分配给属性的变量是否遵循该属性的行为? [英] Do variables assigned to properties follow the behavior of that property?

问题描述

寻求对链接"到实例变量时 Objective-C 属性如何工作的一些说明.我的困惑源于如何通过 @synthesize 指令将属性设置为等于实例变量，例如...

Looking for a little clarification on how Objective-C properties work when 'linked' to instance variables. My confusion stems from how you can set a property equal to a instance variable through the @synthesize directive, like...

@synthesize someProp = _someIVar;

现在，如果我的 someProp 就像...

Now, if my someProp is all like...

@property (retain,readonly) SomeClass* someProp

...这会...

-(id)initWithAutoreleasedInstanceOfSomeClass:(SomeClass*)thingThatIsAutoreleased {
    self = [super init];
    if(self) {
         _someIVar = thingThatIsAutoreleased;
    }
    return self;
}

... 导致 thingThatIsAutoreleased 被保留?

... cause thingThatIsAutoreleased to be retained?

坦克！

推荐答案

因为它是只读的，所以你不会有一个 setter 但你可以通过设置内部成员变量来设置值.如果你设置了内部var，那么你需要保留它.

since it's readonly you won't have a setter but you can set the value by setting the internal member variable. If you set the internal var, then you need to retain it.

_someIVar = [thingy retain];

请注意，您可以通过 KVC 调用并触发保留

Note that you can call via KVC and get the retain to trigger

[self setValue:myValue forKey:@"someProp"];

所以，回答您最初的问题，不，如果您直接设置 iVar，您将不会获得自动保留/释放.如果您要操作 iVar，则必须保留/释放.

So, to answer your original question, No, you won't get automatic retain/release if you're setting the iVar directly. You have to retain/release if you're manipulating the iVar.

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