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我已经有这个问题几个星期了，我仍然没有找到答案。在我的 MapView 上，我有自定义注释，当我点击“重新加载按钮”时，所有信息都是正确的，如注释“标题，副标题”。但注释已更改。注释在 a 中NSMutableArray，我确信我遇到的问题围绕着这个问题。这是我用来重新加载注释的代码。

所以只是防止任何混淆，当我第一次加载 mapView 时，我的自定义注释工作得很好。但是一旦我点击重新加载按钮，所有注释的信息，如“位置、标题、副标题”都是正确的，只是实际的注释发生了变化。就像所有的注释都被调换了一样。如果有人可以提供帮助，将不胜感激！谢谢！

- (IBAction)refreshMap:(id)sender {
NSArray *annotationsOnMap = myMapView.annotations;
[myMapView removeAnnotations:annotationsOnMap];
[locations removeAllObjects];
[citiesArray removeAllObjects];
[self retrieveData];
}


-(void) retrieveData {
userLAT = [NSString stringWithFormat:@"%f", myMapView.userLocation.coordinate.latitude];
userLNG = [NSString stringWithFormat:@"%f", myMapView.userLocation.coordinate.longitude];

NSString *fullPath = [mainUrl stringByAppendingFormat:@"map_json.php?userID=%@&lat=%@&lng=%@",theUserID,userLAT,userLNG];

NSURL * url =[NSURL URLWithString:fullPath];
NSData *data = [NSData dataWithContentsOfURL:url];

json =[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];


citiesArray =[[NSMutableArray alloc]init];
for (int i = 0; i < json.count; i++)
{
    //create city object
    NSString * eID =[[json objectAtIndex:i] objectForKey:@"userid"];
    NSString * eAddress =[[json objectAtIndex:i] objectForKey:@"full_address"];
    NSString * eHost =[[json objectAtIndex:i] objectForKey:@"username"];
    NSString * eLat =[[json objectAtIndex:i] objectForKey:@"lat"];
    NSString * eLong =[[json objectAtIndex:i] objectForKey:@"lng"];
    NSString * eName =[[json objectAtIndex:i] objectForKey:@"Restaurant_name"];
    NSString * eState = [[json objectAtIndex:i] objectForKey:@"type"];
    NSString * annotationPic = [[json objectAtIndex:i] objectForKey:@"Annotation"];
    NSString * eventID = [[json objectAtIndex:i] objectForKey:@"id"];

    //convert lat and long from strings

    float floatLat = [eLat floatValue];
    float floatLONG = [eLong floatValue];
    City * myCity =[[City alloc] initWithRestaurantID: (NSString *) eID andRestaurantName: (NSString *) eName andRestaurantState: (NSString *) eState andRestaurantAddress: (NSString *) eAddress andRestaurantHost: eHost andRestaurantLat: (NSString *) eLat andRestaurantLong: (NSString *) eLong];
    //Add our city object to our cities array
    // Do any additional setup after loading the view.

    [citiesArray addObject:myCity];

    //Annotation

    locations =[[NSMutableArray alloc]init];
    CLLocationCoordinate2D location;
    Annotation * myAnn;

    //event1 annotation
    myAnn =[[Annotation alloc]init];
    location.latitude = floatLat;
    location.longitude = floatLONG;
    myAnn.coordinate = location;
    myAnn.title = eName;
    myAnn.subtitle = eHost;
    myAnn.type = eState;
    myAnn.AnnotationPicture = annotationPic;
    myAnn.passEventID = eventID;
    myAnn.hotZoneLevel = hotZone;
    [locations addObject:myAnn];
    [self.myMapView addAnnotations:locations];

}

}



 - (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation
{

if([annotation isKindOfClass:[MKUserLocation class]])
    return nil;

static NSString *annotationIdentifier = @"AnnotationIdentifier";

MKAnnotationView *annotationView = (MKAnnotationView *) [self.myMapView
                                                         dequeueReusableAnnotationViewWithIdentifier:annotationIdentifier];

if (!annotationView)
{
    annotationView = [[MKAnnotationView alloc]
                      initWithAnnotation:annotation
                      reuseIdentifier:annotationIdentifier];

    NSString *restaurant_Icon = ((Annotation *)annotation).AnnotationPicture;
    NSString *restaurant_Callout = [NSString stringWithFormat:@"mini.%@",restaurant_Icon];

    UIImage *oldImage = [UIImage imageNamed:restaurant_Icon];
    UIImage *newImage;
    CGSize newSize = CGSizeMake(75, 75);

    newImage = [oldImage imageScaledToFitSize:newSize]; // uses MGImageResizeScale


    annotationView.image= newImage;

    annotationView.canShowCallout = YES;

    UIImage *Mini_oldImage = [UIImage imageNamed:event_Callout];
    UIImage *Mini_newImage;
    CGSize Mini_newSize = CGSizeMake(30,30);

    Mini_newImage = [Mini_oldImage imageScaledToFitSize:Mini_newSize]; // uses MGImageResizeScale

    UIImageView *finalMini_callOut = [[UIImageView alloc] initWithImage:Mini_newImage];
    annotationView.leftCalloutAccessoryView = finalMini_callOut;


    UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];


    annotationView.rightCalloutAccessoryView = rightButton;

}
else
{
    annotationView.annotation = annotation;
}

return annotationView;
}
4

1 回答 1

1

如果没有别的，您将根据注释设置图标和标注，但仅在viewForAnnotation注释未出列时才这样做。您真的想在 if 块之外进行任何特定于注释的自定义，以防重复使用注释视图。

与您报告的问题无关，还有其他一些观察结果：

  1. 您可能应该retrieveData异步执行，这样您就不会将主线程与数据检索/解析捆绑在一起。继续将条目添加到您的数组并将注释添加到主队列中的地图，但是网络内容绝对应该异步完成。

  2. 您可能应该检查以确保data不是nil（例如没有网络连接或其他一些网络错误），因为JSONObjectWithData如果您传递一个nil值会崩溃。

  3. 您的使用locations似乎没有必要，因为您正在为 JSON 中的每个条目重置它。您可以（a）locations完全退休，只需将myAnn对象添加到地图的注释中；或 (b)在循环locations之前初始化。for但是维护这个 ivar 可能会产生误导，而只用最后一个注释填充它。

于 2013-07-30T01:24:38.940 回答