我的GMSMarker显示在左上方，我想在中心物镜上显示它-c

如何解决我的GMSMarker显示在左上方，我想在中心物镜上显示它-c

我想在地图中心显示我的标记，但它显示在左上方。

下面是我的代码实现：

- (void)viewDidLoad {
    [super viewDidLoad];
NSDictionary *userLoc=[kNSUserDefaults objectForKey:@"userLocation"];
mapView_.delegate = self;
CGFloat lat = [[userLoc objectForKey:@"lat"] floatValue];
CGFloat lon = [[userLoc objectForKey:@"long"] floatValue];
   
GMSMarker *marker = [[GMSMarker alloc] init];
    
marker.position = CLLocationCoordinate2DMake(lat,lon);
mapView_.myLocationEnabled = YES;
mapView_.settings.myLocationButton = YES;
mapView_.mapType = kGMSTypeHybrid;
marker.map = mapView_;
GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:lat longitude:lon zoom:17];
[mapView_ animatetoCameraPosition:camera];
[mapView_ setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight];
mapView_.settings.compassButton = YES;
mapView_.mapType = kGMSTypeHybrid;
mapView_.settings.myLocationButton = YES;
mapView_.delegate = self;
mapView_.trafficEnabled = YES;
}

无法理解我的代码出了什么问题。

谢谢！