Setting up Multiple environments in Flutter with Flavors - iOS

I’m using Flutter v3.13.0 for this tutorial.

Setup flavors for iOS

Make sure you enrolled Apple Developer Program to run app on physical devices.

Unfortunately, setting up flavors in iOS is more complex and we’ll have to use XCode and its UI for most of the steps.

Let’s try building our app with a flavor for iOS now to see, what kind of error we get:

flutter build ios --flavor dev

The Xcode project does not define custom schemes. You cannot use the --flavor option.

This means, that on iOS we have to rely on a feature called “custom schemes” to represent our flutter flavors. Setting them up requires multiple steps.

Setup Configurations

Make sure the root Runner node is selected in XCode

In the main window, select the Runner node below PROJECT (NOT below TARGETS)

Select the Info tab

In the Configurations section, do the following:

• Rename Debug to Debug-dev
• Rename Release to Release-dev
• Rename Profile to Profile-dev
• Duplicate Debug-dev and rename it to Debug-uat
• Duplicate Release-dev and rename it to Release-uat
• Duplicate Profile-dev and rename it to Profile-uat
• Duplicate Debug-dev and rename it to Debug-live
• Duplicate Release-dev and rename it to Release-live
• Duplicate Profile-dev and rename it to Profile-live
• This means, for every flavor, we need a separate Debug, Release & Profile configuration.

Assign Build Configurations to Custom Schemes

Now we can set up the actual custom schemes by doing the following:

• Make sure the root Runner node is selected in XCode
• Select Product -> Scheme -> Manage Schemes… in the main toolbar.
• To setup the dev scheme:
  • Select the Runner scheme, click on the settings-icon in the top left and select Duplicate
  • Rename the scheme to dev
  • Make sure Shared is selected
  • Adjust the build configuration to the corresponding -dev version

• Similar to setup the uat and live scheme:
  • Select the Runner scheme again, click on the settings-icon in the top left and select Duplicate
  • Rename the scheme to live
  • For each of the sections (Run, Test, Profile, Analyze, Archive) on the left, change the build configuration to the corresponding -uat and -live version.
  • Make sure Shared is selected
  • Close the dialog

Setup Flavor value per scheme

The Bundle.main.infoDictionary from before refers to the Runner/Info.plist file and App - Flavor is a custom key that we have to add there manually next.

So open the Runner/Info.plist file in XCode and and add a new row with the following settings:

• Key: App - Flavor
• Type: String
• Value: $(APP_FLAVOR)

We now have the key but we still don’t have the actual flavor-specific values per scheme. To add them, we now have to do the following:

• Select the root Runner node in your XCode project structure
• Select Runner below TARGETS
• Select the Build settings tab
• Click on the + to add a new User-defined setting
• Name it APP_FLAVOR
• Expand the node by clicking on the little arrow on the left of the row and add the actual flavor value to each build configuration:
  • Debug-dev: dev
  • Debug-uat: uat
  • Debug-live: live
  • Profile-dev: dev
  • Profile-uat: uat
  • Profile-live: live
  • Release-dev: dev
  • Release-uat: uat
  • Release-live: live

When done, it should look like this:

Setup App Name value per scheme

So open the Runner/Info.plist file in XCode and and modify Bundle display name with the following settings:

• Key: Bundle display name
• Type: String
• Value: $(APP_NAME)

We now have the key but we still don’t have the actual flavor-specific values per scheme. To add them, we now have to do the following:

• Select the root Runner node in your XCode project structure
• Select Runner below TARGETS
• Select the Build settings tab
• Click on the + to add a new User-defined setting
• Name it APP_NAME
• Expand the node by clicking on the little arrow on the left of the row and add the actual flavor value to each build configuration:
  • Debug-dev: DEV Cookify
  • Debug-uat: UAT Cookify
  • Debug-live: Cookify
  • Profile-dev: DEV Cookify
  • Profile-uat: UAT Cookify
  • Profile-live: Cookify
  • Release-dev: DEV Cookify
  • Release-uat: UAT Cookify
  • Release-live: Cookify

When done, it should look like this:

Setup Bundle Identifier value per scheme

• At the Build Settings tab
• Search Product Bundle
• Expand the node Product Bundle Identifier and modify actual Bundle ID value to each build configuration:
  • Debug-dev: com.andy.cookify.dev
  • Debug-uat: com.andy.cookify.uat
  • Debug-live: com.andy.cookify
  • Profile-dev: com.andy.cookify.dev
  • Profile-uat: com.andy.cookify.uat
  • Profile-live: com.andy.cookify
  • Release-dev: com.andy.cookify.dev
  • Release-uat: com.andy.cookify.uat
  • Release-live: com.andy.cookify

Adding the method channel for iOS

We need to add some code to the Runner/AppDelegate.swift in XCode. The finished file should look like this:

import UIKit
import Flutter

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    GeneratedPluginRegistrant.register(with: self)

    let controller = window.rootViewController as! FlutterViewController

    let flavorChannel = FlutterMethodChannel(
        name: "flavor",
        binaryMessenger: controller.binaryMessenger)

    flavorChannel.setMethodCallHandler({(call: FlutterMethodCall, result: @escaping FlutterResult) -> Void in
        // Note: this method is invoked on the UI thread
        let flavor = Bundle.main.infoDictionary?["App - Flavor"]
        result(flavor)
    })

    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}

This will set up a method channel handler that reads the current flavor from a Bundle.main.infoDictionary with a key called App - Flavor.