LiveData vs. Flow

Transcript

1. LiveData vs. Flow Jetpack or Kotlin?
2. LiveData
3. LiveData LiveData is an observable data holder class. Lifecycle-aware, which ensures it only updates app component observers that are in an active lifecycle state. “LiveData was never an RX replacement, we've been very clear about this from day 1” - Yigit Boyar
4. Drawbacks Operates mostly on the main thread. Nullable val liveData = MutableLiveData(0) liveData.value++ Part of the Android framework
5. Flow
6. Flow Kotlin Coroutine's Flow is a stream of data that can be asynchronously processed, similar to RxJava's Observable. It is a part of the Kotlin coroutines library and can be used to handle asynchronous operations in an easy and efficient way.
7. SharedFlow A hotFlow that shares emitted values among all its collectors in a broadcast fashion, so that all collectors get all emitted values. A shared flow is called hot because its active instance exists independently of the presence of collectors. This is opposed to a regular Flow, such as defined by the flow { ... } function, which is cold and is started separately for each collector. StateFlow A SharedFlow that represents a read-only state with a single updatable data value that emits updates to the value to its collectors. A state flow is a hot flow because its active instance exists independently of the presence of collectors. Its current value can be retrieved via the value property.
8. StateFlow In Android, StateFlow is a great fit for classes that need to maintain an observable mutable state. • Asynchronous • Transformations • Default value • Null friendly • Backpressure handling
9. Limitations No official way of surviving process death Not lifecycle aware by default StateFlow will re-emit again upon new subscription StateFlow doesn’t re-emit value that is the same
10. Lifecycle aware
11. Re-emit again upon new subscription
12. Resources • https://developer.android.com/topic/libraries/architecture/livedata • https://medium.com/mobile-app-development-publication/comparing-android-livedata-and-stateflow-b 2c430863b3a • https://kotlinlang.org/api/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.flow/-flow/ • https://kotlinlang.org/api/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.flow/-shared-flo w/ • https://kotlinlang.org/api/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.flow/-state-flow / • https://developer.android.com/kotlin/flow/stateflow-and-sharedflow • https://medium.com/androiddevelopers/migrating-from-livedata-to-kotlins-flow-379292f419fb