show direction button in swift mapView using googleMaps api

I googled for this but I found nothing. so I did it manually. by overriding 'didTapMarker' I added these two buttons:

    func mapView(mapView: GMSMapView, didTapMarker marker: GMSMarker) -> Bool {
            if marker.title != nil {

                let mapViewHeight = mapView.frame.size.height
                let mapViewWidth = mapView.frame.size.width


                let container = UIView()
                container.frame = CGRectMake(mapViewWidth - 100, mapViewHeight - 63, 65, 35)
                container.backgroundColor = UIColor.whiteColor()
                self.view.addSubview(container)

                let googleMapsButton = CustomButton()
                googleMapsButton.setTitle("", forState: .Normal)
                googleMapsButton.setImage(UIImage(named: "googlemaps"), forState: .Normal)
                googleMapsButton.setTitleColor(UIColor.blueColor(), forState: .Normal)
                googleMapsButton.frame = CGRectMake(mapViewWidth - 80, mapViewHeight - 70, 50, 50)
                googleMapsButton.addTarget(self, action: "markerClick:", forControlEvents: .TouchUpInside)
                googleMapsButton.gps = String(marker.position.latitude) + "," + String(marker.position.longitude)
                googleMapsButton.title = marker.title
                googleMapsButton.tag = 0

                let directionsButton = CustomButton()

                directionsButton.setTitle("", forState: .Normal)
                directionsButton.setImage(UIImage(named: "googlemapsdirection"), forState: .Normal)
                directionsButton.setTitleColor(UIColor.blueColor(), forState: .Normal)
                directionsButton.frame = CGRectMake(mapViewWidth - 110, mapViewHeight - 70, 50, 50)
                directionsButton.addTarget(self, action: "markerClick:", forControlEvents: .TouchUpInside)
                directionsButton.gps = String(marker.position.latitude) + "," + String(marker.position.longitude)
                directionsButton.title = marker.title
                directionsButton.tag = 1
                self.view.addSubview(googleMapsButton)
                self.view.addSubview(directionsButton)
            }
            return true
        }

func markerClick(sender: CustomButton) {
        let fullGPS = sender.gps
        let fullGPSArr = fullGPS!.characters.split{$0 == ","}.map(String.init)

        let lat1 : NSString = fullGPSArr[0]
        let lng1 : NSString = fullGPSArr[1]


        let latitude:CLLocationDegrees =  lat1.doubleValue
        let longitude:CLLocationDegrees =  lng1.doubleValue

        if (UIApplication.sharedApplication().openURL(NSURL(string:"comgooglemaps://")!)) {
            if (sender.tag == 1) {
                UIApplication.sharedApplication().openURL(NSURL(string:
                    "comgooglemaps://?saddr=&daddr=\(latitude),\(longitude)&directionsmode=driving")!)
            } else if (sender.tag == 0) {
                UIApplication.sharedApplication().openURL(NSURL(string:
                    "comgooglemaps://?center=\(latitude),\(longitude)&zoom=14&views=traffic")!)
            }

        } else {
            let regionDistance:CLLocationDistance = 10000
            let coordinates = CLLocationCoordinate2DMake(latitude, longitude)
            let regionSpan = MKCoordinateRegionMakeWithDistance(coordinates, regionDistance, regionDistance)
            var options = NSObject()
            if (sender.tag == 1) {
                options = [
                    MKLaunchOptionsMapCenterKey: NSValue(MKCoordinate: regionSpan.center),
                    MKLaunchOptionsMapSpanKey: NSValue(MKCoordinateSpan: regionSpan.span),
                    MKLaunchOptionsDirectionsModeKey: MKLaunchOptionsDirectionsModeDriving
                ]
            } else if (sender.tag == 0) {
                options = [
                    MKLaunchOptionsMapCenterKey: NSValue(MKCoordinate: regionSpan.center),
                    MKLaunchOptionsMapSpanKey: NSValue(MKCoordinateSpan: regionSpan.span)
                ]
            }

            let placemark = MKPlacemark(coordinate: coordinates, addressDictionary: nil)
            let mapItem = MKMapItem(placemark: placemark)
            mapItem.name = sender.title
            mapItem.openInMapsWithLaunchOptions(options as? [String : AnyObject])
        }
    }

two buttons are added in the bottom right of the mapView and after tapping them, the googleMaps app (if exists) will be opened. thanks for vote down :(

