从 MapView Delegate 方法获取错误注释

Question

我在 .h 文件中声明了以下内容：

Annotation *annoForMoreDetails。

但是，当我尝试将其设置为方法中的当前注释时

- (MKAnnotationView *)mapView:(MKMapView *)mapViews viewForAnnotation:(id)annotation

它被设置为错误的对象。

这是我的代码：

 - (MKAnnotationView *)mapView:(MKMapView *)mapViews viewForAnnotation:(id <MKAnnotation> )annotation
{
    NSLog(@"welcome into the map view annotation");
    // if it's the user location, just return nil.
    if ([annotation isKindOfClass:[MKUserLocation class]])
        return nil;
    for (annotation in [mapView annotations]) {
        if ([[mapView annotations] containsObject:annotation]) {
            annoForMoreDetails = annotation;
        }
    }
    if (annoForMoreDetails.coordinate.latitude != mapViews.userLocation.coordinate.latitude && annoForMoreDetails.coordinate.longitude != mapViews.userLocation.coordinate.longitude) {
    // try to dequeue an existing pin view first
    static NSString* AnnotationIdentifier = @"AnnotationIdentifier";
    MKPinAnnotationView* pinView = [[[MKPinAnnotationView alloc]
                                     initWithAnnotation:annotation reuseIdentifier:AnnotationIdentifier] autorelease];
    pinView.animatesDrop=YES;
    pinView.canShowCallout=YES;
    pinView.pinColor = MKPinAnnotationColorGreen;

    UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
    [rightButton setTitle:annotation.title forState:UIControlStateNormal];
    [rightButton addTarget:self
                    action:@selector(moreDetails)
          forControlEvents:UIControlEventTouchUpInside];
    pinView.rightCalloutAccessoryView = rightButton;
    return pinView;
    }
    else if (annoForMoreDetails.coordinate.latitude == mapViews.userLocation.coordinate.latitude && annoForMoreDetails.coordinate.longitude == mapViews.userLocation.coordinate.longitude) {
        return nil;
    }
    return nil;
}

- (void)moreDetails {
    annotationCalloutView.frame = CGRectMake(70, 120, 188, 218);
    annotationCalloutView.alpha = 0.0;
    mapView.userInteractionEnabled = NO;
    annotationCalloutView.userInteractionEnabled = YES;
    titleLabel.text = annoForMoreDetails.title;
    titleLabel.numberOfLines = 0;
    titleLabel.userInteractionEnabled = NO;
    addressLabel.text = annoForMoreDetails.subtitle;
    [self.view addSubview:annotationCalloutView];
    [UIView beginAnimations:@"callout" context:NULL];
    [UIView setAnimationDuration:0.6];
    annotationCalloutView.alpha = 1.0;
    [UIView commitAnimations];
}

如果您发现任何错误，请指出！

Answer 1

您是否尝试使用 annoForMoreDetails 来了解用户点击了哪个注释，以便您可以显示更多详细信息？如果是这样的话，还有一个更简单的方法。使用地图视图的 calloutAccessoryControlTapped 委托方法。当用户点击附件按钮时它将被调用，并且它将传递包含注释作为属性的注释视图。

删除 annoForMoreDetails 实例变量，并在 viewForAnnotation 中删除设置 annoForMoreDetails 的 for 循环（我认为最终每次都会将其设置为最后一个注释）。删除对 annoForMoreDetails 的所有其他引用。

同样在 viewForAnnotation 中，删除 rightButton 上的 addTarget 行，因为您将用 calloutAccessoryControlTapped 的实现替换自定义的 moreDetails 方法：

- (void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view 
    calloutAccessoryControlTapped:(UIControl *)control
{
    Annotation *annoForMoreDetails = (Annotation *)view.annotation;

    //the code currently in moreDetails method goes here...
}