是否会自动发布相关对象？

Question

注意:这个问题似乎很相关,但事实并非如此:关联对象什么时候发布？

我正在为UIView实例添加第二个描述,如下所示:

- (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);   
}

如果是UIViewdeallocs,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？

Answer 1

如果您想要实际查看整个dealloc时间线的描述,请查看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).

请注意,关联对象在生命周期结束时释放.

// 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()