.h和.m文件中的@interface定义之间的区别 [英] Difference between @interface definition in .h and .m file

问题描述

通常我们使用

@interface interface_name : parent_class <delegates>
{
......
}
@end 

$ b在.h文件和.m文件中的$ b

方法我们合成了在.h文件中声明的变量的属性。

method in .h file and in .m file we synthesis the properties of variables declared in .h file.

但是在某些代码中，这个@interface ..... @ end方法也保存在.m文件中。这是什么意思？它们之间有什么区别？

But in some code, this @interface.....@end method is kept in the .m file also. What does it mean? What is the difference between them?

还要为.m文件中定义的接口文件提供一些关于getter和setter的话......

Also give some words about getters and setters for the interface file that is defined in .m file...

提前致谢

推荐答案

通常会增加额外的 @ interface 定义包含私有方法的类别：

It's common to put an additional @interface that defines a category containing private methods:

Person.h：

@interface Person
{
    NSString *_name;
}

@property(readwrite, copy) NSString *name;
-(NSString*)makeSmallTalkWith:(Person*)person;
@end

Person.m：

@interface Person () //Not specifying a name for the category makes compiler checks that these methods are implemented.

-(void)startThinkOfWhatToHaveForDinner;
@end


@implementation Person

@synthesize name = _name;

-(NSString*)makeSmallTalkWith:(Person*)person
{
    [self startThinkOfWhatToHaveForDinner];
    return @"How's your day?";
}


-(void)startThinkOfWhatToHaveForDinner
{

}

@end

'私人类别'（无名类别的正确名称不是'私人类别'，它是'类扩展' ）.m阻止编译器警告方法已定义。但是，因为.m文件中的 @interface 是一个类别，所以无法在其中定义ivars。

The 'private category' (the proper name for a nameless category is not 'private category', it's 'class extension') .m prevents the compiler from warning that the methods are defined. However, because the @interface in the .m file is a category you can't define ivars in it.

更新于2012年8月6日：自从这个答案写完以来，Objective-C已经发展：

Update 6th Aug '12: Objective-C has evolved since this answer was written:

• ivars 可以在类扩展中声明（并且总是可以 - 答案是不正确的）


• @synthesize 不是必须


• ivars 现在可以在 @implementation ：



• ivars can be declared in a class extension (and always could be - the answer was incorrect)
• @synthesize is not required
• ivars can now be declared in braces at the top of @implementation:

即

@implementation { 
     id _ivarInImplmentation;
}
//methods
@end

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