在地图视图中显示动态注释图钉

Question

我正在开发一个使用MKMapView 的应用程序。我在其中显示了多个注释。现在我想为 pin 显示自定义注释图像。 我已经为 MapViewAnnotation 制作了自定义类。

#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>

@interface MapViewAnnotation : NSObject <MKAnnotation>

@property (nonatomic,copy) NSString *title;
@property (nonatomic,copy) NSString *subtitle;
@property (nonatomic, readonly) CLLocationCoordinate2D coordinate;

-(id) initWithTitle:(NSString *) title SubTitle:(NSString *)subtitle AndCoordinate:(CLLocationCoordinate2D)coordinate;

@end

---

#import "MapViewAnnotation.h"

@implementation MapViewAnnotation

@synthesize coordinate=_coordinate;
@synthesize title=_title;

-(id) initWithTitle:(NSString *) title SubTitle:(NSString *)subtitle AndCoordinate:(CLLocationCoordinate2D)coordinate;
{
    self =  [super init];
    _title = title;
    _coordinate = coordinate;
    _subtitle = subtitle;
    return self;
}

@end

我从 api 获取多个 lat-long 并以这种方式显示：

[self.map_parking addAnnotations:[self createAnnotations]];

---

- (NSMutableArray *)createAnnotations
{
    NSMutableArray *annotations = [[NSMutableArray alloc] init];

    for (NSDictionary *row in arrfinal) {
        NSNumber *latitude = [row objectForKey:@"latitude"];
        NSNumber *longitude = [row objectForKey:@"longitude"];
        NSString *title = [row objectForKey:@"title"];
        NSString *subtitle = [row objectForKey:@"subtitle"];
        NSString *rate = [row objectForKey:@"rate"];

        //Create coordinates from the latitude and longitude values
        CLLocationCoordinate2D coord;
        coord.latitude = latitude.doubleValue;
        coord.longitude = longitude.doubleValue;

        MapViewAnnotation *annotation = [[MapViewAnnotation alloc] initWithTitle:title SubTitle:subtitle AndCoordinate:coord];

        MKAnnotationView *av = [map_parking viewForAnnotation:annotation];
        if ([rate isEqualToString:@"0.00"])
        {
            av.image = [UIImage imageNamed:@"marker2"];
        }
        else
        {
            av.image = [UIImage imageNamed:@"marker"];
        }
        [annotations addObject:annotation];

    }
    return annotations;
}

要显示注释，我正在使用此链接引用的此方法：MKMapView: Instead of Annotation Pin, a custom view

-(MKAnnotationView *)mapView:(MKMapView *)mV viewForAnnotation:(id <MKAnnotation>)annotation
{
    MKAnnotationView *pinView = nil;
    if(annotation != map_parking.userLocation)
    {
        static NSString *defaultPinID = @"com.invasivecode.pin";
        pinView = (MKAnnotationView *)[map_parking dequeueReusableAnnotationViewWithIdentifier:defaultPinID];
        if ( pinView == nil )
            pinView = [[MKAnnotationView alloc]
                       initWithAnnotation:annotation reuseIdentifier:defaultPinID];

        pinView.canShowCallout = YES;
        //pinView.animatesDrop = YES;
        for (int i=0; i<arrrates.count; i++)
        {
            if ([[arrrates objectAtIndex:i] isEqualToString:@"0.00"])
            {
                pinView.image = [UIImage imageNamed:@"marker1"];
            }
            else if ([[arrrates objectAtIndex:i] isEqualToString:@"100.71"])
            {
                pinView.image = [UIImage imageNamed:@"marker2"];
            }
            else
            {
                pinView.image = [UIImage imageNamed:@"marker3"];
            }
        }

    }
    else {
        [map_parking.userLocation setTitle:@"I am here"];
    }

    return pinView;
}

在此方法中if-else 条件工作良好，但所有 pin 图像显示这是最后一个条件。

Answer 1

让你退出循环

if ( pinView == nil )

如果块假设只制作可重复使用的注释引脚，并且如果引脚对象已经存在，则只会运行一次。