Kotlin extension for LiveData, chaining like RxJava
To add LiveData KTX to your project, add the following to your app module's build.gradle:
implementation "com.shopify:livedata-ktx:VERSION"(See latest version on top of README)
val liveData: MutableLiveData<Boolean> = MutableLiveData()
liveData
.distinct()
.filter { it == false }
.map { true }
.nonNull()
.observe(lifecycleOwner, { result ->
// result is non-null and always true
})Because the input observer goes through a wrapper before it observes to source LiveData. So that you can't simply remove it by just calling origin method liveData.removeObserver.
The new observe method returns Removable interface that allows you to remove observer effectively.
val liveData: MutableLiveData<Boolean> = MutableLiveData()
val removable = liveData
.nonNull()
.observe(lifecycleOwner, {
// TODO
})
removable.removeObserver()It is a lifecycle-aware observable that sends only new updates after subscription, used for events like navigation and Snackbar messages. livedata-ktx has different implementation comparing to SingleLiveEvent from google samples android-architecture.
val liveData: MutableLiveData<Int> = SingleLiveData()
val actuals: MutableList<Int?> = mutableListOf()
val observer: (t: Int?) -> Unit = { actuals.add(it) }
liveData.value = 1
liveData.observe(this, observer)
liveData.value = 2
liveData.value = 3
val expecteds = mutableListOf(2, 3)
assertEquals(expecteds, actuals)For more use cases, please see the tests at LiveDataTest.kt
Please suggest what you need by creating issues. I will support it as fast as I can.
Any contributions are welcome!
Please check the CONTRIBUTING guideline before submitting a new issue. Wanna send PR? Click HERE
- Francisco Cavedon <@fcavedon>
- Henry Tao <@henrytao-me>
- Ivan Savytskyi <@sav007>
- Kris Orr <@krisorr>
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