ipad - MKMapView 没有调用委托方法

Question

我正在尝试在地图上放置图钉，但它没有调用委托方法

• (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id)annotation{

我的应用程序是通用的，所以当我使用 iPhone 时，它​​会正确调用委托方法，但是当我使用 iPad 时，不会调用委托方法。代码如下：

• (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id)annotation{

  静态 NSString *identifier = @"MachineLocation";
  if ([annotation isKindOfClass:[MachineLocation class]]) {

  MKPinAnnotationView *annotationView = (MKPinAnnotationView *) [self.mapView dequeueReusableAnnotationViewWithIdentifier:identifier];
  if (annotationView == nil) {
      annotationView = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:identifier];
  } else {
      annotationView.annotation = annotation;
  }
  
  annotationView.enabled = YES;
  annotationView.canShowCallout = YES; //        
  if (isWeatherOn) {
      if (imageFlag == 0) {
          annotationView.image=[UIImage imageNamed:@"Clouds.png"];
      }
      if (imageFlag == 1) {
          annotationView.image=[UIImage imageNamed:@"Sun + Clouds.png"];
      }
      if (imageFlag == 2) {
          annotationView.image=[UIImage imageNamed:@"Sun.png"];
      }
      imageFlag++;
  }
  else
  {
      annotationView.image=[UIImage imageNamed:@"arrest.png"];
      NSLog(@"annotation");
  }
  
  annotationView.rightCalloutAccessoryView = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
  
  return annotationView;
  

  }

  返回零；}

viewWillApear 下的代码是这个

NSString *tempString;
            for(NSMutableArray *array in appDelegate.globalVehicleInfoArray) { 
                for (VehicleInfo *vehicleInfo in array) {
                    for (WeatherCondition *weather in appDelegate.globalWeatherConditionArray) {
                        if ([weather.weatherID isEqualToString:[vehicleInfo vehicleID]]) {
                            tempString = [weather weatherTempC];
                            //                            NSLog(@"weather id matched");
                        }
                    }
                    NSString *name = [vehicleInfo vehicleName];
                    NSString *machineDescription = [NSString stringWithFormat:@"%@     %@ C", [vehicleInfo vehicleLastUpdate], tempString];
                    MKPointAnnotation *annotation = [[MKPointAnnotation alloc] init];
                    CLLocationCoordinate2D coordinate;
                    coordinate.latitude = [[vehicleInfo vehicleLastPositionY] doubleValue]; 
                    coordinate.longitude = [[vehicleInfo vehicleLastPositionX] doubleValue];
                    NSLog(@"%f , %f", coordinate.latitude, coordinate.longitude);
                    MachineLocation *location = [[MachineLocation alloc] initWithId:[vehicleInfo vehicleID] :name description:machineDescription coordinate:coordinate];
//                    annotation.coordinate = coordinate;
                    [self.mapView addAnnotation:location];
                }


            }