Custom Button class:

class CustomButton: UIButton {
    var gps = ""
    override func awakeFromNib() {
        super.awakeFromNib()

        //TODO: Code for our button
    }
}

i using code for swift version 3. and I change contain view that i add subview of UIImageView to containView.

Adding two button on google map. and I use code of Lithium with on the top.

func mapView(_ mapView: GMSMapView, didTap marker: GMSMarker) -> Bool {

    if marker.title != nil {
        let mapViewHeight = mapView.frame.size.height
        let mapViewWidth = mapView.frame.size.width


        let container = UIView()
        container.frame = CGRect.init(x: mapViewWidth - 100, y: mapViewHeight - 63, width: 65, height: 35)
        container.backgroundColor = UIColor.white
        self.view.addSubview(container)

        let googleMapsButton = CustomButton()
        googleMapsButton.setTitle("", for: .normal)
        googleMapsButton.setImage(UIImage(named: "googlemaps")?.resizableImage(withCapInsets: UIEdgeInsets.init(top: 0, left: 0, bottom: 50, right: 50)),for: .normal)
        googleMapsButton.setTitleColor(UIColor.blue, for: .normal)
        googleMapsButton.frame = CGRect.init(x: mapViewWidth - 80, y: mapViewHeight - 70, width: 50, height: 50)
        googleMapsButton.addTarget(self, action: #selector(self.markerClick(sender:)), for: .touchUpInside)
        googleMapsButton.gps = String(marker.position.latitude) + "," + String(marker.position.longitude)
        googleMapsButton.title = marker.title
        googleMapsButton.tag = 0

        let directionsButton = CustomButton()
        directionsButton.setTitle("", for: .normal)
        directionsButton.setImage(UIImage(named: "googlemapsdirection")?.resizableImage(withCapInsets: UIEdgeInsets.init(top: 0, left: 0, bottom: 50, right: 50)),for: .normal)
        directionsButton.setTitleColor(UIColor.blue, for: .normal)
        directionsButton.frame = CGRect.init(x:mapViewWidth - 110, y:mapViewHeight - 70, width:50, height: 50)
        directionsButton.addTarget(self, action: #selector(self.markerClick(sender:)), for: .touchUpInside)
        directionsButton.gps = String(marker.position.latitude) + "," + String(marker.position.longitude)
        directionsButton.title = marker.title
        directionsButton.tag = 1
        self.view.addSubview(googleMapsButton)
        self.view.addSubview(directionsButton)
    }

    return false
}

func markerClick(sender:CustomButton){
    let fullGPS = sender.gps
    let fullGPSArr = fullGPS!.characters.split{$0 == ","}.map(String.init)

    let lat1 : String = fullGPSArr[0]
    let lng1 : String = fullGPSArr[1]


    guard let lat1_double = Double(lat1),let lng1_double = Double(lng1) else{
        return
    }

    let latitude:CLLocationDegrees =  lat1_double
    let longitude:CLLocationDegrees =  lng1_double

    if (UIApplication.shared.openURL(URL(string:"comgooglemaps://")!)) {
        if (sender.tag == 1) {
            UIApplication.shared.openURL(URL(string:
                "comgooglemaps://?saddr=&daddr=\(latitude),\(longitude)&directionsmode=driving")!)
        } else if (sender.tag == 0) {
            UIApplication.shared.openURL(URL(string:
                "comgooglemaps://?center=\(latitude),\(longitude)&zoom=14&views=traffic")!)
        }

