iphone - MapKit 不显示当前位置的蓝点

Question

我是 iPhone 版 MapKit 的新手，尝试实现此功能，由于某种原因我看不到当前位置蓝点，其他人也有这个问题吗？？？

#import "DetailMapViewController.h"
#import "mapAnnotations.h"

@implementation DetailMapViewController

@synthesize inStock;

-(void)getlocation:(CLLocationCoordinate2D)loc
{
    location = loc;
}

- (void)viewDidLoad 
{
    [super viewDidLoad];
    self.navigationItem.title = @"Street View";
    mapView = [[MKMapView alloc] initWithFrame:self.view.bounds];
    mapView.delegate=self;      
    //MKCoordinateRegion region;
    MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance(location, 5000, 5000);

    mapAnnotations *ann = [[mapAnnotations alloc] init];
    ann.title = @"";
    ann.subtitle = @"";
    ann.coordinate = region.center;

    mapView.showsUserLocation = YES;
    [mapView addAnnotation:ann];
    [mapView setRegion:region animated:TRUE];
    [mapView regionThatFits:region];
    [self.view insertSubview:mapView atIndex:0];
}


- (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>) annotation
{
    MKPinAnnotationView *annView=[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"currentloc"];

    if (annotation == mapView.userLocation)
    {

        annView = [mapView dequeueReusableAnnotationViewWithIdentifier:@"blueDot"];
        if (annView != nil)
        {
            annView.annotation = annotation;
        }
        else
        {
            annView = [[[NSClassFromString(@"MKUserLocationView") alloc] initWithAnnotation:annotation reuseIdentifier:@"blueDot"] autorelease];


        }
    }

    if([inStock isEqual:@"yes"]){
        annView.pinColor = MKPinAnnotationColorGreen;
    } 
    if([inStock isEqual:@"no"]){
        annView.pinColor = MKPinAnnotationColorRed;
    }
    if([inStock isEqual:@"unknown"]){

        UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"greyPin.png"]];
        [annView addSubview:imageView];




    }
    annView.animatesDrop=TRUE;
    annView.canShowCallout = YES;
    annView.calloutOffset = CGPointMake(-5, 5);
    return annView;
}

- (void)dealloc {
    [super dealloc];
}


@end

Answer 1

按照 viewForAnnotation 当前的编写方式，当尝试显示当前位置时，它实际上应该崩溃，因为“蓝点”注释 View 没有 pinColor 或 animatesDrop 属性。

尝试将其更改为以下内容:

- (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>) annotation
{
    if ([annotation isKindOfClass:MKUserLocation.class]) {
        //user location view is being requested,
        //return nil so it uses the default which is a blue dot...
        return nil;
    }

    MKPinAnnotationView *annView=[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"currentloc"];

    if([inStock isEqual:@"yes"]){
        annView.pinColor = MKPinAnnotationColorGreen;
    } 
    if([inStock isEqual:@"no"]){
        annView.pinColor = MKPinAnnotationColorRed;
    }
    if([inStock isEqual:@"unknown"]){
        UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"greyPin.png"]];
        [annView addSubview:imageView];
    }
    annView.animatesDrop=TRUE;
    annView.canShowCallout = YES;
    annView.calloutOffset = CGPointMake(-5, 5);
    return annView;
}

在模拟器上，用户的位置将为美国加利福尼亚州库比蒂诺(旧金山以南一点)。如果您自己的注释不在 5000 米范围内，您将看不到蓝点。您必须缩小才能看到它。