关于引用计数问题

Question

@interface ViewController ()

@property ( strong , nonatomic ) WeakView * weakView;

@end



    WeakView * view = [[WeakView alloc]init];
    [self.view addSubview:view];
    self.weakView = view;
    NSLog(@"count: --- %ld",CFGetRetainCount((__bridge CFTypeRef)_weakView));
    NSLog(@"count: --- %ld",CFGetRetainCount((__bridge CFTypeRef)self.weakView));

为什么打印是3和4

Answer 1

self.weakView

等效于如下代码：

- (WeakView *)weakView
{
    return [[_weakView retain] autorelease];
}

下个循环回来就回到 3 了

Answer 2

我理解的是 WeakView* + 1，addSubView + 1，然后self.weakView = view是 strong 的再 +1，所以是 3 ……至于为什么是 4 是楼上说的吧~