    } else {
        let regionDistance:CLLocationDistance = 10000
        let coordinates = CLLocationCoordinate2DMake(latitude, longitude)
        let regionSpan = MKCoordinateRegionMakeWithDistance(coordinates, regionDistance, regionDistance)
        var options : NSDictionary! = nil
        if (sender.tag == 1) {
            options = [

                MKLaunchOptionsMapCenterKey: NSValue.init(mkCoordinate: regionSpan.center),
                MKLaunchOptionsMapSpanKey: NSValue(mkCoordinateSpan: regionSpan.span),
                MKLaunchOptionsDirectionsModeKey: MKLaunchOptionsDirectionsModeDriving
            ]
        } else if (sender.tag == 0) {
            options = [
                MKLaunchOptionsMapCenterKey: NSValue(mkCoordinate: regionSpan.center),
                MKLaunchOptionsMapSpanKey: NSValue(mkCoordinateSpan: regionSpan.span)
            ]
        }

        let placemark = MKPlacemark(coordinate: coordinates, addressDictionary: nil)
        let mapItem = MKMapItem(placemark: placemark)
        mapItem.name = sender.title
        mapItem.openInMaps(launchOptions: options as? [String : Any])
    }
}

I was having the same issue but in Objective-c and by following your code i've implemented. For those who wants to add the direction icon using Google Maps after tapping the Marker icon, the code below worked for me:

-(bool)mapView:(GMSMapView *)mapView didTapMarker:(GMSMarker *)marker{

    UIButton *directionsButton = [[UIButton alloc] init];
    [directionsButton setTitle:@"" forState:UIControlStateNormal];
    [directionsButton setImage:[UIImage imageNamed:@"ic_google_direction"] forState:UIControlStateNormal];
    [directionsButton setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];
    [directionsButton setFrame:CGRectMake(self->mapView.frame.size.width - 110, self->mapView.frame.size.height - 130, 50, 50)];
    [directionsButton addTarget:self action:@selector(markerClick) forControlEvents:UIControlEventTouchUpInside];
    [directionsButton setTag:1];
    [[self view] addSubview:directionsButton];

    return NO;
}

-(void) markerClick{

    NSMutableArray *installedNavigationApps = [[NSMutableArray alloc] initWithObjects:@"Apple Maps", nil];

    if ([[UIApplication sharedApplication] canOpenURL:
         [NSURL URLWithString:@"comgooglemaps://"]]) {
        [installedNavigationApps addObject:@"Google Maps"];
    }

    UIAlertController *actionSheet = [UIAlertController alertControllerWithTitle:@"Selecione um aplicativo" message:@"Abrir com" preferredStyle:UIAlertControllerStyleActionSheet];


    for (NSString *app in installedNavigationApps) {

        if([app isEqualToString:@"Apple Maps"]){

            [actionSheet addAction:[UIAlertAction actionWithTitle:app style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {

                [[UIApplication sharedApplication] openURL:
                 [NSURL URLWithString: [NSString stringWithFormat:@"http://maps.apple.com/?saddr=%@,%@&daddr=%@,%@", _latitude, _longitude, _denuncia.Latitude, _denuncia.Longitude]]];
            }]];

        }
        else if([app isEqualToString:@"Google Maps"]){
            [actionSheet addAction:[UIAlertAction actionWithTitle:app style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {

                [[UIApplication sharedApplication] openURL:
                 [NSURL URLWithString: [NSString stringWithFormat:@"comgooglemaps://?saddr=%@,%@&daddr=%@,%@&zoom=14&directionsmode=driving", _latitude, _longitude, _denuncia.Latitude, _denuncia.Longitude]]];
            }]];
        }


    }
    [actionSheet addAction:[UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:nil]];

    // Present action sheet.
    [self presentViewController:actionSheet animated:YES completion:nil];
}

CustomButton - swift just simply add the class on your viewcontroller bottom

class CustomButton: UIButton {
    var gps = ""
    override func awakeFromNib() {
        super.awakeFromNib()

        //TODO: Code for our button
    }
}

for request "appleMap" required to import MapKit