Question

I have a .xib file where the user can enter a location name of a place in a UITextField and click search. Then another .xib file will load where the user will see a MapView object with the location on the map.

I made a custom init method where I pass the string as follows when the user clicks the button:

AddLocViewController *locView = [[AddLocViewController alloc] initWithNibName:nil bundle:nil customLoc:textLoc.text];
[self presentModalViewController:locView animated:YES];

In the new ViewController class called AddLocViewController.m the init method and viewDidLoad is as following:

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil customLoc:(NSString*)_loc
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) 
    {
        stringLoc1 = _loc;
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];    
    [self showAddress];
}

Here [self showAddress] calls a method to display the contents on the mapView object, The showAddress method works perfectly if I have a UITextField taking input and clicking a button to set the value to a NSString object stringLoc and using that in showAddress method:

- (void) showAddress
{
    MKCoordinateRegion region;
MKCoordinateSpan span;

span.latitudeDelta=0.01f;
span.longitudeDelta=0.01f;

    stringLoc1 = [NSString stringWithFormat:@"http://maps.google.com/maps/geo?q=%@&output=csv", 
                       [addressField.text stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];

    NSString *locationString = [NSString stringWithContentsOfURL:[NSURL URLWithString:stringLoc1]];
NSArray *listItems = [locationString componentsSeparatedByString:@","];

double aLatitude = 0.0;
double aLongitude = 0.0;

if([listItems count] >= 4 && [[listItems objectAtIndex:0] isEqualToString:@"200"]) {
    aLatitude = [[listItems objectAtIndex:2] doubleValue];
    aLongitude = [[listItems objectAtIndex:3] doubleValue];
}
else {
    [addressField setText: @"Address Location error"];
    return;
}

[addressField resignFirstResponder];

CLLocationCoordinate2D location = {latitude: aLatitude, longitude:aLongitude};

region.span=span;
region.center.latitude = aLatitude;
    region.center.longitude = aLongitude;

    if(addAnnotation != nil) {
    [mapView removeAnnotation:addAnnotation];
    //[addAnnotation release];
    addAnnotation = nil;
}

    addAnnotation = [[AddressAnnotation alloc] initWithCoordinate:location];
    [mapView addAnnotation: addAnnotation];

[mapView setRegion:region animated:TRUE];
[mapView regionThatFits:region];
}

Please help me pass parameter here to this class and use the showAddress method appropriately because it only now shows the proper location when a location is searched from within the class and does not show the proper location when instantiated.

Answer 1

Here you overwrite stringLoc1 with the content of the address field:
It is overwritten regardless of its initial value. If the textField is empty then it is overwirtten with an empty string.

stringLoc1 = [NSString stringWithFormat:@"http://maps.google.com/maps/geo?q=%@&output=csv", 
                       [addressField.text stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];

I am not sure what the best solution is in the context of your remaining code. But this should work:

NSString *currentLoc;

if (addressField.text && ([addressField.text length] == 0)) {
  currentLoc = addressFiled.text;
  stringLoc1 = addressField.text; // this line will set the current value as default value for the next call of the method; unless a new init call comes in between.
}
else
  currentLoc = stringLoc1; 


    currentLoc = [NSString stringWithFormat:@"http://maps.google.com/maps/geo?q=%@&output=csv", 
                           [currentLoc  stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];

NSString *locationString = [NSString stringWithContentsOfURL:[NSURL URLWithString:currentLoc ]];

I am sure there are smarter ways of doing that. But this should work with minimal changes to the view lines of code that you shared with us.