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Re: Objects return nil
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Re: Objects return nil


  • Subject: Re: Objects return nil
  • From: Michael Hanna <email@hidden>
  • Date: Thu, 7 Aug 2003 13:49:03 -0400

Thank you all for pointing this out..

I think the main problem is I was taught programming on Java and I had come to depend on the Java compiler warnings. A bad habit, I know.

Michael


On Thursday, August 7, 2003, at 12:30 PM, Jonathan Jackel wrote:

- (id)init
{
self = [super init];
linesPath = [[NSBundle mainBundle] pathForResource:@"lines"
ofType:@"plist"];
lineDict = [NSDictionary dictionaryWithContentsOfFile: linesPath];
key = @"lines"; // key to get lineArray from the
NSDictionary
tokenString = @"%s"; // the 12 tokens to be replaced within the
while-loop
tokenLines = [lineDict objectForKey:key];
NSLog(@"tokenLines: %@", tokenLines); // p/o the
contents fine

return self;
}

tokenLines becomes nil at the end of the event loop because you don't retain
what it points to. You should have done:

tokenLines = [[lineDict objectForKey:key] retain];

You need to brush up on retain and release. Search on cocoa.mamasam.com and
you will find a number of references to useful articles.


Why do my objects return nothing? Also, the NSArray returned is
retrieved as an NSMutableArray. Is explicit casting necessary?

You can return a mutable array even if your method says it returns an
immutable array. No casting is required. It won't work the other way
around, though.

Jonathan
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