如何在不显示中间视图的情况下展开多个视图 [英] How to unwind through multiple views without displaying intermediate views

问题描述

假设我们有三个视图控制器：1,2和3.使用故事板，使用展开segue从视图控制器3展开到视图控制器1非常简单。然而，当展开时，在显示视图控制器1之前，视图控制器2可以短暂可见。有没有办法从3到1而不再显示2？

Assume we have three view controllers: 1, 2, and 3. Using the storyboard, it's pretty simple to unwind from view controller 3 to view controller 1 using an unwind segue. However, when unwinding, view controller 2 is briefly visible before view controller 1 is displayed. Is there any way to get from 3 to 1 without displaying 2 again?

查看控制器1：

- (void)viewDidAppear:(BOOL)animated {
  [super viewDidAppear:animated];
  NSLog(@"one did appear");
}

- (IBAction)goToTwo:(id)sender {
  NSLog(@"#### segue to two");
  [self performSegueWithIdentifier:@"TwoSegue" sender:self];
}

- (IBAction)unwindToOne:(UIStoryboardSegue *)sender {
}

查看控制器2：

- (void)viewDidAppear:(BOOL)animated {
  [super viewDidAppear:animated];
  NSLog(@"two did appear");
}
- (IBAction)goToThree:(id)sender {
  NSLog(@"#### segue to three");
  [self performSegueWithIdentifier:@"ThreeSegue" sender:self];
}

查看控制器3：

- (void)viewDidAppear:(BOOL)animated {
  [super viewDidAppear:animated];
  NSLog(@"three did appear");
}

- (IBAction)unwindToOne:(id)sender {
  NSLog(@"#### unwind to one");
  [self performSegueWithIdentifier:@"OneSegue" sender:self];
}

这会产生以下日志消息：

• 一个确实出现


• segue to two


• 两个确实出现


• segue to three


• 三个确实出现


• 放松到一个


• 两个确实出现了


• 一个确实出现了

• one did appear
• segue to two
• two did appear
• segue to three
• three did appear
• unwind to one
• two did appear
• one did appear

我试过使用自定义segues和禁用动画。虽然删除动画会使视图控制器2出现的时间更短，但仍然会出现。有没有办法对此行为进行编程？

I've tried using custom segues and disabling animation. Although removing animation makes view controller 2 appear for an even shorter period of time, it still appears. Is there any way to program this behavior?

故事板的屏幕截图：

推荐答案

Josh的回答让我找到了解决方案。以下是如何完成此任务：

Josh's answer led me to a solution. Here's how to accomplish this:

创建一个根UINavigationController，并将其分配给扩展UINavigationController的类，并覆盖segueForUnwindingToViewController：fromViewController：identifier方法。如果需要，可以通过标识符过滤。

Create a root UINavigationController, and assign it to a class that extends UINavigationController and overrides the segueForUnwindingToViewController:fromViewController:identifier method. This could be filtered by the identifier if desired.

CustomNavigationController：

- (UIStoryboardSegue *)segueForUnwindingToViewController:(UIViewController *)toViewController fromViewController:(UIViewController *)fromViewController identifier:(NSString *)identifier {
  return [[CustomUnwindSegue alloc] initWithIdentifier:identifier source:fromViewController destination:toViewController];
}

创建一个自定义推送segue，其行为类似于模态segue，但利用了我们的导航控制器。用于所有推段。

Create a custom push segue, that behaves like a modal segue, but utilizes our navigation controller. Use this for all "push" segues.

CustomPushSegue：

-(void) perform{
  [[self.sourceViewController navigationController] pushViewController:self.destinationViewController animated:NO];
}

创建自定义展开segue，使用导航控制器弹出到目的地。我们的导航控制器在segueForUnwindingToViewController中调用它：fromViewController：identifier方法。

Create a custom unwind segue, that uses the navigation controller to pop to the destination. This is called by our navigation controller in the segueForUnwindingToViewController:fromViewController:identifier method.

CustomUnwindSegue：

- (void)perform {
  [[self.destinationViewController navigationController] popToViewController:self.destinationViewController animated:NO];
}

通过结合使用这些模式，第二个视图控制器永远不会出现在展开过程。

By utilizing a combination of these patterns, the second view controller never appears during the unwind process.

新日志输出：

• 一个出现


• #### segue to two


• 两个确实出现


• #### segue to three


• 三个确实出现


• ####放松到一个


• 一个确实出现

• one did appear
• #### segue to two
• two did appear
• #### segue to three
• three did appear
• #### unwind to one
• one did appear

我希望这可以帮助其他人解决同样的问题。

I hope this helps someone else with the same issue.

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