Swift3.0之hidesBottomBarWhenPushed的使用和注意事项

我们有时候在开发iOS的时候，涉及到跳转界面时，需要隐藏tabbar，以便我们重新定义新的。

OC版本的：

//1.设置self.tabBarController.tabBar.hidden=YES;
     
self.tabBarController.tabBar.hidden=YES;
 
//2.如果在push跳转时需要隐藏tabBar，设置self.hidesBottomBarWhenPushed=YES;
 
    self.hidesBottomBarWhenPushed=YES;
    NextViewController *next=[[NextViewController alloc]init];
    [self.navigationController pushViewController:next animated:YES];
    self.hidesBottomBarWhenPushed=NO;

//注意：在push后设置self.hidesBottomBarWhenPushed=NO;

其实在OC中直接对 next.hidesBottomBarWhenPushed=YES就可以在跳转界面的时候隐藏tabbar

而不需要设置self.hidesBottomBarWhenPushed=NO;

Swift版本的：

let  testVC = UIViewController()self.hidesBottomBarWhenPushed = trueself.navigationController?.pushViewController(testVC, animated: true)self.hidesBottomBarWhenPushed = false

如果是push到下个界面就没有问题，如果从第二个界面push到第三个界面，再返回第二个界面，tabbar就会显示，这样还是达不到我们想要的结果

下面是我自己对hidesBottomBarWhenPushed 属性设置的一个总结，应该每一次push，都去执行对hidesBottomBarWhenPushed属性进行设置，如

果要push的界面多了，那不是做很多繁琐的工作，所以自定义了UINavigationController，对hidesBottomBarWhenPushed属性进行统一设置

import UIKitclass BaseNavigationController: UINavigationController {    override func viewDidLoad() {        super.viewDidLoad()        // Do any additional setup after loading the view.    }    override func didReceiveMemoryWarning() {        super.didReceiveMemoryWarning()        // Dispose of any resources that can be recreated.    }        //每一次push都会执行这个方法，push之前设置viewController的hidesBottomBarWhenPushed    override func pushViewController(_ viewController: UIViewController, animated: Bool) {        viewController.hidesBottomBarWhenPushed = true        super.pushViewController(viewController, animated: true)        viewController.hidesBottomBarWhenPushed = false           }        override func popViewController(animated: Bool) -> UIViewController? {                //以下函数是对返回上一级界面之前的设置操作        //每一次对viewController进行push的时候，会把viewController放入一个栈中        //每一次对viewController进行pop的时候，会把viewController从栈中移除        if self.childViewControllers.count == 2        {            //如果viewController栈中存在的ViewController的个数为两个，再返回上一级界面就是根界面了            //那么要对tabbar进行显示            let controller:UIViewController = self.childViewControllers[0]            controller.hidesBottomBarWhenPushed = false                    }        else        {            //如果viewController栈中存在的ViewController的个数超过两个，对要返回到的上一级的界面设置hidesBottomBarWhenPushed = true            //把tabbar进行隐藏            let count = self.childViewControllers.count-2            let controller = self.childViewControllers[count]            controller.hidesBottomBarWhenPushed = true        }                        return super.popViewController(animated: true)    }}