是否会自动发布相关对象？ [英] Will An Associated Object Be Released Automatically?

问题描述

注意：这个其他问题似乎相关但不是：关联对象什么时候发布？

Note: This other question seems relevant but it's not: When does an associated object get released?

我正在向 UIView 实例添加第二个描述，如下所示：

I'm adding a second description to a UIView instance as follows:

- (void) setSecondDescription:(UIView*)view description2:(NSString*)description2 {
    objc_setAssociatedObject (view,&key,description2,OBJC_ASSOCIATION_RETAIN);
}

- (NSString*) secondDescription:(UIView*)view {
    return (id)objc_getAssociatedObject(view, &key);   
}

如果 UIView deallocs，相关描述2是否会被解除分配？有没有办法让这种情况自动发生？

If the UIView deallocs, will the associated description 2 get dealloced? Is there any way to get this to happen automatically?

推荐答案

如果你想实际看有关整个dealloc时间表的描述，请参阅WWDC 2011，Session 322,36：22。但是，这是基本的纲要（我想记住它，所以这是我的代码中的实际注释）。

If you want to actually see the description of the entire dealloc timeline, look at WWDC 2011, Session 322, 36:22. However, here's the basic rundown (I wanted to remember it, so this is an actual comment in a piece of my code).

注意，关联的对象被释放在生命周期结束时。

Note, that the associated objects are released at the end of the life cycle.

// General Information
// We take advantage of the documented Deallocation Timeline (WWDC 2011, Session 322, 36:22).
// 1. -release to zero
//     * Object is now deallocating and will die.
//     * New __weak references are not allowed, and will get nil.
//     * [self dealloc] is called
// 2. Subclass -dealloc
//     * bottom-most subclass -dealloc is called
//     * Non-ARC code manually releases iVars
//     * Walk the super-class chain calling -dealloc
// 3. NSObject -dealloc
//     * Simply calls the ObjC runtime object_dispose()
// 4. object_dispose()
//     * Call destructors for C++ iVars
//     * Call -release for ARC iVars
//     * Erase associated references
//     * Erase __weak references
//     * Call free()

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