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我正在制作一个将图钉/注释放在地图视图中的应用程序。当用户接近某个图钉时，我希望图钉改变颜色。一切正常，引脚放置在我想要的位置，当我足够接近时，我会收到一条警报消息。但我不确定如何更新引脚颜色。我必须删除注释并替换它们吗？似乎没有必要，我正在寻找的只是某种更新/刷新地图视图而无需替换注释。

CLLocation *place =[[CLLocation alloc] initWithCoordinate:location altitude:1 horizontalAccuracy:1 verticalAccuracy:-1 timestamp:nil];
    AddresAnnotation *ann = [[AddresAnnotation alloc] initWithCoordinate:place.coordinate];
    [ann setTitle:[rows placeName]];
    [mapView addAnnotation:ann];

location 是一个 CLLocationCoordinate2D
rows 是一个包含不同位置及其信息的对象

这是 mapView 委托方法：（不确定为什么最后一个“}”在代码示例之外）

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

    if (annotation != self.mapView.userLocation) {
        annView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"Plats"] autorelease];
        [annView setPinColor:MKPinAnnotationColorRed];
        annView.animatesDrop = TRUE;
        annView.canShowCallout = YES;
        return annView;
    } else {
        zoomButton.enabled = TRUE;
        return nil;
    }

}

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1 回答 1

0

您需要创建一个循环来测试该位置是否在用户的 x 英里范围内。这是我在自己的代码中使用的意思的示例

for (CLLocation *prox in locations) {
    NSLog(@"prox %@", prox);
    float distanceFromLocation = [mapView.userLocation.location distanceFromLocation:prox]/1609.344;
    NSLog(@"distance %f", distanceFromLocation);
    if (distanceFromLocation <= 10) {
        NearbyLocation *nearbyLocation = [[NearbyLocation alloc]init];
        NSString *key = [NSString stringWithFormat:@"%d", index];
        nearbyLocation.title = [storedTitles objectForKey:key];
        nearbyLocation.loction = prox;
        nearbyLocation.subtitle = [NSString stringWithFormat:@"%.1f miles away", distanceFromLocation];
        nearbyLocation.lat = prox.coordinate.latitude;
        nearbyLocation.lon = prox.coordinate.longitude;
        [newArray addObject:nearbyLocation];
        [nearbyLocation release];
    }
    index++;
}
NSLog(@"new array %d prox %d", [newArray count], [proximityOutlet.nearbyLocations count]);
if ([newArray count] > [proximityOutlet.nearbyLocations count]) {
    NSLog(@"set array");
    // if the new array has actually added any objects, set the array and switch views;
    proximityOutlet.nearbyLocations = newArray;
    //[self.navigationController pushViewController:proximityOutlet animated:YES];
    proximityOutlet.modalPresentationStyle = UIModalPresentationPageSheet;
    proximityOutlet.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
    [self presentModalViewController:proximityOutlet animated:YES];
}
[newArray release];

}

基本上，创建一个循环来搜索一系列位置。拥有它 [mapView.userLocation.location distanceFrom:prox]/1609.334 //prox 代表一个位置实例，该位置经过测试以查看用户是否在 x 英里范围内。

然后说

if ([mapview.userLocation.location distanceFrom:prox]/1609.334 < (however many miles)){

        annotationView = x;
}
于 2011-06-16T04:51:41.567 回答