在iphone aap地图上的多个pin drop

Question

我正在为Mapview上的多个pin drop做这个代码。

- (void)geocode
{
    NSArray *arrCityName = [NSArray arrayWithObjects:@"Baroda", @"Surat", @"Ahmedabad", @"Rajkot", @"Junagadh", @"Mumbai", @"Mehsana", @"Veraval", @"Surendranagar", @"Gondal", nil];
    CLLocationCoordinate2D coordinate;
    MKCoordinateRegion region;
    DisplayMap *ann = [[DisplayMap alloc] init];
    [_mapView setMapType:MKMapTypeStandard];
    [_mapView setZoomEnabled:YES];
    [_mapView setScrollEnabled:YES];
    [_mapView setDelegate:self];
    for (int i = 0; i < [arrCityName count]; i++)
    {
        coordinate = [self geoCodeUsingAddress:[arrCityName objectAtIndex:i]];
        NSLog(@"Lat: %f --- Long: %f --- for city:--> %@",coordinate.latitude,coordinate.longitude,[arrCityName objectAtIndex:i]);
        region.center.latitude = latitude;
        region.center.longitude = longitude;
        region.span.longitudeDelta = 1.8;
        region.span.latitudeDelta = 1.8;
        [_mapView setRegion:region animated:YES];
        ann.title = [arrCityName objectAtIndex:i];
        ann.coordinate = region.center;
        [_mapView addAnnotation:ann];
    }
}
- (CLLocationCoordinate2D) geoCodeUsingAddress:(NSString *)address
{
    latitude = 0, longitude = 0;
    NSString *esc_addr =  [address stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSString *req = [NSString stringWithFormat:@"http://maps.google.com/maps/api/geocode/json?sensor=false&address=%@", esc_addr];
    NSString *result = [NSString stringWithContentsOfURL:[NSURL URLWithString:req] encoding:NSUTF8StringEncoding error:NULL];
    if (result) {
        NSScanner *scanner = [NSScanner scannerWithString:result];
        if ([scanner scanUpToString:@""lat" :" intoString:nil] && [scanner scanString:@""lat" :" intoString:nil]) {
            [scanner scanDouble:&latitude];
            if ([scanner scanUpToString:@""lng" :" intoString:nil] && [scanner scanString:@""lng" :" intoString:nil]) {
                [scanner scanDouble:&longitude];
            }
        }
    }
    CLLocationCoordinate2D center;
    center.latitude = latitude;
    center.longitude = longitude;
    return center;
}

这里的问题只是它只给出最后一个针滴。

Answer 1

感谢@ScarletWitch的回答....通过这样的改变，我的问题得到了解决。

- (void)geocode
{    
    NSArray *arrCityName = [NSArray arrayWithObjects:@"Baroda", @"Surat", @"Ahmedabad", @"Rajkot", @"Junagadh", @"Mumbai", @"Mehsana", @"Veraval", @"Surendranagar", @"Gondal", nil];
    CLLocationCoordinate2D coordinate;
    MKCoordinateRegion region;
    [_mapView setMapType:MKMapTypeStandard];
    [_mapView setZoomEnabled:YES];
    [_mapView setScrollEnabled:YES];
    [_mapView setDelegate:self];
    NSMutableArray *arrPins = [[NSMutableArray alloc]init];
    for (int i = 0; i < [arrCityName count]; i++)
    {
        coordinate = [self geoCodeUsingAddress:[arrCityName objectAtIndex:i]];
        NSLog(@"Lat: %f --- Long: %f --- for city:--> %@",coordinate.latitude,coordinate.longitude,[arrCityName objectAtIndex:i]);
        region.center.latitude = latitude;
        region.center.longitude = longitude;
        region.span.longitudeDelta = 1.8;
        region.span.latitudeDelta = 1.8;
        [_mapView setRegion:region animated:YES];
        DisplayMap *ann = [[DisplayMap alloc] init];
        ann.title = [arrCityName objectAtIndex:i];
        ann.subtitle = @"city";
        ann.imageCity = [UIImage imageNamed:@"[e-mail]"];
        ann.coordinate = region.center;
        [arrPins addObject:ann];
        [_mapView addAnnotations:arrPins];
    }
}

Answer 2

在您的代码中，您只在"for"之外分配一次DisplayMap (Annotation)
循环，这就是它保存最后一个值而不是添加多个
的原因注释。通过在循环中分配实例来纠正代码。你也不需要一次又一次地设置mkcoordinaterregion。你可以设置一次它包含所有要显示给MapView的注释。

    -(void)geocode
    {
       NSArray *arrCityName = [NSArray arrayWithObjects:@"Baroda", @"Surat", @"Ahmedabad",   
                               @"Rajkot", @"Junagadh", @"Mumbai", @"Mehsana", @"Veraval", 
                               @"Surendranagar", @"Gondal", nil];
       CLLocationCoordinate2D coordinate;
       MKCoordinateRegion region;
       [_mapView setMapType:MKMapTypeStandard];
       [_mapView setZoomEnabled:YES];
       [_mapView setScrollEnabled:YES];
       [_mapView setDelegate:self];
       region.center.latitude = latitude;
       region.center.longitude = longitude;
       region.span.longitudeDelta = 1.8;
       region.span.latitudeDelta = 1.8;
       [_mapView setRegion:region animated:YES];
       for (int i =0 ; i<[arrCityName count] ; i++)
           {
                DisplayMap *ann = [[DisplayMap alloc] init];
                coordinate = [self geoCodeUsingAddress:[arrCityName objectAtIndex:i]];
                ann.title = [arrCityName objectAtIndex:i];
                ann.coordinate = region.center;
                [_mapView addAnnotation:ann];
            }
      }

Answer 3

当我尝试添加多个引脚时，我面临着类似的问题。我所做的是:设置一个全局计数器，在添加的每个注释上增加1，即在addannotation上。创建for循环的另一个函数:

coordinate = [self geoCodeUsingAddress:[arrCityName objectAtIndex:i]];
    NSLog(@"Lat: %f --- Long: %f --- for city:--> %@",coordinate.latitude,coordinate.longitude,[arrCityName objectAtIndex:i]);
    region.center.latitude = latitude;
    region.center.longitude = longitude;
    region.span.longitudeDelta = 1.8;
    region.span.latitudeDelta = 1.8;
    [_mapView setRegion:region animated:YES];
    ann.title = [arrCityName objectAtIndex:i];
    ann.coordinate = region.center;
    [_mapView addAnnotation:ann];

并调用该函数，直到计数达到arrCityName的计数

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation
{
static NSString *identifier = @"CarLocation";
if ([annotation isKindOfClass:[MapViewAnnotation class]]) {

    static NSString *AnnotationIdentifier = @"AnnotationIdentifier";
    MKPinAnnotationView *pinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:AnnotationIdentifier];
    if (!pinView)
    {
        pinView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:AnnotationIdentifier] autorelease];
        pinView.canShowCallout = YES;
        pinView.animatesDrop = YES;
    }
    else
    {
        pinView.annotation = annotation;
    }
    UIImageView *leftCalloutView = [[UIImageView alloc]
                                    initWithImage:((MapViewAnnotation *)annotation).imagePin];
    pinView.leftCalloutAccessoryView = leftCalloutView;
    pinView.image = leftCalloutView.image;
    [leftCalloutView release];
    [self performSelector:@selector(intermediate) withObject:nil afterDelay:1.05];

    return pinView;
}