Feature Toggles

Remote feature control in mobile applications is a powerful tool that allows developers to manage features without the need to update the application. Through strategies such as Feature Flags or Feature Toggles, we can enable or disable features as needed, providing a more controlled and personalized user experience.

What are Feature Flags and why are they important?

Feature Flags or Feature Toggles are one of the most used strategies in application development because they give us full control over our features. This technique allows us to turn specific features on or off when we need to, either to:

• Disable features that present unexpected errors.
• Enable features only for certain groups of users
• Perform A/B testing in a controlled manner
• Implement gradual rollouts of new features

This flexibility is crucial to maintain the stability of the application while introducing new features, allowing us to respond quickly to problems without the need to release emergency updates.

How to implement a styling system controlled by Firebase Remote Config?

To implement a system that allows us to change the styling of our application remotely, we need to modify our ViewModel to receive and process the styling parameters from Firebase. Let's see how to do it step by step:

Configuring the ViewModel

First, we must create a constant that receives the style parameter that we set in Firebase:

private val style = "style"

Then, we create a color map that associates the received values with the corresponding styles:

private val colorMap = mapOf( " whitestyle" to Color.WHITE, " blackstyle" to Color.BLACK, " default" to Color.GRAY)

This map allows us to define that if we receive "whitestyle", we will display a white background; if we receive "blackstyle", a black background; and if we do not receive any specific value, we will use a default gray background.

Storing the style value

Next, we need variables to store and expose the style value:

private val _colorStyle = MutableStateFlow(colorMap["default"])val colorStyle: StateFlow<Color> = _colorStyle.

Getting the value from Remote Config

In our initialization function (fetchActive), we implement the logic to get the value from Firebase Remote Config:

fun fetchActive() { // Existing code...    
 val colorString = remoteConfig.getString(style) _colorStyle.value = colorMap[colorString] ?: colorMap["default"]}

With this, we are receiving the value configured in Remote Config and assigning it to our StateFlow, which will then be observed by the UI to apply the corresponding style.

How to configure default values for when there is no connection?

It is important to have default values in case the user has no internet connection. Firebase Remote Config allows us to download a configuration file that we can include in our application:

1. In the Firebase console, look for the option to download the current configuration file.
2. Download the file to your computer
3. Drag the file to your project, specifically to the XML folder.

This file will contain the default values you have configured in Firebase, and the application will use them when it cannot connect to the internet to get the latest configuration.

Verifying the operation

Once everything is implemented, we can compile our application to verify that everything works correctly. If the configuration has been read correctly, we should see a confirmation message and our application should respond to the style changes configured in Firebase.

Feature Flags give us full control over our applications even after launch, allowing us to hide or show functionality as needed. This flexibility is invaluable for managing the lifecycle of our applications and providing the best possible experience for our users. I encourage you to experiment with Remote Config settings and discover how they can improve the development and maintenance of your applications. If you have questions or want to share your experiences, feel free to leave your comments.