ios - Detect when my UIView subclass is added to another UIView

Question

I want my UIView subclass to position itself automatically when it is added to a parent container view.

Can I somehow detect when it is added and run my positioning code then or do I need to do something like?

[parentView addSubview:subView];
[setView calcPosition];

Answer 1

UIView provides the methods willMoveToSuperview: and didMoveToSuperview. Just override those to know when the view is added to another view (or later removed).

Answer 2

在子视图中写入方法并从子视图中calcPosition调用它didMoveToSuperview

- (void)didMoveToSuperview
{
    [super didMoveToSuperview];
    [self calcPosition];
}