title: Google map is showing white screen in iOS when run second time?
body: <p>I am displaying the google map using Google Maps SDK for iOS. When I start the view controller first time it shows the map fine. But when I goto the view controller second time it does not display the google map. It shows the blank screen. Actually I am passing the address in the google geo coding api from there I am getting the <code>lang &amp; lat</code> then I am displaying the google map.</p>
  
  <p><strong>Code for displaying google map</strong></p>
  
  <pre><code>//
  //  GmapViewController.m
  //  MyDex
  //  Created by Admin on 8/18/15.
  //  Copyright (c) 2015 com.vastedge. All rights reserved.
  #import "GmapViewController.h"
  #import "AFNetworking.h"
  #import "UIKit+AFNetworking.h"
  @import GoogleMaps;
  @interface GmapViewController ()
  
  @end
  
  @implementation GmapViewController
  {
      GMSMapView *mapView_;
      NSString *lat;
      NSString *lng;
      CLLocationDegrees latitude;
      CLLocationDegrees longitude;
      UIActivityIndicatorView *activityView;
  }
  
  -(void)geoCodeAddress
  {
      NSCharacterSet *doNotWant = [NSCharacterSet characterSetWithCharactersInString:@":/,."];
      self.address = [[self.address componentsSeparatedByCharactersInSet: doNotWant] componentsJoinedByString: @""];
      NSString *urlString=[NSString stringWithFormat:@"https://maps.googleapis.com/maps/api/geocode/json?address=%@",self.address];
  
      urlString = [urlString stringByAddingPercentEscapesUsingEncoding:
                   NSUTF8StringEncoding];
      AFHTTPRequestOperationManager *manager = [[AFHTTPRequestOperationManager alloc] initWithBaseURL:[NSURL URLWithString:urlString]];
      manager.requestSerializer = [AFJSONRequestSerializer serializer];
      AFHTTPRequestOperation *operation = [manager GET:urlString parameters:nil
                                               success:^(AFHTTPRequestOperation *operation, id responseObject)
                          {
                            NSArray * results = [responseObject objectForKey:@"results"];
                            NSDictionary *records=[results objectAtIndex:0];
                            NSDictionary *geometry=[records objectForKey:@"geometry"];
                            NSLog(@"geomatry is %@",geometry);
                            NSDictionary *latLong=[geometry objectForKey:@"location"];
                            lat=[latLong objectForKey:@"lat"];
                            lng=[latLong objectForKey:@"lng"];
                            latitude=[lat floatValue];
                            longitude=[lng floatValue];
                             NSLog(@"main lat is %f",latitude);
                             NSLog(@"main lng is %f",longitude);
                            [self activityIndicator:@"hide"];
                            [self Loadgmap];
                          }
              failure:^(AFHTTPRequestOperation *operation, NSError *error)
                  {
                      NSLog(@"failure string is");
                       [self activityIndicator:@"hide"];
                      UIAlertView *alert =[[UIAlertView alloc]initWithTitle:@"Warning" message:@"Unable to display map" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil];
                      [alert show];
                  }];
      [operation start];
  }
  - (void)viewDidLoad
  {
      [super viewDidLoad];
      [self activityIndicator:@"show"];
      [self geoCodeAddress];
  }
  -(void)Loadgmap
  {
      GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:-33.868
                                                              longitude:151.2086
                                                                   zoom:6];
      GMSMapView *mapView = [GMSMapView mapWithFrame:CGRectZero camera:camera];
      GMSMarker *marker = [[GMSMarker alloc] init];
      marker.position = camera.target;
      marker.snippet = @"Hello World";
      marker.appearAnimation = kGMSMarkerAnimationPop;
      marker.map = mapView;
  
      self.view = mapView;
  }
  
  -(void)activityIndicator:(NSString *)show
  {
          if([show isEqual:@"show"])
          {
              NSLog(@"loading shown");
  
              [[UIApplication sharedApplication] beginIgnoringInteractionEvents];
              activityView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
              activityView.layer.backgroundColor = [[UIColor colorWithWhite:0.0f alpha:0.5f] CGColor];
              activityView.hidesWhenStopped = YES;
              activityView.frame = self.view.bounds;
              [self.view addSubview:activityView];
              [activityView startAnimating];
          }
          else
          {
              [[UIApplication sharedApplication] endIgnoringInteractionEvents];
              [activityView stopAnimating];
              [activityView removeFromSuperview];
          }
      }
  
    - (void)didReceiveMemoryWarning
  {
      [super didReceiveMemoryWarning];
      // Dispose of any resources that can be recreated.
  }
  
  /*
  #pragma mark - Navigation
  
  // In a storyboard-based application, you will often want to do a little preparation before navigation
  - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
      // Get the new view controller using [segue destinationViewController].
      // Pass the selected object to the new view controller.
  }
  */
  
  @end
  </code></pre>