This post describes what is needed for any class to work as a key of NSDictionary or NSMutableDictionary. The only thing that is really required is that your class adopt the NSCopying protocol. Â That’s because every key is copied before being added to the dictionary. Â I mention why this design decision was probably made below. […]
UIScrollView bug
June 7 10
This post describes a bug in UIScrollView that occurs when you programmatically set the contentOffset with animation. Below is code to reproduce the bug; I’ve confirmed it’s in iPhone OS 3.2 but it may be in other versions as well. If you make a call to [scrollView setContentOffset:offset1 animated:YES]; and later make a call to […]
Event tracking stops NSTimer
May 30 10
NSTimers usually don’t fire when the user is scrolling a table or other UIScrollView – or doing anything else that puts the run loop in event tracking mode. Â This post describes the problem and an easy solution. The problem Suppose you set up a timer in the most convenient manner, with something like this: [NSTimer […]
Memory management guidelines
May 23 10
In this post, I’ll outline four simple rules for memory management in Objective-C. The Apple docs have already established basic guidelines for object ownership, following the fundamental idea that if you own an object, then you’re responsible for releasing it. This post goes a step further with tips for when and where ownership can be […]
Preprocessor debugging goodies
May 11 10
Ok, I admit it – my favorite debugging tool is still NSLog (and print statements in general). Â In this post I’ll mention some useful debug logging techniques you can use with the help of preprocessor macros. Logging method calls It’s as simple as this: #define PrintName NSLog(@”%s”, __FUNCTION__) Add this macro (with a semicolon) to […]