LiveDataDSL

Generates DSL for LiveData observation.

loginViewModel.apply {
    mySampleLiveData(this@MainActivity) { userName ->
        println(userName)
        ...
    }
    liveDataWithoutLifeCycleOwner { userName ->
        println(userName)
        ...
    }
}

How to use

1. You need to add @LiveDataDSL annotation on your LiveData:

@LiveDataDSL
protected val sampleLiveData = MutableLiveData<String>()

@LiveDataDSL
protected val myOtherLiveData = MutableLiveData<Int>()

Also make sure that your LiveData has protected or public modifier.

2. Make sure that your view model class is extendable:

open class SampleViewModel : ViewModel() {
    ...
}

OR

abstract class SampleViewModel : ViewModel() {
    ...
}

3. Build your project, and use the generated ViewModel class in your view(Fragment, Activity or whatever).
   The generated ViewModel will be named ${ORIGINAL_CLASS_NAME}_DSL.kt, for example, if your ViewModel is named SampleViewModel.kt, then the generated ViewModel will be named SampleViewModel_DSL.kt

4. Use the generated ViewModel:

val sampleViewModel = ViewModelProviders.of(this)[SampleViewModel_DSL::class.java]
sampleViewModel.apply{
    sampleLiveData(this@MainActivity) {
        // This is where observation happens, you can use `it` receiver as observed value
        ...
    }
    myOtherLiveData(this@MainActivity) { myValue ->
        // This is where observation happens, you can use `myValue` receiver as observed value
        ...
    }
}

Observe without LifecycleOwner

You can also observe your live data without passing LifecycleOwner, but it will use observeForever.

private lateinit var function: FunctionResult<Observer<String>, LiveData<String>>

override fun onCreate(bundle: Bundle?) {
    val sampleViewModel = ViewModelProviders.of(this)[SampleViewModel_DSL::class.java]
    sampleViewModel.apply{
        function = sampleLiveData {
            // This is where observation happens, you can use `it` receiver as observed value
            ...
        }
        myOtherLiveData { myValue ->
            // This is where observation happens, you can use `myValue` receiver as observed value
            ...
        }
    }
}

override fun onDestroy() {
    super.onDestroy()
    function.apply { liveData.removeObservers(observer) }
}

Custom name for DSL function

You can set custom name for the DSL function through @LiveData(name = "customName").

open class SampleViewModel : ViewModel() {
    @LiveData("helloWorld")
    protected val customLiveData = MutableLiveData<Any>()
}

val sampleViewModel = ViewModelProviders.of(this)[SampleViewModel_DSL::class.java].apply {
    helloWorld {
        ...
    }
}

Dependency

dependencies {
    implementation "com.phelat:livedatadsl:1.0.0-alpha7"
    kapt "com.phelat:livedatadsl-processor:1.0.0-alpha7"
}

For AndroidX

dependencies {
    implementation "com.phelat:livedatadsl:1.0.0-alpha7"
    kapt "com.phelat:livedatadsl-processor-x:1.0.0-alpha7"
}