How to add UIAlertView upon successfully saving a file

Question

How can I add a UIAlertView that will appear only if successfully saving my coordinates to the text file, thanks so much.

I just updated the post with all the code & wonder if you can see why it is showing the alert view twice.

Thanks.

#import "ViewController.h"


@interface ViewController ()
@end

@implementation ViewController {
CLLocationManager *locationManager;
}

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
locationManager = [[CLLocationManager alloc] init];
}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

- (IBAction)getCurrentLocation:(id)sender {
locationManager.delegate = (id)self;
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
[locationManager startUpdatingLocation];
}

#pragma mark - CLLocationManagerDelegate

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
NSLog(@"didFailWithError: %@", error); UIAlertView *errorAlert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"Failed to Get Your Location" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; [errorAlert show];
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
NSLog(@"Location updated: %@", newLocation);
CLLocation *currentLocation = newLocation;

if (currentLocation != nil) {
    _LatitudeLabel.text = [NSString stringWithFormat:@"%.8f", currentLocation.coordinate.latitude];
    _LongitudeLabel.text = [NSString stringWithFormat:@"%.6f", currentLocation.coordinate.longitude];
    _GPSAccuracyLabel.text = [NSString stringWithFormat:@"%.2f", currentLocation.horizontalAccuracy];
    _AltitudeLabel.text = [NSString stringWithFormat:@"%.2f", currentLocation.altitude];
    _VerticalAccuracyLabel.text = [NSString stringWithFormat:@"%.2f", currentLocation.verticalAccuracy];
}

NSString *newLocString = [NSString stringWithFormat:@"%s%f\n%s%f","Lat=",currentLocation.coordinate.latitude,"Long=",currentLocation.coordinate.longitude];
NSString *path = @"var/mobile/Documents/location.txt";
NSError *error = nil;
// Save string and check for error
if (![newLocString writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:&error]) {
    NSLog(@"An Error occurred: %@", error.localizedDescription);
} else {
    UIAlertView *savedAlert = [[UIAlertView alloc] initWithTitle:@"File saved"message:@"File saved successfully" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [savedAlert show];
}

/* IOS8

 else {
 // Create the alert itself
 UIAlertController *savedAlert = [UIAlertController alertControllerWithTitle:@"File saved" message:@"File saved successfully" preferredStyle:UIAlertControllerStyleAlert];

 // Create the "OK" button 'Action'
 UIAlertAction *defaultAction = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action) {}];

 // Add the 'Action' created above, to our alert (otherwise, we won't have any button in it)
 [savedAlert addAction:defaultAction];

 // Presents the alert
 [self presentViewController:savedAlert animated:YES completion:nil];
 }

 ======================================

 FOR IOS 7

 else {
 UIAlertView *savedAlert = [[UIAlertView alloc] initWithTitle:@"File saved"message:@"File saved successfully" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
 [savedAlert show];
 }
 */

// Stop Location Manager
[locationManager stopUpdatingLocation];
}

@end

Answer 1

You already have an if statement that checks if there was error when trying to save the file.
Just add an else statement, meaning the file saved successfully, that shows the UIAlertView

Change your code to the following:

EDIT- Since UIAlertView is deprecated in iOS 8, I've modified the code so it'll work both on iOS 8 and on prior versions.

// Save string and check for error  
if (![newLocString writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:&error]) {  
    NSLog(@"An Error occurred: %@", error.localizedDescription);  
} else {  

    // Here we are receiving a string which holds the iOS version
    NSString *iOSversion = [[UIDevice currentDevice] systemVersion];  

    // Here we are comparing the above string, to the string "7.2"  
    // Since both are string, and not numbers, we are using the option 'NSNumericSearch'  
    // I've randomly chosen version 7.2, since iOS 7 latest version is 7.1.2,  
    // Every version number below 7.2 will be prior to iOS 8, and above 7.2 will be iOS 8  
    // If I would've chosen the latest iOS 7 version, which is 7.1.2, or the first iOS 8 version  
    // which is 8.0, I would have needed to add code which my comparison results will be NSOrderedSame  
    // Note that the comparison just gives me the order in which the below items will be, compared to one another
    if([iOSversion compare:@"7.2" options:NSNumericSearch] == NSOrderedAscending) {
        UIAlertView *savedAlert = [[UIAlertView alloc] initWithTitle:@"File saved"  
                                                             message:@"File saved successfully"  
                                                             delegate:nil  
                                                    cancelButtonTitle:@"OK"  
                                                    otherButtonTitles:nil];  
        [savedAlert show];  
    } else {
        // Create the alert itself
        UIAlertController *savedAlert = [UIAlertController alertControllerWithTitle:@"File saved"  
                                                                            message:@"File saved successfully"  
                                                                     preferredStyle:UIAlertControllerStyleAlert];

        // Create the "OK" button 'Action'
        UIAlertAction *defaultAction = [UIAlertAction actionWithTitle:@"OK"  
                                                                style:UIAlertActionStyleDefault  
                                                              handler:^(UIAlertAction * action) {}];

        // Add the 'Action' created above, to our alert (otherwise, we won't have any button in it)  
        [savedAlert addAction:defaultAction];

        // Presents the alert
        [self presentViewController:savedAlert animated:YES completion:nil];  
    }
}