Swift

I am a big fan of automation in software development so when I started doing iOS development one of my goals was to automate everything on the iOS project.

No more manual versioning, manual build distribution… let the computers do the work for me. Here is the setup I ended up with.

Separate app ids for development and distribution

Let’s say your app id is com.company.app. You can use that app id when developing the app, running it in the simulator or on your device and also when distribution the app using services like TestFlight or uploading it to the AppStore.

With just one app id you cannot have both the AppStore version and a development version installed on your device. This a problem when working on an app that you use daily for communication with your colleagues, but you are working on a feature that requires you to use a different server, or some MDM, etc.

There is also another problem you will encounter if you use push notifications. When you create a push notification certificate for production, push notifications for your app will work with AppStore builds, with ad-hoc builds in TestFlight and other services but you will not get any notifications when running the app on your device deployed from Xcode. At least not easily.

To counter that, I use separate app ids

• com.company.app with push notifications set to production for AppStore and ad-hoc distribution
• com.company.app.dev with push notifications set to sandbox for development

This of course requires your backend to support it by choosing the right push notifications certificate depending on the app id.

With this setup, I can

• use the AppStore version and the development version of the app on my device at the same time
• have push notifications working also in the development version of the app

Automatic builds and tests with Gitlab

The iOS project I work on uses self-hosted Gitlab instance, so using Gitlab CI was the obvious choice. You just need a machine with macOS that is always online, install the Gitlab runner, connect it to the Gitlab instance and you are done. Everything else is just a matter of configuration in a file in your repository.

Working on an iOS or macOS project in Xcode you typically create classes with the same structure over and over again.

I use coordinators so I am creating new UIViewControllers, each time referencing RxSwift, having methods for setting up UI, bindings .. most of the time also containing a delegate for the coordinator.

Having to create files with the same structure over and over again manually is a waste of time, a much better solution is creating Xcode file templates for those files.

Xcode file templates

File template location

All the Xcode custom file templates are located in ~/Library/Developer/Xcode/Templates/File Templates and grouped into sections by their folder name. If you want Xcode to show a “Custom” section at the bottom of the new file dialog, just create a ~/Library/Developer/Xcode/Templates/File Templates/Custom folder.

File template structure

Each file template is a separate folder with a name ending in .xctemplate. If you want to create a simple “Swift Class” file template, you have to create a folder named Swift Class.xctemplate in ~/Library/Developer/Xcode/Templates/File Templates/Custom.

Each file template folder should contain at least 3 files:

• TemplateInfo.plist - describing the template
• TemplateIcon.png - icon shown in the Xcode new file dialog
• ___FILEBASENAME___.swift - the actual template file

When developing any application it is a good practice not to hard-code your strings but to use some kind of a strings file. In iOS you typically use the standard Localizable.strings file as storage and some string based API to use those strings, like

extension String {
    var localized: String {
        return NSLocalizedString(self, tableName: nil, bundle: Bundle.main, value: "", comment: "")
    }
}

This of course works but it is not exactly “safe”, if you make a typo the compiler has no way to warn you and you, or worse your customers, will find out at runtime. There is a better way.

SwiftGen is a Swift code generator that will help you with that. It can generate enums for your strings, assets, storyboards. With a simple configuration SwiftGen reads your Localizable.strings file and generates a L10n enum with all the strings

internal enum L10n {

  /// Search colleagues by name or surname
  internal static let enterpriseDirectorySearchInfo = L10n.tr("Localizable", "enterprise_directory_search_info")
   /// Copyright © Igor Kulman\nAll rights reserved.\n\nVersion %@
  internal static func welcometxt(_ p1: String) -> String {
    return L10n.tr("Localizable", "welcometxt", p1)
  }
  ...
}

Simple strings are generated as properties and strings with formatting parameters as functions, so you always known how many parameters to use. It also makes it easier to find the correct string by showing the strings in Xcode intellisense

If you want a more complete example, take a look at my iOS sample app on Github

The iOS 11 has many bugs, more are introduced with every update. I only just recently discovered a bug in the registration part of the application I work on.

The registration flow contains a few screens to gather the user data. The navigation among those screens (managed by a coordinator) is done by Back and Next buttons in the UINavigationBar. The users can at any time get back to the previous screen, and if they are running iOS 11.2 they will see the bug:

The users tap the Next button to go to the next screen and when they get back, the Next button is faded. It works, can be tapped, but does not look right. This only happens on iOS 11.2.

When you have an iOS application running in production, you probably want to know if and why it crashes, so you can fix all your bugs as soon as possible.

There are many good services like HockeyApp that can help you with that, but sometimes you are not allowed to use any 3rd party service for this. In this case you have to look for another solution how to get info about all your iOS application crashes and process it by yourself.

PLCrashReporter

Looking for a crash reporting solution I found PLCrashReporter. This library seems to be kind of a standard for crash reporting, used by the already mentioned HockeyApp and many others.

It is a Objective-C framework with latest version from 2014, but it still works and you can use it in your Swift application.

Installation

After downloading the latest PLCrashReporter and adding it to your project as a linked framework, you need to import it in bridging header

#import <CrashReporter/CrashReporter.h>

Usage

In the application I currently work on I use CleanroomLogger for all the logging, giving the user the ability to export all the logs and send them using the standard iOS share.