iOS5 ARC，IBOutlets 应该定义strong还是weak

有人问，在ARC下，IBOutlets到底应该定义成strong 还是 weak ？支持这个答案的人最多，答案仅是摘自官方文档的一个片段：

From a practical perspective, in iOS and OS X outlets should be defined as declared properties. Outlets should generally be weak, except for those from File’s
Owner to top-level objects in a nib file (or, in iOS, a storyboard scene) which should be strong. Outlets that you create will therefore typically be weak by default, because:

Outlets that you create to, for example, subviews of a view controller’s view or a window controller’s window, are arbitrary references between objects that
do not imply ownership.

The strong outlets are frequently specified by framework classes (for example, UIViewController’s view outlet, or NSWindowController’s window outlet).

@property (weak) IBOutlet MyView *viewContainerSubview;
@property (strong) IBOutlet MyOtherClass *topLevelObject;

 

 

 

大意解释是：

在 ARC
中,一般outlet属性都推荐使用
weak,应该使用 strong
的 outlet
是 File's Owner连接到 nib
的顶层对象。

什么是 File's Owner连接到 nib
的顶层对象呢？

 

说白话一点，就是自定义的view，不是直接作为main view里面一个sub view直接显示出来，而是需要通过实例化创建出来的。你自己实例化，当然需要strong了，不然谁还替你保留对象所有权呢？