Pass data from fragment with recyclerview to the other fragment using ViewModel in android

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I have a viewPager inside my application which contains 3 Fragments. First Fragment has a recyclerview on click of the item of recyclerview I pass some data to another fragment which is not the part of viewpager fragements. I am using the latest viewmodel logic to achieve this functionality and as per the steps mentioned by many websites I am doing the following this.

  1. Creating the separate class which extends viewmodel

    class MovieObservable : ViewModel() {

private val selectedMovieID = MutableLiveData<Int>()

fun setSelectedMovieID(id : Int){
    selectedMovieID.value = id 
}

fun getSelectedMovieID(): MutableLiveData<Int> {
    return selectedMovieID
}

  2. Initialize the viewmodel inside oncreateView Fragment 

    private lateinit var mViewModel : MovieObservable
mViewModel = ViewModelProvider(this).get(MovieObservable::class.java)

  3. Now from my RecyclerView I have implemented the click listener and implemented that in my fragment and override the onclick event with the position and value

    override fun onClickNowPlaying(position: Int, view: View, result: Result) {

System.out.println("now playing ID" + result.id)
mViewModel.setSelectedMovieID(result.id)
val newFragment = MovieDetailsFragment()
val transaction = activity?.supportFragmentManager?.beginTransaction()
transaction?.replace(R.id.mainLayout, newFragment, "NewFragment")
transaction?.addToBackStack(null)
transaction?.commit()
}

  4. I add the logic of observing the value in the details fragment which is below 

     private lateinit var mViewModel : MovieObservable
 mViewModel = ViewModelProvider(this).get(MovieObservable::class.java)
 mViewModel.getSelectedMovieID().observe(viewLifecycleOwner, Observer {getmydata->
    System.out.println("in the next fragment " + getmydata)
})

So All logic is finished to pass the data from one fragment to another but the problem is I am not getting the data on the details fragment. What is it which I am missing here.

android-viewmodel android-fragments android-recyclerview android
1 Answers

With latest library of ViewModel, it is even easier to create and share ViewModel between Fragments of Activity:

First add the activity-ktx and fragment-ktx dependencies in your app module's build.gradle:

dependencies {

    // For Activity
    def activity_version = "1.2.0-alpha04"
    implementation "androidx.activity:activity-ktx:$activity_version"

    // For Fragment
    def fragment_version = "1.3.0-alpha04"
    implementation "androidx.fragment:fragment-ktx:$fragment_version"

}

Suppose your ViewModel be as:

class MyViewModel : ViewModel() { }

Then, in your activity:

class MyActivity : AppCompatActivity() {

    // Use the 'by viewModels()' Kotlin property delegate 
    // from the activity-ktx artifact
    val model: MyViewModel by viewModels()
}

And then, your fragments would have:

class MyFirstFragment : Fragment() {

    // Use the 'by activityViewModels()' Kotlin property delegate
    // from the fragment-ktx artifact
    private val model: MyViewModel by activityViewModels()
}

class MySecondFragment : Fragment() {

    // Use the 'by activityViewModels()' Kotlin property delegate
    // from the fragment-ktx artifact
    private val model: MyViewModel by activityViewModels()
}
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