For starters, some of you may be wondering why you should use two builds while developing your app. The reason is because as you continue to build new features, you want to separate the development version from the existing public production app. Standard software development practice is to use different environments for the different versions of the software. The development version of an app typically uses a different database and server from the production environment. Developers commonly use dummy images or data during testing. In testing or development environments, it’s not uncommon for one to use test data such as “test comment”, “argharghargh” and “one more test comment”. Obviously, you don’t want your real users to see this kind of messages. In the case, if your app using an analytics system, you may even send thousands of events during the testing stage. Again, you don’t want to mix the test data with the production data in the same database. This is why it’s always recommended to separate the development and production builds.

While using two separate environments, your app needs to have a way to find out which environment it should connect to. One popular method is to define a global variable in your main app delegate, which will initialize your app to development or production mode.

In this article I will show you a better approach to differentiate between the development and production builds. Specifically, we will create a development target in XCode. This method is suitable for both new and existing large projects, so you can use one of your existing apps to follow along in this tutorial.

By applying this approach, the production and development versions of the app will have the same base code, but can have different icons, bundle IDs and point to separate databases. The distribution and submission processes will be very straightforward. Most importantly, your testers and managers will be able to install both versions of the app on the same device, so they fully understand which version they’re trying out.

How to Create a New Target

So how can you create a development target in Xcode? I will walk you through the procedure step-by-step with my template project “todo”. You can use your own project and follow the procedures:

1. Go to project’s settings in the Project Navigator panel. Under the Targets sections, right click the existing target and select Duplicate to copy your existing target.

2. Xcode will ask you if your new target is for iPad development. For this tutorial, we just select “Duplicate Only”.

3. Now that we have a new target and a new build scheme with the name todo copy. Let’s rename it so it is easier to understand.

• Select the new target in the TARGETS list. Press Enter to edit the text and put a more appropriate name. I prefer “todo Dev”. You’re free to choose whatever name you like.
• Next, go to “Manage Schemes…”, select the new scheme you created in step 1 and press “Enter”. Make the scheme name the same as the new target name (which is the one you choose for the new target.)

4. Steps 4 is optional, but highly recommended. If you want to make it easy and dummy-proof to distinguish between the development and production builds, you should use separate icons and launch screens for each version. This will make it obvious for your testers to know which app they are using, and hopefully prevent you from shipping a development version. 

Go to Assets.xcassets and add a new icon. Right click icon > App Icons & Launch Images > New iOS App Icon. Rename the new icon to “AppIcon-Dev” and add your own images.

5. Now go back to project settings, select your development target and change the bundle identifier. Say, you can simply append “Dev” to the original ID. If you performed step 4, make sure you change the app icon setting to the one created in the previous step.

6. Xcode automatically added a plist file for your target (e.g. todo copy-Info.plist). You can find it at the root folder of your project. Rename it from “copy” to “Dev”, and place it right below your original plist file. Here, it will be easier for you to manage the file.

7. Now open “Build Settings” of your development target, scroll to “Packaging”, and change the value to the development plist file (e.g. todo Dev.plist).

8. Lastly, we’ll configure a preprocessing macro/compiler flag for both production and development targets. So later we can use the flag in our code to detect which version the app is currently running.

For Objective-C projects, go to Build Settings and scroll to Apple LLVM 7.0 - Preprocessing. Expand Preprocessor Macros and add a variable to both Debug and Releasefields. For the development target (i.e. todo Dev), set the value to DEVELOPMENT=1. On the other hand, set the value to DEVELOPMENT=0 to indicate a production version.

For Swift project, the compiler no longer supports preprocessor directives. Instead, it uses compile-time attributes and build configurations. To add a flag to indicate a development build, select the development target. Go to Build Settings and scroll down to the Swift Compiler - Custom Flags section. Set the value to -DDEVELOPMENT to indicate the target as a development build.

Now that you have created and configured the development target, what’s next?

Using the Target and Macro

With the macro DEV_VERSION configured, we can utilize it in the code and perform dynamic compilation for your project. Here is a simple example:

Objective-C:

Swift:

Now when you select the “todo Dev” scheme and run the project, you’ll create the development build automatically with the server configuration set to the development environment. You’re now ready to upload the development build to TestFlight or HockeyApp for your testers and managers to test out.

Later if you need to create a production build, you can simply select the “todo” scheme. No code change is required.

Some Notes on Managing Multiple Targets

1. When you add new files to the project, don’t forget to select both targets to keep your code in sync in both builds.

2. In case you’re using Cocoapods, don’t forget to add the new target to your podfile. You can use link_with to specify multiple targets. You can further consult the Cocoapods documentationfor details. Your podfile should look something like this: