ios 在关闭前一个视图控制器后立即呈现视图控制器 [英] ios present view controller immediately after dismissing a previous one

问题描述

在我的 ios 应用程序中，假设我有三个 ViewController:A、B 和 C.

In my ios app lets say I have three ViewControllers: A, B, and C.

从 A 我提出 B 并指定 A 作为代表.在 B 上完成操作后，我想关闭 B 并从 A 呈现 C.但是，我想在屏幕上根本不显示 A 的情况下执行此操作.这是我现在的代码，在 A 类中:

From A I present B and assign A as a delegate. After an action is done on B I want to then dismiss B and present C from A. However, I want to do this without A showing up on the screen at all. This is my code right now, inside class A:

-(void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];

    B *vc = [self.storyboard instantiateViewControllerWithIdentifier:@"B-identifier"];
    vc.delegate = self;
    [self presentViewController:vc animated:NO completion:^{}];

}

然后这是A内部的委托函数，B在执行动作时调用:

Then this is the delegate function inside A that B calls when the action is performed:

- (void) actionPerformed
{
    [self dismissViewControllerAnimated:YES completion:^{
    C *vc = [self.storyboard instantiateViewControllerWithIdentifier:@"C"];
    [self presentViewController:vc animated:NO completion:nil];
}];

然而，这会导致 C 出现一点(在调用解雇之后)，即使我将呈现代码放在解雇的完成处理程序中.我该怎么做才能避免这种情况?

However this causes C to show up for a bit (after calling dismiss) even though I put the presenting code in the completion handler of the dismissal. What can I do to avoid that?

推荐答案

如果您将其用于登录方法，那么您应该尝试不同的方法.我的意思是如果 A 是您的 rootViewController(使其成为登录视图控制器)，它会检查用户是否有会话.假设用户有一个会话，然后使用 [[[[UIApplication sharedApplication] delegate] window]setRootViewController:] 将您的 C viewController 设为 rootViewController，如果他没有会话，则向他显示相同的页面(A viewController) 不需要 B.尝试一下可能会提高您的应用性能.

If you are using it for login approach then you should try a different approach. I mean if A is your rootViewController(make it as login view controller) which check if user has a session or not. suppose user has a session then make your C viewController as rootViewController using [[[[UIApplication sharedApplication] delegate] window]setRootViewController:] and if he does not has a session show him the same page (A viewController) there is no need of B. Just try it may be it will improve your app performance.

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