brandontreb.comCode, Nerdyness, and Nonsense

If you have ever coded Java, you know how important the toString() method is.  Well, objective-c has a similar method called Description. What overriding the description will allow you to do is, customize the output when you want to print your object.

Let’s take an example where you might have a class called User that contains a few properties.

@interface User : NSObject {
	NSInteger userID;
	NSString  *name;
	NSString  *website;
}
@end

Now, at this point if we did

NSLog(@"%@",user);

we would end up with output like

User: 0xd18f50

which is not very helpful.  What would be better is when we want to print the user for it to display their userID, name, and website.  This can be done by overriding the description method like this.

-(NSString *) description {
	return [NSString stringWithFormat:@"ID: %d\nName: %@\nWebsite: %@\n",
			userID,name,website];
}

Now when we call

NSLog(@"%@",user);

is will nicely display this:

ID: 42
Name: brandontreb
Website: http://brandontreb.com

Note: NSLog is your best friend when debugging any objective-c application. Use it often. Also, to open up the Debugger Console, click Run -> Console.

Tags: debugger console, java tostring, objective-c programming, objectivec tostring

This entry was posted on Monday, July 27th, 2009 at 8:47 am and is filed under Code. You can follow any comments to this entry through the RSS 2.0 feed. You can leave a comment, or trackback from your own site.