Question

This is the problem code:

NSURL *url = [NSURL URLWithString:@"http://photostiubhart.comoj.com/ReadGallery/stiubhart1readgallery.php"];
NSError* error; 
NSString* sizeString = [NSString stringWithContentsOfURL:url encoding:NSASCIIStringEncoding error:&error];
double myDouble = [sizeString doubleValue];
int myInt = (int)(myDouble + (myDouble>0 ? 0.5 : -0.5));

//Create an array to hold the URLS
NSMutableArray *myURLS;

//Initialize the array with nil
myURLS = [[NSMutableArray alloc] init];

NSLog(@"Here1");
//Add all the URLs from the server to the array
for (int i = 0; i <= myInt; i++){
    NSString *tempString = [[NSString alloc] initWithFormat : @"http://photostiubhart.comoj.com/GalleryImages/%dstiubhart1.jpg", i];
    [myURLS addObject: [NSURL URLWithString:tempString]];
    [tempString release];
}

myPhotos = [[NSMutableArray alloc] init];

for(int i = 0; i < myInt; i++){
    [myPhotos addObject:[myURLS objectAtIndex:i]];
}

It gives the error:

2011-06-21 22:20:47.167 CHARLIE[666:207] -[NSURL length]: unrecognized selector sent to instance 0x70418c0

This is what the code does (at least supposed to):

1. Generate an integer from the contents of the URL (“4”).
2. Use the integer in the for loops to add objects to arrays.

Can anyone tell me whats wrong here?

Thanks a lot,

Jack

Answer 1

If you want to add URLs as strings then shouldn’t this –

for (int i = 0; i <= myInt; i++){
    NSString *tempString = [[NSString alloc] initWithFormat : @"http://photostiubhart.comoj.com/GalleryImages/%dstiubhart1.jpg", i];
    [myURLS addObject: [NSURL URLWithString:tempString]];
    [tempString release];
}

be –

for (int i = 0; i <= myInt; i++){
    NSString *tempString = [NSString stringWithFormat:@"http://photostiubhart.comoj.com/GalleryImages/%dstiubhart1.jpg", i];
    [myURLS addObject:tempString];
}

You’re probably expecting them to be strings and later calling length method on them whereas they are stored as URLs in the array.

Additionally, myPhotos seems to be a property in which case you can substitute –

myPhotos = [[NSMutableArray alloc] init];

for(int i = 0; i < myInt; i++){
    [myPhotos addObject:[myURLS objectAtIndex:i]];
}

with this –

self.myPhotos = myURLS;
[myURLS release]; // To balance out the earlier alloc-init