Null output troubles - cocoa-touch

Question

Okay I've been trying at this for about 2-3 hours now and I don't seem to quite get it. Here is the code and a brief explanation:
I'm trying to make two lists of words, pull one word from each of those lists at random, and display both words (along with a third) on the screen when a button is pressed. Here is the code:
#import "Project001ViewController.h"
#implementation Project001ViewController
-(ArrayOfWords *) advs
{
if(!advs){
advs = [[ArrayOfWords alloc] init];
NSString* advpath = #"/WordLists/adverbs.txt";
NSLog(#"1");
[[self advs] populateListOfWords:advpath];
}
return advs;
}
-(ArrayOfWords *) adjs
{
if (!adjs) {
adjs = [[ArrayOfWords alloc] init];
NSString* adjpath = #"/WordLists/adjectives.txt";
[[self adjs] populateListOfWords:adjpath];
NSLog(#"2");
}
return adjs;
}
- (IBAction)generate:(UIButton *)sender;
{
//int randy = arc4random() % 11;
//NSNumber* num= [NSNumber numberWithInteger:randy];
NSString* obj = #"app";
NSString* adverb = [[self advs] randomItem];
NSString* adjective = [[self adjs] randomItem];
NSLog(#"%i %i",[adjs size],[advs size]);
NSLog(#"1 %# %# %#.",adverb, adjective, obj);
//NSLog(#"%#",thePhrase);
[display setText:#"Hi"];
}
#end
I'm having trouble on the last NSLog line:
NSString* obj = #"app";
NSString* adverb = [[self advs] randomItem];
NSString* adjective = [[self adjs] randomItem];
NSLog(#"%i %i",[adjs size],[advs size]);
NSLog(#"1 %# %# %#.",adverb, adjective, obj);
Instead of getting the two randomly selected words (using arc4random() to produce them) the array returns Null. But I know FOR CERTAIN. That the array's are not empty because the NSLog Line where I print [adjs size] and [advs size] I get the correct sizes of the list of words. I just want to know what is causing them to print Null here.
populateListOfWords, randomItem, and size methods:
- (NSArray *) populateListOfWords:(NSString *) path {
//gets the components of the file into an NSString
NSString *wordListString = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
//returns an array of all the words (uses the next line indicator '\n' to know when it's at the end of the word
NSArray* words = [wordListString componentsSeparatedByString:#"\n"];
length=(NSNumber*)([words count]);
return words;
}
-(NSString*) randomItem{
//returns random object in list
return (NSString*)[list objectAtIndex:(arc4random() % (int)length)] ;
}
-(int) size{
//returns size of list
return (int)length;
}
(If more code is needed let me know and thank you in advanced for any and all help).

Answer 1

I believe there is a problem with the paths. It is impossible to have access to the path /WordLists/adjectives.txt in iOS due to the application sandbox. I suggest you add these files to the application by dragging and dropping them onto the project. You can get the file paths for resources in application bundle using
NSString * path = [[NSBundle mainBundle] pathForResource:#"adjectives" ofType:#"txt"];
Now pass this path to the method populateListOfWords:.
Because of the incorrect path, I believe wordListString is nil and everything else follows to be that.
Another thing is that int and NSNumber are not toll free bridged like NSStrings and other foundation objects. So
length=(NSNumber*)([words count]);
is incorrect. I suggest you define length as int or better NSUInteger to match the type count method returns.

Answer 2

This method is the problem:
- (NSArray *) populateListOfWords:(NSString *) path {
//gets the components of the file into an NSString
NSString *wordListString = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
//returns an array of all the words (uses the next line indicator '\n' to know when it's at the end of the word
NSArray* words = [wordListString componentsSeparatedByString:#"\n"];
length=(NSNumber*)([words count]);
return words;
}
It wasn't actually putting the words in a list that anyone else could access. I had to just modify it like so:
- (void) populateListOfWords:(NSString *) path {
//gets the components of the file into an NSString
NSString *wordListString = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
//returns an array of all the words (uses the next line indicator '\n' to know when it's at the end of the word
NSArray* words = [wordListString componentsSeparatedByString:#"\n"];
list = words;
length=(int)([words count]);
}
Now it gives me the correct output. But for some reason when I press the button twice it crashes. Oh well that's a new problem. Thanks again for all the help.
UPDATE
Turns out advs and adjs were being released so the second go around it was trying to access a nil value because when I call [self advs] [self adjs] the pointers exist, but their contents do not. I had to go back and refill them each time basically removing the if (!advs) and if (adjs) parts. It now works as intended.