Ios 标注附件未出现

我正在尝试将常规详图索引附件添加到注释区域，但由于某些原因，它没有显示出来。 代码如下：

- (void) setupMap:(PFObject*) venue {

...

OTNVenueAnnotation *annotation = [[OTNVenueAnnotation alloc] init];
annotation.coordinate = CLLocationCoordinate2DMake(location.latitude, location.longitude);
annotation.title = [[venue objectForKey:@"name"] uppercaseString];
annotation.venue = venue;


UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];

MKPinAnnotationView *customPinView = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"identifier"];
customPinView.leftCalloutAccessoryView = rightButton;
[self.mapView addAnnotation: annotation];

}

---

尝试在地图视图视图的委托方法中为注释设置leftCalloutAccessoryView，例如：

- (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>) annotation 
{
    MKPinAnnotationView *annView= (MKPinAnnotationView *)[self.mapView dequeueReusableAnnotationViewWithIdentifier:@"identifier"];
    UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
    annView.leftCalloutAccessoryView = rightButton;
    annView.canShowCallout = YES;
    return annView;
}

-（MKAnnotationView*）地图视图：（MKMapView*）地图视图注释：（id）注释
{
MKPinAnnotationView*annView=（MKPinAnnotationView*）[self.mapView dequeuereusableannotationview with identifier:@“identifier”]；
UIButton*rightButton=[UIButton Button类型：UIButtonTypedTailButton]；
annView.leftCalloutAccessoryView=rightButton；
annView.canShowCallout=是；
返回视图；
}