only allocated and initialized once in viewDidLoad, to use in my code