CS193P - Lecture 14
iPhone Application Development
Debugging Tips
CoreFoundation
Searching
Notifications
Announcements
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Presence 3 was due last night at midnight
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Ask if you’re not sure how many late days you’ve used
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Presence 4 is out today, due Wednesday 11/12
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Expect final project proposal feedback this week
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Final projects due week of 12/5
Today’s Topics
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Debugging Tips
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CoreFoundation
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Searching
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Notifications
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Tab Bar + Navigation Controllers (Review)
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Presence 4
Debugging Tips
Messaging Nil
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Remember, sending a message to nil is valid in Objective-C
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Has no effect, returns nil/zero
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Won’t crash, log or throw an exception
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Very convenient, avoid repetitive checks
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But it can be a source of subtle bugs
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When debugging, ensure you’re not unexpectedly messaging nil
NSArray *array = nil;
// Forget to initialize array
[array addObject:someObject];
NSLog(@“%d”, [array count]); // Prints 0
// Spend 5 hours debugging and going crazy
