IBOutlets

从历史上看，outlet的内存管理一直很差。 当前的最佳实践是将outlet声明为属性:

@interface MyClass :NSObject {
    NSTextField *textField;
}
@property (nonatomic, retain) IBOutlet NSTextField *textField;
@end

使用属性使内存管理语义清晰;如果使用实例变量综合，它还提供了一致的模式。

其中一些已经被提到过，但以下是我能想到的:

Follow KVO naming rules. Even if you don't use KVO now, in my experience often times it's still beneficial in the future. And if you are using KVO or bindings, you need to know things are going work the way they are supposed to. This covers not just accessor methods and instance variables, but to-many relationships, validation, auto-notifying dependent keys, and so on. Put private methods in a category. Not just the interface, but the implementation as well. It's good to have some distance conceptually between private and non-private methods. I include everything in my .m file. Put background thread methods in a category. Same as above. I've found it's good to keep a clear conceptual barrier when you're thinking about what's on the main thread and what's not. Use #pragma mark [section]. Usually I group by my own methods, each subclass's overrides, and any information or formal protocols. This makes it a lot easier to jump to exactly what I'm looking for. On the same topic, group similar methods (like a table view's delegate methods) together, don't just stick them anywhere. Prefix private methods & ivars with _. I like the way it looks, and I'm less likely to use an ivar when I mean a property by accident. Don't use mutator methods / properties in init & dealloc. I've never had anything bad happen because of it, but I can see the logic if you change the method to do something that depends on the state of your object. Put IBOutlets in properties. I actually just read this one here, but I'm going to start doing it. Regardless of any memory benefits, it seems better stylistically (at least to me). Avoid writing code you don't absolutely need. This really covers a lot of things, like making ivars when a #define will do, or caching an array instead of sorting it each time the data is needed. There's a lot I could say about this, but the bottom line is don't write code until you need it, or the profiler tells you to. It makes things a lot easier to maintain in the long run. Finish what you start. Having a lot of half-finished, buggy code is the fastest way to kill a project dead. If you need a stub method that's fine, just indicate it by putting NSLog( @"stub" ) inside, or however you want to keep track of things.

简单但经常被遗忘。根据规格:

一般来说，方法各不相同 具有相同选择器的类 (相同的名字)也必须共享 相同的返回值和参数类型。这 约束是由编译器施加的 允许动态绑定。

在这种情况下，所有相同的命名选择器，即使在不同的类中，也会被认为具有相同的返回/参数类型。这里有一个简单的例子。

@interface FooInt:NSObject{}
-(int) print;
@end

@implementation FooInt
-(int) print{
    return 5;
}
@end

@interface FooFloat:NSObject{}
-(float) print;
@end

@implementation FooFloat
-(float) print{
    return 3.3;
}
@end

int main (int argc, const char * argv[]) {

    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];    
    id f1=[[FooFloat alloc]init];
    //prints 0, runtime considers [f1 print] to return int, as f1's type is "id" and FooInt precedes FooBar
    NSLog(@"%f",[f1 print]);

    FooFloat* f2=[[FooFloat alloc]init];
    //prints 3.3 expectedly as the static type is FooFloat
    NSLog(@"%f",[f2 print]);

    [f1 release];
    [f2 release]
    [pool drain];

    return 0;
}   

对于初学者来说，一个很明显的方法是:利用Xcode的自动缩进功能。即使是从其他源复制/粘贴代码，粘贴完代码后，也可以选择整个代码块，右键单击它，然后选择选项重新缩进该代码块中的所有内容。

Xcode会解析这个section并根据括号，循环等缩进它。这比每一行都按空格键或tab键要有效率得多。

只释放dealloc方法中的属性。如果你想释放属性所持有的内存，只需将其设置为nil:

self.<property> = nil;

在dealloc中清理。

这是最容易忘记的事情之一——尤其是在以150英里/小时的速度编码时。总是，总是，总是清理dealloc中的属性/成员变量。

我喜欢使用Objc 2属性-新的点表示法-所以这使得清理变得无痛。通常很简单:

- (void)dealloc
{
    self.someAttribute = NULL;
    [super dealloc];
}

这将为您处理发布，并将属性设置为NULL(我认为这是防御性编程——以防dealloc中的另一个方法再次访问成员变量——很少，但也可能发生)。

在10.5中打开GC后，就不再需要这么多了——但是你可能仍然需要清理你创建的其他资源，你可以在finalize方法中做这件事。