[小技巧]自定義navigation item 返回按鈕圖示

//讓返回沒有文字顯示

self.navigationItem.backBarButtonItem = UIBarButtonItem(title: "", style: .Plain, target: nil, action: nil)

     
//設置返回按鈕圖示

self.navigationController!.navigationBar.backIndicatorImage = UIImage(named:"icon_page.png")!

       self.navigationController!.navigationBar.backIndicatorTransitionMaskImage = UIImage(named:"icon_page.png")!

//另外可以改顏色

 var nav = self.navigationController?.navigationBar

        

        nav?.barStyle = UIBarStyle.Black

        nav?.tintColor = UIColor.greenColor()

//如要改特定顏色,可以查詢色碼,上述的barStyle那一行變成

nav?.barTintColor = UIColor(red:0.24, green:0.23, blue:0.22, alpha:1.0)