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我正在尝试删除地图的所有注释。包含MKMapView实现的类MKMapViewDelegate。单击按钮（显示在模式视图中）时，我正在调用删除所有注释方法。我正在使用下一个代码来删除所有注释。

- (void)removeAllAnnotations {

 NSMutableArray *annotationsToRemove = [NSMutableArray arrayWithCapacity:[self.mapView.annotations count]];
 for (int i = 0; i < [self.mapView.annotations count]; i++) {
  if ([[self.mapView.annotations objectAtIndex:i] isKindOfClass:[AddressAnnotation class]]) {
   [annotationsToRemove addObject:[self.mapView.annotations objectAtIndex:i]];
  }
 }

 [self.mapView removeAnnotations:annotationsToRemove];
}

代码可以正常工作，但是在调用该方法之后，当我尝试向空地图添加新注释时，该类不会调用该viewForAnnotations方法，并且注释不会下拉并且不会在注释视图中显示披露按钮。为什么会这样？

谢谢阅读。

编辑：

显示了注释，但没有调用注释方法的视图（没有下拉并且没有在注释视图中包含披露按钮）。这是我用来添加注释的方法和viewForAnnotation方法。

- (void)loadAnnotations:(NSString *)type {

    NSString *path = [[NSBundle mainBundle] pathForResource:@"PlacesInformation" ofType:@"plist"];
    NSMutableArray *tmpArray = [[NSMutableArray alloc] initWithContentsOfFile:path];

    for (int i = 0; i < tmpArray.count; i++) {

        // Breaks the string down even further to latitude and longitude fields.
        NSString *coordinateString = [[tmpArray objectAtIndex:i] objectForKey:@"coordinates"];

        NSString *option = [[tmpArray objectAtIndex:i] objectForKey:@"type"];               
        if ([option isEqualToString:type]) {
            CLLocationCoordinate2D currentCoordinate = [self stringToCoordinate:coordinateString];
            AddressAnnotation *annotation = [[[AddressAnnotation alloc] initWithCoordinate:currentCoordinate] autorelease];
            [self.mapView addAnnotation:annotation];
        }
    }
}

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

    // If it's the user location, just return nil.
    if ([annotation isKindOfClass:[MKUserLocation class]])
        return nil;
    else { // Handles the other annotations.
        // Try to dequeue an existing pin view first.
        static NSString *AnnotationIdentifier = @"AnnotationIdentifier";
        MKPinAnnotationView *pinView = (MKPinAnnotationView *)[self.mapView dequeueReusableAnnotationViewWithIdentifier:AnnotationIdentifier];

        if (!pinView) {
            // If an existing pin view was not available, creates one.
            MKPinAnnotationView *customPinView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:AnnotationIdentifier] autorelease];
            customPinView.animatesDrop = YES;
            customPinView.canShowCallout = YES;

            // Adds a detail disclosure button.
            UIButton *rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
            [rightButton addTarget:self action:@selector(showDetails:) forControlEvents:UIControlEventTouchUpInside];
            customPinView.rightCalloutAccessoryView = rightButton;

            return customPinView;
        } else
            pinView.annotation = annotation;
    }

    return nil;
}
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1 回答 1

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在 viewForAnnotation 中，在您重用视图的情况下，您当前返回 nil。

这其他部分：

} else
    pinView.annotation = annotation;

应该是：

} else {
    pinView.annotation = annotation;
    return pinView;
}
于 2010-11-26T16:35:57.730 回答