iOS 关闭UITabBarController双击返回根控制器

<UITabBarControllerDelegate>

//接受tabbar代理方法

self.delegate =self;

// 调用代理方法

- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController{

   UIViewController *vcSelected = tabBarController.selectedViewController;

    if ([vcSelectedisEqual:viewController]) {

        returnNO;

    }

    return YES;

}