Google Maps markers not removing iOS

问题

I'm running a thread to fetch drivers location every 10 seconds and want to remove the added markers from the map but it doesn't work..

My code:

-(void)APiResponse:(id)returnJson
{        
        [googleMapsDriverPin setMap:nil];
        googleMapsDriverPin = nil;

        NSMutableArray *driverPins = [[NSMutableArray alloc]init];
        for (int x = 0; x < [[returnJson valueForKey:@"drivers"] count]; x++) {
            CLLocation *driverLocations = [[CLLocation alloc]initWithLatitude:[[[[returnJson valueForKey:@"drivers"] objectAtIndex:x] valueForKey:@"driver_latitude"] doubleValue] longitude:[[[[detail valueForKey:@"drivers"] objectAtIndex:x] valueForKey:@"driver_longitude"] doubleValue]];
            [driverPins addObject:driverLocations];
        }

        for (CLLocation *newLocation in driverPins) {
            googleMapsDriverPin = [[GMSMarker alloc] init];
            [googleMapsDriverPin setPosition:newLocation.coordinate];
            [googleMapsDriverPin setAnimated:YES];
            [googleMapsDriverPin setTitle:@"title"];
            [googleMapsDriverPin setSnippet:@"snippet"];
            [googleMapsDriverPin setIcon:[GMSMarker markerImageWithColor:[UIColor blackColor]]];
            [googleMapsDriverPin setMap:googleMaps];
         }
}

It just keeps adding and adding every 10 seconds and not removing, please help! Thanks!

回答1:

Its a kind of quick and dirty option but if you wanted to go that way GMSMarker has a userData property which you could use to tag the driver pins

- (void)apiResponse:(id)returnJson
{        
    for (GMSMarker *pin in self.googleMaps.markers) {
        if (pin.userData == @"Driver Pin"){ 
            pin.map = nil; 
        }
    }

    ...

    for (CLLocation *newLocation in driverPins) {
        googleMapsDriverPin = [[GMSMarker alloc] init];
        ...
        [googleMapsDriverPin setUserData:@"Driver Pin"];
    }
}

Update:

[self.googleMapsView clear];

回答2:

On the based on pin id you can also delete pin. Here deletePinId integer is for selected pin id.

for(GMSMarker *pin in self.mapView_.markers) {
NSLog(@"pin.userData : %@",pin.userData);
int pinId1 = [[pin.userData valueForKey:@"pin_id"] integerValue];
if(deltePinId == pinId1 ){
    pin.map = nil;
 }

}

回答3:

you currently only store ONE marker, but you want to add N markers -- so (as saxon said) you need an array to hold all the pins :)

@interface YouClass

...

@property(nonatomic, retain) NSMutableArray *googleMapsDriverPins;
@end

@implementation YourClass

...

-(void)APiResponse:(id)returnJson
{    
    for(GMSMarker *pin in self.googleMapsDriverPins) {
        pin.map = nil;
    }    
    self.googleMapsDriverPins = nil;

    NSMutableArray *driverPins = [[NSMutableArray alloc]init];
    for (int x = 0; x < [[returnJson valueForKey:@"drivers"] count]; x++) {
        CLLocation *driverLocations = [[CLLocation alloc]initWithLatitude:[[[[returnJson valueForKey:@"drivers"] objectAtIndex:x] valueForKey:@"driver_latitude"] doubleValue] longitude:[[[[detail valueForKey:@"drivers"] objectAtIndex:x] valueForKey:@"driver_longitude"] doubleValue]];
        [driverPins addObject:driverLocations];
    }

    self.googleMapsDriverPins = [NSMutableArray arrayWithCapacity:driverPins.count];
    for (CLLocation *newLocation in driverPins) {
        GMSMarker *googleMapsDriverPin = [[GMSMarker alloc] init];
        [googleMapsDriverPin setPosition:newLocation.coordinate];
        [googleMapsDriverPin setAnimated:YES];
        [googleMapsDriverPin setTitle:@"title"];
        [googleMapsDriverPin setSnippet:@"snippet"];
        [googleMapsDriverPin setIcon:[GMSMarker markerImageWithColor:[UIColor blackColor]]];
        [googleMapsDriverPin setMap:googleMaps];
        [self.googleMapsDriverPins addObject:googleMapsDriverPin];
     }
 }
 @end

回答4:

It looks like you have a loop adding multiple drivers, each of which assigns to the member variable googleMapsDriverPin. Then next time it removes the googleMapsDriverPin - but that will only be the last pin you added, not all of them.

For this to work you would need to add each marker inside your loop to an array, and then remove all of them from the map on your next update.

回答5:

In Swift 2:

Create an outlet for your map:

@IBOutlet weak var mapView: GMSMapView!

Create an array to store all markers

var markers = [GMSMarker]()

Create markers like this:

    func funcName() {    
        let position = CLLocationCoordinate2DMake(lat, lon)
        let marker = GMSMarker(position: position)

        for pin: GMSMarker in self.markers {
             if pin.userData as! String == "from" {
                   pin.map = nil
             }
        }

        marker.icon = UIImage(named: "navigation-red")
        marker.userData = "from"
        marker.map = self.mapView
        self.markers.append(marker)
    }

You can set the userData property to anything you want and later on use that string to delete that marker.When the funcName function is executed, all markers with userData as "from" are removed from the map.Let me know if you have any queries.

来源：https://stackoverflow.com/questions/16559688/google-maps-markers-not-removing-ios