iOS 一个类中申明一个UIButton* butto 属性用strong 和用属性weak区别

Question

假设有一个类 名字叫做Puzzled继承UIViewController
声明了个属性 @property (nonatomic, strong) UIButton *btn;

跟声明了属性 @property (nonatomic, weak) UIButton *btn;
在- (void)viewDidLoad方法中调用 {
UIButton *btn = [[UIButton alloc]init];
self.btn = btn
}的区别是什么

Answer 1

Since the generated button has no reference elsewhere, the property of the weak attribute will be lost after you assign the value.

Answer 2

If there are other objects referencing it, use weak, otherwise use strong

If no object refers to it and it is created out of scope, it will be removed

Also, when dragging objects from xib or storyboard, then use weak at this time,