UIViewController视图控制器在iOS研发中不可或缺，基本上每一个页都的研发都会使用到。

在使用过程中，主要使用了以下几个方面。

1、视图控制器的属性设置。如背景颜色，适配，视图控制器数组属性等

2、视图控制器的生命周期的控制

3、视图控制器间的转场present，或push，以及相对应的dismiss，或pop

……

// MARK: - 适配
func autoSize()
{
        if self.respondsToSelector(Selector("edgesForExtendedLayout"))
        {
            self.edgesForExtendedLayout = UIRectEdge.None
        }
        
        if self.respondsToSelector(Selector("extendedLayoutIncludesOpaqueBars"))
        {
            self.extendedLayoutIncludesOpaqueBars = false
        }
        
        if self.respondsToSelector(Selector("automaticallyAdjustsScrollViewInsets"))
        {
            self.automaticallyAdjustsScrollViewInsets = false
        }
}

// MARK: - 根视图控制器
var isRootViewController:Bool
{
        get
        {
            if self.navigationController!.viewControllers.first!.isEqual(self)
            {
                return true
            }
            
            return false
        }
}

 // MARK: - 视图控制器索引下标值
var indexViewController:Int
{
        get
        {
            let indexVC = self.navigationController!.viewControllers.indexOf(self)!
            return indexVC
        }
}

// MARK: - 返回上层视图控制器
func backPrevIoUsController()
{
        if self.isRootViewController
        {
            self.dismissViewControllerAnimated(true,completion: nil)
        }
        else
        {
            if (self.presentedViewController != nil)
            {
                self.dismissViewControllerAnimated(true,completion: nil)
            }
            else
            {
                self.navigationController!.popViewControllerAnimated(true)
            }
        }
}

override func loadView() {
        
        super.loadView()
        
        // 视图控制器背景颜色
        self.view.backgroundColor = UIColor.whiteColor()
}

// present视图控制器
let nextVC = PresentViewController()
let nextNav = UINavigationController(rootViewController: nextVC)
/*
视图控制器翻转效果
由下向上推出（默认模式） CoverVertical
水平翻转 FlipHorizontal
淡入淡出 CrossDissolve
翻页效果 PartialCurl
        
注意：如果有导航视图控制器时，翻转效果设置在导航视图控制器；没有时则设置在视图控制器。
*/
nextNav.modalTransitionStyle = UIModalTransitionStyle.PartialCurl
        
self.presentViewController(nextNav,animated: true,completion: nil)

// 返回上一个视图控制器
self.dismissViewControllerAnimated(true,completion: nil)

// push视图控制器
let nextVC = PopViewController()
// self.navigationController!.pushViewController(nextVC,animated: true)
        
// 转场动画1
UIView.beginAnimations(nil,context: nil)
UIView.setAnimationCurve(UIViewAnimationCurve.EaseInOut)
UIView.setAnimationDuration(0.6)
self.navigationController!.pushViewController(nextVC,animated: true)
UIView.setAnimationTransition(UIViewAnimationTransition.CurlUp,forView: self.navigationController!.view,cache: false)
UIView.commitAnimations()

// 转场动画2
let animation = CATransition()
animation.duration = 0.6
animation.type = kCATransitionReveal
animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaSEOut)
animation.subtype = kCATransitionFromBottom
self.navigationController!.pushViewController(nextVC,animated: true)
self.navigationController!.view.layer.addAnimation(animation,forKey: nil)

// 返回上一个视图控制器
self.navigationController!.popViewControllerAnimated(true)
// 返回根视图控制器
self.navigationController!.popToRootViewControllerAnimated(true)
// 返回指定视图控制器
let indexVC = self.navigationController!.viewControllers[2]
self.navigationController!.popToViewController(indexVC,animated: true)