         }
     }
     
-    // navigationBar effectView alpha
-    var navBarEffectAlpha:CGFloat {
-        get {
-            guard let effectAlpha = objc_getAssociatedObject(self, &AssociatedKeys.navBarEffectAlpha) as? CGFloat else {
+    // navigationBar _UIBarBackground alpha
+    var navBarBackgroundAlpha:CGFloat {
+        get {
+            guard let barBackgroundAlpha = objc_getAssociatedObject(self, &AssociatedKeys.navBarBackgroundAlpha) as? CGFloat else {
                 return 1.0
             }
-            return effectAlpha
-        }
-        set {
-            objc_setAssociatedObject(self, &AssociatedKeys.navBarEffectAlpha, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
+            return barBackgroundAlpha
+        }
+        set {
+            objc_setAssociatedObject(self, &AssociatedKeys.navBarBackgroundAlpha, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
             
             if customNavBar.isKind(of: UINavigationBar.self) {
                 let navBar = customNavBar as! UINavigationBar

        }
    }
    
    class var defaultEffectAlpha: CGFloat {
        get {
            return 1.0
        }

        toColor.getRed(&toRed, green: &toGreen, blue: &toBlue, alpha: &toAlpha)
        
        // calculate middle color RGBA
        let newRed = fromRed + (toRed - fromRed) * percent
        let newGreen = fromGreen + (toGreen - fromGreen) * percent
        let newBlue = fromBlue + (toBlue - fromBlue) * percent
        let newAlpha = fromAlpha + (toAlpha - fromAlpha) * percent
        return UIColor(red: newRed, green: newGreen, blue: newBlue, alpha: newAlpha)
    }
    
    // Calculate the middle alpha
