iphone mkannotation：地图加载后左侧标注发出警告

Question

我有一个 MKMapview 加载，可能有 5 个注释（现在）。它加载得很好，也带有注释。每个注释都包含正确的左右标注。然而，过了一会儿（也许 2 分钟），我经常会在注释的左侧标注上遇到 EXC_BAD_ACCESS 崩溃...

- (MKAnnotationView *) mapView:(MKMapView *)thisMapView 
         viewForAnnotation:(MapAnnotations *)annotation
{
static NSString *MapIdentifier = @"MapIdentifier";

UIImageView *myImageView;
MKPinAnnotationView *annotationView = (MKPinAnnotationView *)[thisMapView dequeueReusableAnnotationViewWithIdentifier:MapIdentifier];

if(annotationView == nil)
{   
    NSString * id = [NSString stringWithFormat:@"%d", (annotation).tag];
    NSString * postPhoto = [NSString stringWithFormat:@"id=%@",id];
    NSString * hostStrPhoto = @"http://domain.com/get_image.php?";
    hostStrPhoto = [hostStrPhoto stringByAppendingString:postPhoto];

    NSData *imgData = [NSData dataWithContentsOfURL:[NSURL URLWithString:hostStrPhoto]];

    myImageView = [[UIImageView alloc] initWithImage:[UIImage imageWithData: imgData]];

    myImageView.frame = CGRectMake(0,0,31,31); 

    annotationView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:MapIdentifier] autorelease];

}

annotationView.animatesDrop=TRUE;


annotationView.canShowCallout = YES;
annotationView.leftCalloutAccessoryView = myImageView; //<--where I am getting the error, after all the annotations have loaded.
annotationView.rightCalloutAccessoryView = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];

return annotationView;

[myImageView autorelease]; 

}

我想也许我的应用程序仍在尝试加载注释，但我不明白为什么。另外，加载地图时我会收到一些内存警告，所以也许我没有按照应有的方式释放一些对象，我对内存管理的工作方式仍然很陌生，所以任何建议都会有所帮助。

Answer 1

如果您最终重新使用注释视图，则不会创建 myImageView，但您将释放它。在顶部将 myImageView 设置为 nil。

- (MKAnnotationView *) mapView:(MKMapView *)thisMapView viewForAnnotation:(MapAnnotations *)annotation {
    static NSString *MapIdentifier = @"MapIdentifier";

    UIImageView *myImageView = nil;
    MKPinAnnotationView *annotationView = (MKPinAnnotationView *)[thisMapView dequeueReusableAnnotationViewWithIdentifier:MapIdentifier];

    if(annotationView == nil) {   
        NSString * id = [NSString stringWithFormat:@"%d", (annotation).tag];
        NSString * postPhoto = [NSString stringWithFormat:@"id=%@",id];
        NSString * hostStrPhoto = @"http://domain.com/get_image.php?";
        hostStrPhoto = [hostStrPhoto stringByAppendingString:postPhoto];

        NSData *imgData = [NSData dataWithContentsOfURL:[NSURL URLWithString:hostStrPhoto]];

        myImageView = [[UIImageView alloc] initWithImage:[UIImage imageWithData: imgData]];

        myImageView.frame = CGRectMake(0,0,31,31); 

        annotationView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:MapIdentifier] autorelease];
    }

    annotationView.animatesDrop=TRUE;
    annotationView.canShowCallout = YES;
    annotationView.leftCalloutAccessoryView = myImageView; //<--where I am getting the     error, after all the annotations have loaded.
    annotationView.rightCalloutAccessoryView = [UIButton     buttonWithType:UIButtonTypeDetailDisclosure];

    return annotationView;

    [myImageView release]; 
}