How to add a button on the Google maps in iOS?

Question

I am new to iOS Programming and I have downloaded the google maps sdk for iOS and followed the instruction on their website ( as shown in this link https://developers.google.com/maps/documentation/ios/start ) and was able to get the map in my application.

Now I am trying to add a button on the screen at the bottom over Google maps for giving an option to the user to go back to the previous screen.

I just know that UIButton is a subclass of UIView and we can make a button appear on a view by making it the sub view of that class. Previously iOS used to use Google Maps by default by MKMapView and I have seen examples in books an on the Internet showing screen shots of apps where a button or a text box would appear on the map. But now just dragging the button in the interface builder doesn't help with the SDK of google maps.

Here is my code:

ViewController.h

#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
#import <GoogleMaps/GoogleMaps.h>


@interface ViewController : UIViewController 

@property (weak, nonatomic) IBOutlet UIButton *btn;


@end

ViewController.m

#import "ViewController.h"
#import <MapKit/MapKit.h>
#import <GoogleMaps/GoogleMaps.h>
#import <CoreLocation/CoreLocation.h>


@interface ViewController ()

@end

@implementation ViewController
{
    GMSMapView *mapView_;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)loadView
{
    CLLocationManager *locationManager = [[CLLocationManager alloc] init];
    locationManager.distanceFilter = kCLDistanceFilterNone;

    locationManager.desiredAccuracy = kCLLocationAccuracyKilometer;
    [locationManager startUpdatingLocation];

    //Latitude and longitude of the current location of the device.
    double lati = locationManager.location.coordinate.latitude;
    double longi = locationManager.location.coordinate.longitude;
    NSLog(@"Latitude = %f", lati);
    NSLog(@"Longitude = %f", longi);

    CLLocation *myLocation = [[CLLocation alloc] initWithLatitude:lati longitude:longi];

    // Create a GMSCameraPosition that tells the map to display the coordinate

    GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:lati
                                                            longitude:longi
                                                                 zoom:11.5];

    mapView_ = [GMSMapView mapWithFrame:[[UIScreen mainScreen] bounds] camera:camera];
    mapView_.myLocationEnabled = YES;
    self.view = mapView_;

    // Creates a marker in the center of the map.
    GMSMarker *marker = [[GMSMarker alloc] init];
    marker.position = CLLocationCoordinate2DMake(lati, longi);
    marker.title = @"It's Me";
    marker.snippet = @"My Location";
    marker.map = mapView_;

    [mapView_ addSubview:_btn];
    [mapView_ bringSubviewToFront:_btn];

}
@end

You can see that in the last 2 lines I have made the button the subview of mapview and tried to bring it front. But this didn't help. Please let me know what is it that I am missing or if there is another way to do this by using some other function.

Please also do check the screenshot of the storyboard which I have created so that you can understand better what I am trying to do here.

Thanks.

Answer 1

This problem occur because you try to add the map view with the code, earlier you add the button with the help of interface builder. When you add the mapView it would add at the top of the view that's why your button is not shown.

You have two options for doing this.

First approach

• Drag and drop the UIButton from the interface builder and set the constraints accordingly

• Then create the outlet of that button in the corresponding viewController

  @IBOutlet weak var bottonToAdd: UIButton!

• After adding the map view to the view paste the blow code to bring the button at the top mapViewForScreen.addSubview(self.bottonToAdd) mapViewForScreen.bringSubviewToFront(self.bottonToAdd)

After the above three step you can find out that you hav the button over mapview

Second approach

If you don't want to use the interface builder you can use the below code for the same.

    var bottonToAdd:UIButton = UIButton()
    bottonToAdd.setTitle("Button To Add", for: .normal)
    bottonToAdd.sizeToFit()
    bottonToAdd.center = mapViewForScreen.center
    bottonToAdd.tintColor = UIColor.blue
    mapViewForScreen.addSubview(bottonToAdd)
    mapViewForScreen.bringSubviewToFront(bottonToAdd)

Answer 2

GMSMapView is subclass of UIView so you can add subviews as to any other view

Try this code

UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
button.frame = CGRectMake(mapView_.bounds.size.width - 110, mapView_.bounds.size.height - 30, 100, 20);
button.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleTopMargin;
[button setTitle:@"Button" forState:UIControlStateNormal];
[mapView_ addSubview:button];

It adds 100x20 button as the subview of the GMSMapView, positioned to the bottom right corner. I have tested it and the button can be touched as in any other view

Edit: Also move all your code from -loadView to -viewDidLoad. -loadView method is never called when using IB to create UI. Docs to -loadView says:

If you use Interface Builder to create your views and initialize the view controller, you must not override this method.

Edit 2: I believe when you create view hierarchy using Interface Builder, you CAN NOT reset self.view property like you are doing.

Do this in your -viewDidLoad

[self.view addSubview: mapView_];

instead of

self.view = mapView_;

if you are passing GMSMapView to the self.view property, the map is only view which is in the controller from this point. Thats, I believe, the reason why u can't see your IB-created button.