自定义注释不显示标注

Question

我在自定义MKAnnotaionView中得到奇怪的东西。当我点击它时它没有显示它的细节。我犯了什么错吗？

这是我的代码：

- (MKAnnotationView *) mapView:(MKMapView *)mapView1 viewForAnnotation:(id 
<MKAnnotation>) annotation
{
 MKPinAnnotationView *annotationView = [[MKPinAnnotationView alloc]   
initWithAnnotation:annotation reuseIdentifier:@"redpin"];
annotationView.pinColor = MKPinAnnotationColorRed;
annotationView.animatesDrop = YES;

UIButton *button = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
button.frame = CGRectMake(0, 0, 23, 23);
annotationView.rightCalloutAccessoryView = button;

// Image and two labels
UIView *leftCAV = [[UIView alloc] initWithFrame:CGRectMake(0,0,23,23)];
UILabel *label1 = [[UILabel alloc]init];
label1.text = [NSString stringWithFormat:@"hello"]; 

[leftCAV addSubview :label1];
 annotationView.leftCalloutAccessoryView = leftCAV;

annotationView.canShowCallout = YES;

return annotationView;
}