我知道HIG(这非常方便!),但是在编写Objective-C时,更具体地说,在使用Cocoa(或CocoaTouch)时,您使用了什么编程实践?
当前回答
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。
其他回答
不要把Objective-C写成Java/ c# / c++等。
我曾经看到一个编写Java EE web应用程序的团队尝试编写Cocoa桌面应用程序。就好像它是一个Java EE web应用程序。有很多AbstractFooFactory、FooFactory、IFoo和Foo,而他们真正需要的只是一个Foo类,可能还有一个Fooable协议。
确保你不这样做的部分原因是真正理解语言的差异。例如,您不需要上面的抽象工厂和工厂类,因为Objective-C类方法和实例方法一样是动态分派的,并且可以在子类中重写。
@kendell
而不是:
@interface MyClass (private)
- (void) someMethod
- (void) someOtherMethod
@end
Use:
@interface MyClass ()
- (void) someMethod
- (void) someOtherMethod
@end
Objective-C 2.0新功能。
Apple的Objective-C 2.0参考中描述了类扩展。
类扩展允许你在主类@interface块之外的位置为类声明额外的必需API
所以它们是实际类的一部分——而不是类之外的(私有)类别。细微但重要的区别。
黄金法则:如果你分配了,那么你就释放了!
更新:除非你正在使用ARC
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;
}
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.
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