- (MKAnnotationView *)mapView 没有被调用

Question

在我的代码中，- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation 方法没有被调用。我不知道为什么。谁能帮帮我？

下面是我的代码：

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation 
{

    MKPinAnnotationView *pinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:@","];
    NSLog(@"pin map");
    if(pinView == nil) 
    {
        pinView = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@""];

        pinView.animatesDrop = YES;
        pinView.canShowCallout = YES;

        UIImage *image = [UIImage imageNamed:@"ann.png"];

        CGRect resizeRect;

        resizeRect.size = image.size;
        CGSize maxSize = CGRectInset(self.view.bounds,
                                     [map annotationPadding],
                                     [map annotationPadding]).size;*/
        maxSize.height -= self.navigationController.navigationBar.frame.size.height + [map calloutHeight];
        if (resizeRect.size.width > maxSize.width)
            resizeRect.size = CGSizeMake(maxSize.width, resizeRect.size.height / resizeRect.size.width * maxSize.width);
        if (resizeRect.size.height > maxSize.height)
            resizeRect.size = CGSizeMake(resizeRect.size.width / resizeRect.size.height * maxSize.height, maxSize.height);

        resizeRect.origin = (CGPoint){0.0f, 0.0f};

        UIGraphicsBeginImageContext(resizeRect.size);
        [image drawInRect:resizeRect];
        UIImage *resizedImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();

        pinView.image = resizedImage;
        pinView.opaque = NO;

        UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
        [rightButton addTarget:self
                        action:@selector(showDetails:)
              forControlEvents:UIControlEventTouchUpInside];
        pinView.rightCalloutAccessoryView = rightButton;

        if (annotation == mapView.userLocation)
        {

            return nil;
        }
        return pinView;

    } 
    else 
    {

        pinView.annotation = annotation;
    }

    return pinView;

}

这就是我向地图添加注释的方式：

-(void) Annotations:(int)i
{

    /*NSString* address = [mpartyDetail objectAtIndex:i];
    address = [[address componentsSeparatedByCharactersInSet: [NSCharacterSet whitespaceCharacterSet]] componentsJoinedByString: @""];
    NSString *urlString = [NSString stringWithFormat:@"http://maps.google.com/maps/geo?q=%@&output=csv", address];
    NSLog(@"nsstring %@",urlString);
    NSString *locationString = [[[NSString alloc] initWithContentsOfURL:[NSURL URLWithString:urlString]] autorelease];
    NSLog(@"location string %@",locationString);
    NSArray *latlng = [locationString componentsSeparatedByString:@","];
    NSLog(@"the latlng %@",latlng);

    float lat = [[latlng objectAtIndex:2] floatValue];
    float lng = [[latlng objectAtIndex:3] floatValue]; */
    NSLog(@"ann");
    lat = [[latiArray objectAtIndex:i]floatValue];
    lng = [[longiArray objectAtIndex:i]floatValue]; 
    CLLocationCoordinate2D newCoord = {lat,lng};
    mapAnnotations* annotation = [[mapAnnotations alloc] initWithCoordinate:newCoord];

    [mapView addAnnotation:annotation];

}

mapAnnotations 是另一个类。下面的代码显示了被调用的那个类的方法：

- (id)initWithCoordinate:(CLLocationCoordinate2D)coordinate{

    NSLog(@"the cor");
    self = [super init];

    if (self != nil) {
        NSLog(@"in");
        _coordinate = coordinate;

    }

    return self;

}

我的想法是当用户在地图上按下时添加注释，用户可以为该图钉指定任何标题。我需要一个标注来显示用户输入的标题。正在添加注释。但我无法获得标注，因为没有调用此方法。

Answer 1

您是否将包含该方法的类指定为您的地图视图的委托，您是否确实向地图视图添加了任何注释，以及这些注释的位置是否在当前显示在屏幕上的地图部分中实际可见?

Answer 2

正如有人正确指出，在我的情况下，委托未设置为同一类 我所做的只是在我添加注释的代码中我编写了代码：

mapView.delegate=self;

它对我很有用。 如果你不这样做，那么它可能对你也有用。

Answer 3

您是如何向地图添加注释的？我使用以下

while(some condition){
MapAnnotation *annotation = [[MapAnnotation alloc] initWithLatitude:(float)goLat Longitude:(float)goLng title:(NSString*)recallTask.blurb subtitle:(NSString*)recallTask.location];
        [appDelegate.annArray addObject:annotation];
        [annotation release];
        annotation = nil;
    }
[self.mapView addAnnotations:appDelegate.annArray];