     override func didReceiveMemoryWarning() {
         super.didReceiveMemoryWarning()
         // Dispose of any resources that can be recreated.
+    }
+    
+    override func viewWillAppear(animated: Bool) {
+        super.viewWillAppear(animated)
+        
+        self.navigationController?.delegate = self
+    }
+    
+    override func viewWillDisappear(animated: Bool) {
+        super.viewWillDisappear(animated)
+        
+        self.navigationController?.delegate = nil
     }
     
     // MARK: - --------------------功能函数--------------------

    }
    
    // MARK: - --------------------代理方法--------------------
    // MARK: - 代理种类注释
    // MARK: 代理函数注释
    
    // MARK: - --------------------属性相关--------------------
    // MARK: 属性操作函数注释


import UIKit

class BBRootViewController: UIViewController, UINavigationControllerDelegate {
    
    // MARK: - --------------------System--------------------
    
