自定义使用segueWithIdentifier UIStoryboardSegue:来源:目的地:performHandler:

I am trying to use a custom UIStoryboardSegue to implement a transition between two view controllers. I can do this by subclassing UIStoryboardSegue, and then setting this class in IB. However, I was looking at the docs which say:

我尝试使用自定义的UIStoryboardSegue来实现两个视图控制器之间的转换。我可以通过子类化UIStoryboardSegue，然后在IB中设置这个类来实现。

If your segue does not need to store additional information or provide anything other than a perform method, consider using the segueWithIdentifier:source:destination:performHandler: method instead.

如果您的segue不需要存储额外的信息或提供除执行方法以外的其他信息，那么可以考虑使用segueWithIdentifier:源:destination:performHandler:方法。

Implying that you don't need to create the custom subclass, just use the custom performHandler.

这意味着您不需要创建自定义子类，只需使用自定义performHandler。

I am confused as to where this code should go, and how I go about using it. Do I create the segue as normal in IB and then override that before it is fired (maybe in shouldPerformSegue: or similar). Elsewhere in apple's documentation it says:

我不知道这段代码应该放在哪里，以及如何使用它。在IB中，我是否像往常一样创建segue，然后在它被触发之前重写它(可能在shouldPerformSegue:或类似)?在苹果的其他文件中，它写道:

Your app never creates segue objects directly; they are always created on your behalf by iOS when a segue is triggered

你的应用程序从不直接创建segue对象;当触发segue时，iOS总是代表你创建它们

So I don't quite understand why they are then saying to instantiate a segue using a class creator method.

所以我不太明白他们为什么要用class creator方法实例化segue。

1 个解决方案

#1

The point of segueWithIdentifier:source:destination:performHandler:

的segueWithIdentifier:来源:目的地:performHandler:

Provide an alternative to UIViewController performSegueWithIdentifier:sender in cases where you also want to create a custom transition, without creating a segue subclass.
提供一个UIViewController performSegueWithIdentifier的替代方法:sender，在这种情况下，您还需要创建自定义转换，而无需创建segue子类。
Vend a segue that can be used as the return for segueForUnwindingToViewController:fromViewController:identifier
Vend:一个可作为segueforunwindtoviewcontroller:fromViewController:identifier的返回的segue

As noted above, this approach is only viable for segues which you would call manually -- i.e. not for segues that would otherwise be triggered via IB triggers.

如上所述，此方法仅适用于您将手动调用的segue——也就是说，不适用于通过IB触发器触发的segue。

So, for example, if you have a segue that needs to be triggered after a certain timeout period (such as a custom lock-screen), you could use segueWithIdentifier:source:destination:performHandler: to handle the custom transition.

因此，例如，如果您有一个需要在某个超时期间(如自定义锁屏)后触发的segue，您可以使用segueWithIdentifier:source:destination:performHandler:来处理自定义转换。

-(void)appTimeoutLockScreen
{
    UIStoryboardSegue *segue = 
                [UIStoryboardSegue segueWithIdentifier:@"LockScreenSegue" 
                                                source:sourceVC 
                                           destination:destinationVC 
                                        performHandler:^{
                     // transition code that would 
                     // normally go in the perform method
                }];
    // Dev is responsible for calling prepareForSegue and perform.
    // Note, the order of calls for an IB triggered segue as well as
    // a performSegueWithIdentifier segue is perform first, then
    // prepareForSegue:sender. Manual segues need to inverse the call
    // in order to ensure VC setup is finished before transition.
    [self prepareForSegue:segue sender:self];
    [segue perform];
}

Another practical use for the method is unwinding segues. Using a similar scenario to the previous example, we could use it to return a segue to transition from a lock screen back to the previous viewController:

该方法的另一个实际应用是展开segue。使用与前一个示例类似的场景，我们可以使用它返回一个segue，以从锁屏幕转换回前一个viewController:

-(UIStoryboardSegue *)segueForUnwindingToViewController:(UIViewController*)toVC 
                                     fromViewController:(UIViewController *)fmVC
                                             identifier:(NSString *)identifier
{
    UIStoryboardSegue *segue = 
            [UIStoryboardSegue segueWithIdentifier:@"FromLockScreenSegue" 
                                            source:fmVC
                                       destination:toVC 
                                    performHandler:^{
                // transition code
            }];

    return segue;
}

#1