Archive

Archive for March, 2009

Learning iPhone from scratch

March 31st, 2009 No comments

I’ll talk more about it later, but the absolute best way to learn iPhone is to learn Mac first. That’s how I teach my classes. The available Mac educational resources are just much better, at least today.

The absolute gold standard for learning Cocoa on Mac is Cocoa Programming for Mac OS X by Aaron Hillegass. It is the book. I have a syllabus based on it that’s stripped down to the chapters that are useful for iPhone programmers. I’ll get that into a blog post.

When I teach this, it runs between 5 and 10 full days depending on how in-depth I cover the Mac side. Read more…

Categories: iphone Tags: ,

Memory Managing IBOutlets

March 22nd, 2009 No comments

Apple finally updated theĀ Memory Management Guide to deal with IBOutlets.

They came to the same recommendation that many of us have. Treat them exactly like other properties. Mark them as retain properties, release them in -dealloc, and overload -setView to clear them in low-memory situations. This last recommendation was one that many of us used, but was based on undocumented behaviors. Apple finally documented the behavior because there’s no other good way to do it given their internal implementation.

Unfortunately they haven’t updated the “Using View Controllers” documentation to include this stuff, and the section on how -loadView works is still a bit vague. I’ve sent them feedback on those pages.

Core Data vs. RDBMS

March 5th, 2009 1 comment

For those of you familiar with SQL and coming to Core Data, you probably want to separate the concept of “database” into the two kinds we’re discussing here. There are relational databases, which is what you’re probably used to, and object databases, which is what Core Data provides. Core Data happens to implement its object database on top of a relational database (SQLite), but that is a opaque implementation detail.

In a relational database, the key actions are the select and the transaction. In the select, you ask the database to form itself into a collection of columns (joins are just a fancy way of doing that), filter and sort itself according to some set of rules, and then return you a linear collection of rows. In the transaction, you inform the system that you are beginning a transaction, instruct the database to perform a series of transformations, and then commit or roll-back the transaction. It’s a great model, but Core Data doesn’t look much like it. Read more…

Categories: cocoa Tags: ,