iOS - Multiple GMSMarker issue - ios

Question

I am trying to add drag and drop functionality on Google map. Overall it is done but one thing has to fix. That is when I drag and drop GMSMarker on Google map pervious GMSMarker still exist and another (wherever I dropped it) GMSMarker created new. But I want only one GMSMarker. How to remove pervious/ old GMSMarker. Any suggestion will be Great. Thanks in advance.
Code :
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {
// Mumbabi address
GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:19.01761470
longitude:72.85616440
zoom:4];
// mapView = [GMSMapView mapWithFrame:CGRectZero camera:camera];
mapViewGMS.camera=camera;
mapViewGMS.delegate = self;
CLLocationCoordinate2D position = CLLocationCoordinate2DMake([#"19.01761470" floatValue ], [#"72.85616440" floatValue]);
GMSMarker *marker = [GMSMarker markerWithPosition:position];
marker.title = #"This is your current location";
[marker setDraggable: YES];
marker.appearAnimation=0.2f;
marker.map = mapViewGMS;
}
- (void)mapView:(GMSMapView *)mapView didEndDraggingMarker:(GMSMarker *)marker
{
NSLog(#">>> mapView:didEndDraggingMarker: %#", [marker description]);
NSString *lati=[NSString stringWithFormat:#"%f",marker.position.latitude];
NSString *longi=[NSString stringWithFormat:#"%f",marker.position.longitude];
NSString * urpPath = [NSString stringWithFormat:#"http://maps.googleapis.com/maps/api/geocode/json?latlng=%#,%#&sensor=true",lati,longi];
[[ConnectionManager connectionManagerSharedInstance]sendPOSTRequestForPath:urpPath data:nil timeoutInterval:50 completion:^(NSDictionary *dictionary, NSError *error) {
if(!error){
if(dictionary){
if([dictionary valueForKey:#"results"] == nil || [[dictionary valueForKey:#"status"]isEqualToString:#"ZERO_RESULTS"]){
dispatch_async(dispatch_get_main_queue(), ^{
[self presentViewController:[ViewUtilities showAlert:#"Message!!" :#"Unable to fetch this location, May be this is an invalid loation. However Please Check your Internet Connection, and re- run this app."] animated:YES completion:nil];
});
}
else
{
strUserCurrentAddressAuto=[NSString stringWithFormat:#"%#",[[[dictionary valueForKey:#"results"] objectAtIndex:0] valueForKey:#"formatted_address"]];
NSLog(#"\n\n ***** Great User address found,---> %# *****\n\n",strUserCurrentAddressAuto);
dispatch_async(dispatch_get_main_queue(), ^{
//[self.automaticallySearchBtn setTitle:self.fullSourceAddress forState:UIControlStateNormal];
UIAlertController *alert= [UIAlertController alertControllerWithTitle:strUserCurrentAddressAuto message:#"Select this Loaction for ?"
preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction *pick = [UIAlertAction actionWithTitle:#"Pick Up Location" style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action) {
labelSourceLocation.text=strUserCurrentAddressAuto;
// nil marker title (old title it is : This is your current location)
marker.title = nil;
locationSource = [[CLLocation alloc] initWithLatitude:marker.position.latitude longitude:marker.position.longitude];
if (locationSource !=nil && locationDest!=nil) {
CLLocationDistance dist = [locationSource distanceFromLocation:locationDest]/1000;
NSLog(#"\n\n **** Using Drag and drop Poin, Total distance in K.M. => %f",dist);
totalDistance = [NSString stringWithFormat:#"%f",dist];
}
[alert dismissViewControllerAnimated:YES completion:nil];
}];
UIAlertAction *drop = [UIAlertAction actionWithTitle:#"Drop Location" style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action) {
labelDropLocation.text=strUserCurrentAddressAuto;
// nil marker title (old title it is : This is your current location)
marker.title = nil;
locationDest = [[CLLocation alloc] initWithLatitude:marker.position.latitude longitude:marker.position.longitude];
if (locationSource !=nil && locationDest!=nil) {
CLLocationDistance dist = [locationSource distanceFromLocation:locationDest]/1000;
NSLog(#"\n\n **** Using Drag and drop Poin, Total distance in K.M. => %f",dist);
totalDistance = [NSString stringWithFormat:#"%f",dist];
}
[alert dismissViewControllerAnimated:YES completion:nil];
}];
[alert addAction:pick];
[alert addAction:drop];
[self presentViewController:alert animated:YES completion:nil];
});
}
}
}
}];
}

Answer 1

You need to remove the previous marker placed over mapView, it is the most preferable solution in this kind of situation or accordingly.
To Clear mapView:
[mapView clear];
Use below code to drag and drop marker excluding previous one:
-(void)mapView:(GMSMapView *)mapView didEndDraggingMarker:(GMSMarker *)marker{
CLLocationCoordinate2D pos;
pos.latitude = marker.position.latitude;
pos.longitude = marker.position.longitude;
// this removes the previous markers
[mapView clear];
// this method adds the marker where user dropped it
[self placeMarker:pos.latitude withLong:pos.longitude];
}
// helping method
-(void) placeMarker:(float)lat withLong:(float)lon{
CLLocationCoordinate2D pinlocation;
pinlocation.latitude = lat;
pinlocation.longitude = lon;
GMSMarker *marker = [[GMSMarker alloc] init];
[marker setDraggable: YES];
marker.position = pinlocation;
marker.title = #"Hi";
marker.snippet = #"New marker";
marker.appearAnimation = kGMSMarkerAnimationPop;
marker.icon = [GMSMarker markerImageWithColor:[UIColor redColor]];
marker.map = self.mapView;
// this always visible marker info window, comment if do not need
[self.mapView setSelectedMarker:marker];
}
Update:
To remove specific marker on map, just keep the reference of that marker object and later set it to nil see below code:
// declare marker globally to declare its scope to entire class.
GMSMarker *markerToRemoveLater;
// initialization and configuration
markerToRemoveLater = [[GMSMarker alloc] init];
// set nil where you want to remove specific marker
markerToRemoveLater.map = nil;

Answer 2

I had the same issue when I was working on Gmaps. I wanted to clear the marker without using [map clear]. I came up with this solution.
-(void)mapView:(GMSMapView *)mapView didEndDraggingMarker:(GMSMarker *)marker{
CLLocationCoordinate2D pos;
pos.latitude = marker.position.latitude;
pos.longitude = marker.position.longitude;
// this removes the previous marker from map
marker.map = nil;
// ** Give your marker new position from CLLocationCoordinate2D
//Then
[self mapView:mapViewGoog didTapAtCoordinate:marker.position];
}
- (void)mapView:(GMSMapView *)mapView didTapAtCoordinate:(CLLocationCoordinate2D)coordinate {
[self addMarkerInTheMapView:coordinate];
}
-(void)addMarkerInTheMapView:(CLLocationCoordinate2D)coordinate{
markerMYLocation.map = nil;
markerMYLocation = [[GMSMarker alloc] init];
//Your code here.
markerMYLocation.map = mapView;
}