Question

我正在申请将引脚/注释放在mapview中。当用户靠近引脚时，我希望引脚改变颜色。一切正常，引脚放在我想要的地方，当我足够接近时，我收到一条警告信息。但我不知道如何更新引脚颜色。我是否必须删除注释并替换它们？似乎没必要，我正在寻找的是某种更新/刷新mapview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];

位置是CLLocationCoordinate2D
rows是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;
    }

}

Answer 1

您需要制作一个循环，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一个例子

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位置数组。有它 [mapView.userLocation.location distanceFrom：prox] /1609.334 // prox表示经过测试的位置实例，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;
}

如何将针脚放入我的mapview后更新/更改它的颜色？

1 个答案: