添加

• 初始化控制器
• 添加控制器
• 调整添加View
• didMoveToParentViewController通知

-(void)addChildVc:(UIViewController*)vc view:(UIView *)view {
    BOOL needAddToParent = !vc.parentViewController;
    if (needAddToParent) [self addChildViewController:vc];
    vc.view.frame = view.bounds;
    [view addSubview:vc.view];
    if (needAddToParent) [vc didMoveToParentViewController:self];
}

删除

• willMoveToParentViewController通知
• 是否加载View，加载则移除View
• 移除控制器

-(void)removeChildVc:(UIViewController*)vc {
    [vc willMoveToParentViewController:nil];
    if (![vc isViewLoaded]) {
        [vc removeFromParentViewController];
    } else {
        [vc.view removeFromSuperview];
        [vc removeFromParentViewController];
    }
}