iOS:__弱vs(弱) [英] iOS: __weak vs (weak)

问题描述

这两行代码之间有区别吗?

Are there a differences between these two lines of code?

__weak IBOutlet UITextField *usernameField;

@property (weak) IBOutlet UITextField *usernameField;

如果您在.h或.m文件的接口部分中声明了这两者之一怎么办?

What if you declare either of these in interface section of the .h or the .m files?

推荐答案

是.第一个示例声明一个名为usernameField的弱实例变量，但是第二个示例声明一个名为usernameField的弱属性，并声明一个由属性访问的名为_usernameField的实例变量.

Yes. The first example declares a weak instance variable called usernameField, but the second declares a weak property called usernameField, and an instance variable called _usernameField that is accessed by the property.

如果在.m文件的@interface节中声明它，则只能在该.m文件中访问它(除非您与Objective-C运行时混淆).

If you declare it in an @interface section of the .m file, then it can only be accessed in that .m file (unless you mess with the Objective-C runtime).

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