Techniques for Sharing Data Between Fragments in Kotlin

Techniques for Sharing Data Between Fragments in Kotlin

Fragments are a useful way to modularize the user interface of Android applications. They can be used to create complex layouts for activities, and they can also be reused in different activities. Fragments, however, can also be used to share data between different parts of an application. In this article, we will discuss some of the techniques for sharing data between fragments in Kotlin.

Using ViewModels

ViewModels are a great way to share data between fragments. A ViewModel is a class that provides data to the UI, and it allows you to save data when the UI is destroyed or recreated (e.g. when the device rotates). ViewModels are an effective way to share data between fragments as they are scoped to the Activity, meaning any fragment within that Activity will have access to the same data.

To use a ViewModel with fragments, you must first initialize the ViewModel in the Activity. Then each fragment will need to use the same ViewModel instance. To do this, each fragment must get a reference to the ViewModel from the Activity. This can be done by calling the ViewModelProvider's get() method. Finally, the ViewModel can be used to share data between the fragments.

Using Fragment Arguments

Another technique that can be used to share data between fragments is to pass data via fragment arguments. This can be done by creating a Bundle and adding the data to the Bundle. The Bundle then needs to be attached to the Fragment when it is created. When the Fragment is created, the Bundle will be passed to the Fragment in its onCreate() method and the data can be retrieved from the Bundle.

This technique is fairly simple and straightforward, but it has its limitations. Data passed via fragment arguments will not persist if the Fragment is destroyed and recreated (e.g. during rotation). Also, this technique only works for passing small amounts of data, as passing large amounts of data in a bundle can be slow and memory intensive.

Using Interfaces

Interfaces can also be used to share data between fragments. To use this technique, each fragment would need to implement the same interface. Then when data needs to be shared, one fragment can call a method on the interface and pass in the data. The other fragment will receive the data in its implementation of the interface method.

This technique is useful for sharing small amounts of data, such as user selections, but it should not be used for large amounts of data as it could become difficult to manage. Furthermore, this technique does not persist data if the app is restarted, as the interface will need to be re-implemented again.

Conclusion

In this article, we discussed some techniques for sharing data between fragments in Kotlin. We looked at using ViewModels, fragment arguments, and interfaces. Each technique has its own advantages and disadvantages, and it is important to choose the right technique for your specific scenario.