信息窗口在 didTapAtCoordinate 方法中不显示标记

我想展示infowindow and marker两者同时进行。

code

-(void)set_markerOnMap:(double)lat longitude:(double)lon{

    GMSMarker *marker = [[GMSMarker alloc] init];
    marker.title = @"Location selected";
    marker.position = CLLocationCoordinate2DMake(lat, lon);
    marker.snippet = @"Testing";
    marker.icon=[UIImage imageNamed:@"red-pin.png"];
    marker.map = self.MyMapView;

    [self.MyMapView setSelectedMarker:marker];

}

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self set_markerOnMap:21.214894 longitude:72.88087];
    self.MyMapView.delegate=self;
}

上面的代码工作正常并且显示了两者infowindow and marker一起。 但我的问题是当我打电话时set_markerOnMap方法来自didTapAtCoordinate代替viewDidLoad它不起作用，只能marker显示。

code:

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.MyMapView.delegate=self;


}

- (void) mapView:       (GMSMapView *)  mapView
didTapAtCoordinate:     (CLLocationCoordinate2D)    coordinate{

 [self set_markerOnMap:21.214894 longitude:72.88087];

}

任何人都可以帮助我，我哪里错了？

看看这是否有效...

[[NSOperationQueue mainQueue] addOperationWithBlock:^{
    [self set_markerOnMap:21.214894 longitude:72.88087];
}];