地图/*进行反向地理位置解析*/

error == The operation couldn’t be completed. (kCLErrorDomain error 8.)

Number 8 is "kCLErrorGeocodeFoundNoResult", so I suspect you're searching for something with no results. I've read elsewhere that CLGeocoder only runs on a device (not the simulator) but I haven't verified it myself. If you are sure your search string should get results, try your code on a device.
---结果为空的意思

/*进行反向地理位置解析*/
- (void)geocodeAddressString:(NSString *)addressString inRegion:(CLRegion *)inRegion
{
    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 5.0) {//IOS5.0及以上系统
        [_geocoder cancelGeocode];
        if (_geocoder == nil) {
            _geocoder = [[CLGeocoder alloc] init];
        }
        
        self.isGeocoding = YES;
        if (inRegion) { //有搜索范围
            [_geocoder geocodeAddressString:addressString inRegion:inRegion completionHandler:^(NSArray *placemarks, NSError *error) {
                if (error) {
                    //[self failGeocodeAddress];
                } else {
                   // [self geocodeAddressLocation:placemarks];
                }
            }];
        } else { //无搜索范围
            [_geocoder geocodeAddressString:addressString completionHandler:^(NSArray *placemarks, NSError *error) {
                NSLog(@"======%@",placemarks);
                if (error) {
                    NSLog(@"error == %@",error.localizedDescription);
                   // [self failGeocodeAddress];
                } else {
                    //[self geocodeAddressLocation:placemarks];
                }
            }];
        }
    }
}

/*进行反向地理位置解析*/
- (void)geocodeAddressString:(NSString *)addressString
{
    [self geocodeAddressString:addressString inRegion:nil];
}