Implementing countByEnumeratingWithState:objects:count:
If you want to use fast enumeration on your own classes, you must implement
-
-
Objective-C 2.0: Fast enumeration clarifications
Fast enumeration in Objective-C 2.0 is a doubly useful addition: it results in code that looks better and runs faster. Its documentation though, still contains a few points which are ambiguous or misleading. Here are some clarifications that I've uncovered.
-
Square Root: Numerical fun with NSDecimalNumber
NSDecimalNumber is a powerful Foundation class that holds high precision base 10 numbers. The default class only provides basic arithmetic operators, leaving you to write any advanced operations that you need. This is an example that implements a square root using NSDecimalNumber.
-
Open the previous document on application startup
Setting up your application to open the most recent document on startup is easier than you might think. Here's a quick solution with a some code you can plug straight into your app.
-
Propagate deletes immediately in Core Data
Learn some limitations associated with cascading deletes in Core Data and find out how to immediately propagate deletes in Core Data, overcoming these potential problems.
-
viewWillDraw - a welcome addition to NSView in 10.5
A method named viewWillDraw appeared in NSView in Mac OS X 10.5. If you have cause to use it, this method replaces 6 other methods from earlier versions of Mac OS X. Read more to find out if you should use it and how it helps.
-
Type punning isn't funny: Using pointers to recast in C is bad.
A very common C technique for reinterpreting data types has the potential to cause nasty bugs. Apple knows this, which is why the implementation of NSRectToCGRect (correctly) doesn't do what the documention claims. I show you a technique to perform reinterpret casts safely in your own code.
-
The value of immutable values
This is an explanation of why Cocoa contains immutable value classes and why the value classes you create in your own program should be immutable too.
-
Supersequent implementation
Ever wanted to override a method using a category but still invoke the default method from the category? Like invoking the super method on a super class, this example will show you how to invoke any "supersequent" method no matter if its on the super class, the current class or even another category on the current class.
-
Testing Core Data with very big hierarchical data sets
I test Core Data's performance with a one million object data set stored in a basic three-tiered hierarchy. I look at the performance when building, loading, fetching and traversing.