MKAnnotationView 无法正常工作

Question

我正在尝试根据对象值替换 MKAnnotationView 图像，代码已执行但图像是随机分配的，因此它们与正确的值不匹配。

- (MKAnnotationView *)mapView:(MKMapView *)mapview viewForAnnotation:(EventAnnotation *)annotation{

if ([annotation isKindOfClass:[MKUserLocation class]])
    return nil;
static NSString* AnnotationIdentifier = @"AnnotationIdentifier";
MKAnnotationView *annotationView = [mapview dequeueReusableAnnotationViewWithIdentifier:AnnotationIdentifier];

if(annotationView)
    return annotationView;
else
{
    MKAnnotationView *annotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation
                                                                    reuseIdentifier:AnnotationIdentifier];
    annotationView.canShowCallout = YES;
    annotationView.image = [self setImageByType:annotation];
    annotationView.draggable = NO;

    return annotationView;
}
return nil;
}

setImageByType 方法：

- (UIImage*)setImageByType:(EventAnnotation *)annotation{
//Set annotation image depending on its type
UIImage *image = [[UIImage alloc]init];
NSString *type = annotation.type;

if ([type isEqualToString:@"event"]) {
    image = [UIImage imageNamed:@"geolocalization_events"];
}else if ([type isEqualToString:@"show"]){
    image = [UIImage imageNamed:@"geolocalization_shows"];
}else if ([type isEqualToString:@"culture"]){
    image = [UIImage imageNamed:@"geolocalization_culture"];
}else if ([type isEqualToString:@"eat"]){
    image = [UIImage imageNamed:@"geolocalization_eat"];
}else if ([type isEqualToString:@"drink"]){
    image = [UIImage imageNamed:@"geolocalization_drink"];
}else if ([type isEqualToString:@"cybercafe"]){
    image = [UIImage imageNamed:@"geolocalization_cybercafe"];
}

UIImage *finalImage = [self imageWithImage:image scaledToSize:CGSizeMake(50, 50)];

return finalImage;
}

调整图像大小：

- (UIImage *)imageWithImage:(UIImage *)image scaledToSize:(CGSize)newSize {
//Resize annotation image
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
[image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

return newImage;
}

我会说代码的执行速度比图像分配给视图的速度快。有什么想法吗？

Answer 1

选项 1

尝试更改此行：

static NSString* AnnotationIdentifier = @"AnnotationIdentifier";

为此：

NSString* AnnotationIdentifier = annotation.type;

选项 2:

这一行之后：

MKAnnotationView *annotationView = [mapview dequeueReusableAnnotationViewWithIdentifier:AnnotationIdentifier];

添加这一行：

annotationView.image = [self setImageByType:annotation];

MKAnnotationView 无法正常工作

MKAnnotationView not working properly

ios

objective-c

mapkit

mkannotation

mkannotationview