Segway

Segway is an open source implementation of iOS' segues.

Segway is a library that lets you perform and unwind segues programmatically (like with UIKit), but it also allows you to define the segues programmatically. Moreover, it allows you to perform segues without any storyboard, by loading view controllers directly from a class and/or a Nib. Finally, Segway let you attach user info to your segues, for when the sender isn't enough.

Whether you simply like the perform/prepare segue pattern; or you want to slowly get rid of that storyboard in a project you inherited, Segway gives you more flexibility in using segues programmatically.

Install

Install with CocoaPods

Add a pod entry to your Podfile:

pod 'Segway', '~> 0.0.1'

Install the pod(s) by running:

pod install

Install with static libary

Copy the Segway project file in your project and link your target with the static library.

Install manually

1. clone this repository
2. import files under the Segway directory in your project
3. disable arc with -fno-objc-arc for UIPopoverController+SelfRetained.m
4. set OTHER_LINKER_FLAGS="-ObjC" for your target

Usage

First import segway:

#import "Segway.h"

Defining a segue programmatically

To define a segue is a two steps process:

1. Define a template, that will be responsible of creating the segue when performSegueWithIdentifier:sender: is called
2. Register the template with a view controller

Templates can either point to a view controller in a storyboard, by specifying its storyboard ID:

ACStoryboardSegueTemplate *template = [[ACStoryboardPushSegueTemplate alloc] initWithIdentifier:@"push" destinationViewControllerIdentifier:@"myViewControllerIdentifier"];

or to a view controller class and Nib:

ACStoryboardSegueTemplate *template = [[ACStoryboardPushSegueTemplate alloc] initWithIdentifier:@"push" destinationViewControllerClassName:@"MyViewController" withNibName:@"MyViewController" bundle:nil];

Available segues are:

• ACStoryboardPushSegueTemplate
• ACStoryboardModalSegueTemplate
• ACStoryboardPopoverSegueTemplate
• ACStoryboardEmbedSegueTemplate
• ACStoryboardUnwindSegueTemplate

Some templates take additional parameters (e.g. presentation options for modal segue), check the documentation for details.

Note that it is recommended to initialize the templates in the viewDidLoad method (or loadView) as they may depend on some of the controller's views.

Then attach it to the view controller:

[self registerSegueTemplate:template];

Performing a segue

This is the same as UIKit's segues:

[self performSegueWithIdentifier:@"push" sender:self];

If you want to pass extra information, you can use the user info:

[self performSegueWithIdentifier:@"push" sender:self userInfo:@{@"indexPath": indexPath}];

You can then implement prepareForSegue:sender:userInfo: to access the user info:

- (void)prepareForSegue:(ACStoryboardSegue*)segue sender:(id)sender userInfo:(NSDictionary *)userInfo {
    ...
}

Or, because prepareForSegue:sender: still works, you can use it as well, and access userInfo from the segue:

- (void)prepareForSegue:(UIStoryboardSegue*)segue sender:(id)sender {
	NSDictionary *userInfo = segue.userInfo;
	...
}

Note: userInfo only works for ACStoryboardSegues and unwinding UIStoryboardSegue.

Unwinding

Like for regular segues, register a template first. The action argument is a string with the name of the selector to unwind to:

[self registerSegueTemplate:[[ACStoryboardUnwindSegueTemplate alloc] initWithIdentifier:@"unwind" action:@"unwindAction:"]];

You can then unwind with perform:

[self performSegueWithIdentifier:@"unwind" sender:self];

Like UIkit, it will try to unwind to the first view controller that implements a method named like the one you passed as the action argument:

- (IBAction)unwindAction:(id)sender {
	...
}

Note that, like UIKit, prepareForSegue:identifier: is not called before unwinding.

Mixing UIkit and Segway segues

When using Segway, UIkit's segues are still working. Segway will not impact the segues defined in a storyboard:

• segues defined in a storyboard can still be performed by the storyboard
• segues defined in a storyboard can still be performed programmatically

Subclassing

Like in UIKit, you can subclass ACStoryboardSegue to make your own segues.

If you segue subclass does not take any argument besides the usual identifier, source and destination, you can simply use the generic ACStoryboardSegueTemplate and set its segueClassName property:

ACStoryboardSegueTemplate *segueTemplate = [[ACStoryboardSegueTemplate alloc] initWithIdentifier:@"segueIdentifier" destinationViewControllerIdentifier:@"viewControllerB"];
segueTemplate.segueClassName = @"MyStoryboardSegueSubclass";

If you need to give more parameters to the segue, you may need to subclass a ACStoryboardSegueTemplate.

Documentation

If you have appledoc installed, you can generate the documentation by running the corresponding target.

Demo

Two demo apps are available:

• SegwayDemo let you try every Segway's segues
• SegwayDemoWithoutStoryboard let you push a simple view controller and works without any storyboard at all

Bugs and limitations

Given the complexity of reverse-engineering UIKit and its numerous of (subtle) private functions, there are some aspects that weren't implemented or aren't working correctly:

• unwinding from popover does not work.
• no support for the iPad's split view controller, more specifically:
  • the replace segue is not implemented.
  • performing any other segue in a split view controller is not implemented.
• storyboards cannot perform segues defined programmatically with Segway. You need to call them programmatically.
• user info is only for programmatically-defined ACStoryboardSegues.