reverseGeocodeLocation Only Executes Completion Block Once

问题

I have an array of coordinates that I step through with a for loop. I would like to place annotations on a map for each location and have the subtitle for the callout be the address of the coordinate, found by using reverseGeocodeLocation In the for loop, I call the reverseGeocodeLocation method, and inside the completion block I create the annotation and display it on the map. However, when I run the app, only one annotation shows up. I went in the debugger, and the completion block is only getting called once (for two calls to the reverseGeocodeLocation method). Any suggestions to fix this?

My for loop:

for(int i = 0; i < [locations count]; i++)
{
    CLLocation *location = [locations objectAtIndex:i];
    __block NSString *info;
    NSLog(@"Resolving the Address");
    [geocoder reverseGeocodeLocation:location completionHandler:^(NSArray *placemarks, NSError *error)
    {
        NSLog(@"Found placemarks: %@, error: %@", placemarks, error);
        if (error == nil && [placemarks count] > 0)
        {
            placemark = [placemarks lastObject];
            info = [NSString stringWithFormat:@"%@ %@ %@ %@, %@",
                    placemark.subThoroughfare, placemark.thoroughfare,
                    placemark.postalCode, placemark.locality,
                    placemark.administrativeArea];
            [self remainderOfMethod:location withAddress:info atIndex:i];
        }
        else
        {
            NSLog(@"%@", error.debugDescription);
        }
    } ];
}

And the method called at the completion block:

- (void) remainderOfMethod: (CLLocation *)location withAddress:(NSString *)info atIndex: (int)i
{
     MKPointAnnotation* annotation = [[MKPointAnnotation alloc] init];
     if (location != nil)
     {
         [annotation setSubtitle:[NSString stringWithFormat:@"%@", info]];
         annotation.coordinate = location.coordinate;
         [self.mapView addAnnotation:annotation];
     }
}

Thanks!

回答1:

From the official Apple documentation:

After initiating a reverse-geocoding request, do not attempt to initiate another reverse- or forward-geocoding request

You can find the docs here: https://developer.apple.com/library/ios/documentation/CoreLocation/Reference/CLGeocoder_class/Reference/Reference.html#//apple_ref/occ/instm/CLGeocoder/reverseGeocodeLocation:completionHandler:

One way to solve it is to do only one request at a time in a recursive method that pops a location from a stack (or array) on each iteration.

Even in that case, consider what Apple has to say about it:

Geocoding requests are rate-limited for each app, so making too many requests in a short period of time may cause some of the requests to fail

So you may want to request geocoding on demand, for example when a user taps on an annotation.

来源：https://stackoverflow.com/questions/23072591/reversegeocodelocation-only-executes-completion-block-once

标签

ios

objective-c

cllocation