ErrorFormatter.h

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

@interface ErrorFormatter : NSObject

@property (strong, nonatomic) NSError *error;

- (id)initWithError:(NSError *)error;

- (UIAlertView *)alert;

- (NSString *)message;
- (NSString *)title;

@end

ErrorFormatter.m

#import "ErrorFormatter.h"

@implementation ErrorFormatter

- (id)initWithError:(NSError *)error {
    self = [self init];
    if (self) {
        self.error = error;
    }
    return self;
}

- (UIAlertView *)alert {
    return [[UIAlertView alloc] initWithTitle:[self title]
                                      message:[self message]
                                     delegate:nil
                            cancelButtonTitle:NSLocalizedString(@"controls.ok", nil)
                            otherButtonTitles:nil];
}

- (NSString *)message {
    return [[NSBundle mainBundle] localizedStringForKey:[self keyWithType:@"message"]
                                                  value:[self defaultMessage]
                                                  table:nil];
}

- (NSString *)title {
    return [[NSBundle mainBundle] localizedStringForKey:[self keyWithType:@"title"]
                                                  value:[self defaultTitle]
                                                  table:nil];
}

- (NSString *)defaultMessage {
    if ([self.error localizedRecoverySuggestion]) {
        return [self.error localizedRecoverySuggestion];
    } else {
        return [self.error localizedDescription];
    }
}


- (NSString *)defaultTitle {
    if ([self.error localizedFailureReason]) {
        return [self.error localizedFailureReason];
    } else {
        return NSLocalizedString(@"errors.title", nil);
    }
}

- (NSString *)keyWithType:(NSString *)type {
    return [NSString stringWithFormat:@"errors.%@.%d.%@", self.error.domain, self.error.code, type];
}

@end

gistfile1.m

- (void)mapView:(MKMapView *)mapView didFailToLocateUserWithError:(NSError *)error {
    ErrorFormatter *formatter = [[ErrorFormatter alloc] initWithError:error];
    UIAlertView *alert = [formatter alert];
    [alert show];
}

Localizable.strings

// Errors
"errors.title" = "Error";
"errors.kCLErrorDomain.0.title" = "Unknown Location";
"errors.kCLErrorDomain.0.message" = "Couldn't get a good reading. Long tunnel?";
"errors.kCLErrorDomain.2.title" = "No Internet";
"errors.kCLErrorDomain.2.message" = "Internet is unavailable or an error occured";
"errors.kCLErrorDomain.8.title" = "No results found";
"errors.kCLErrorDomain.8.message" = "";
"errors.kCLErrorDomain.9.title" = "No results found";
"errors.kCLErrorDomain.8.message" = "";

ErrorFormatter

Thin wrapper around NSError which lets you define custom strings or defaults to NSError localized strings.

Features

• Optionally define titles and messages in Localizable.strings.
• Missing titles default to localizedFailureReason or NSLocalizedString(@"errors.title", nil)
• Missing messages default to localizedRecoverySuggestion or localizedDescription.

Screenshot