         
     }
     
+    override func viewWillAppear(animated: Bool) {
+        super.viewWillAppear(animated)
+        rightButton.hidden = false
+    }
+    
+    override func viewWillDisappear(animated: Bool) {
+        super.viewWillDisappear(animated)
+        rightButton.hidden = true
+    }
+    
     override func tableView(tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
         return 0.1
     }

        return headerView
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let rightButton = UIButton(type: UIButtonType.Custom)
        rightButton.setTitle("设置", forState: UIControlState.Normal)
        rightButton.sizeToFit()
        rightButton.titleLabel?.font = UIFont.systemFontOfSize(15)

        let offsetY = scrollView.contentOffset.y
        
        // 导航栏渐变
        navigationController?.navigationBar.alpha = offsetY / 100
        
        // 下拉放大头部视图
        if offsetY < 0 {
