iphone mkannotation：地图加载后左侧标注警告答案

【问题标题】：iphone mkannotation: warning on left callout after map has loadediphone mkannotation：地图加载后左侧标注警告
【发布时间】：2011-08-12 19:44:52
【问题描述】：

我有一个 MKMapview 加载可能有 5 个注释（现在）。它加载得很好，还有注释。每个注释都包含正确的左右标注。但是过了一段时间（可能是 2 分钟），我经常在注释的左侧标注处遇到 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];

}

我在想也许我的应用仍在尝试加载注释，但我不知道为什么。同样，在加载地图时我会收到一些内存警告，所以也许我没有按照我应该的方式释放一些对象，我对内存管理的工作方式还是有点陌生，所以任何建议都会有所帮助。

【问题讨论】：

标签： objective-c mkmapview mkannotation mkannotationview

【解决方案1】：

如果您最终重新使用注释视图，则不会创建 myImageView，但您正在释放它。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]; 
}

【讨论】：