循环引用

• 建立 NetworkTools 对象

  /// 完成回调属性
    var finishedCallBack: (()->())?
    
    /// 加载数据
    ///
    /// - parameter finished: 完成回调
    func loadData(finished: () -> ()) {
        
        self.finishedCallBack = finished
        
        print("开始加载数据...")
        
        // ...
        working()
    }
    
    func working() {
        finishedCallBack?()
    }
    
    deinit {
        print("网络工具 88")
    }

• 实例化 NetworkTools 并且加载数据

  class ViewController: UIViewController {
        
        var tools: NetworkTools?
        
        override func viewDidLoad() {
            super.viewDidLoad()
            
            tools = NetworkTools()
            tools?.loadData() {
                print("come here \(self.view)")
            }
        }
        
        /// 与 OC 中的 dealloc 类似，注意此函数没有()
        deinit {
            print("控制器 88")
        }
    }

• 循环链：self(ViewController) -> tools(NetworkTools) ->finishedCallBack -> finished -> self(ViewController)

解决办法

• Swift

 loadData { [weak self] in
            print("\(self?.view)")
        }

• OC
  __weak typeof(self) weakSelf