ViewModelProvider.get always gives unresolved reference

Issue

I'm trying to use ViewModel library in my app, I have created a class MainActivityViewModel which extends ViewModel class. When trying to instantiate the MainActivityViewModel class inside MainActivity by using ViewModelProvider.get(Class) the get method always results in an unresolved reference

MainActivityViewModel class:

class MainActivityViewModel: ViewModel() {
    private lateinit var mWords: MutableLiveData<List<Word>>

    fun getWords(): LiveData<List<Word>>{
        return mWords
    }
}

MainActivity class:

class MainActivity : AppCompatActivity() {

private lateinit var mMainActivityViewModel: MainActivityViewModel
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    val recycler = findViewById<RecyclerView>(R.id.recycler)
    recycler.adapter = RecyclerAdapter(this)
    recycler.layoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)

    mMainActivityViewModel = ViewModelProvider.get(MainActivityViewModel::class.java)
}

} I'm not sure what I'm doing wrong here,

the dependencies used for liveData:

def lifecycle_version = "2.2.0"
def arch_version = "2.1.0"
implementation 'androidx.core:core-ktx:1.3.2'
implementation "androidx.fragment:fragment-ktx:1.2.5"
// ViewModel
implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$lifecycle_version"
// LiveData
implementation "androidx.lifecycle:lifecycle-livedata-ktx:$lifecycle_version"
// Lifecycles only (without ViewModel or LiveData)
implementation "androidx.lifecycle:lifecycle-runtime-ktx:$lifecycle_version"

Thanks in advance

Solution

You need to pass in context, so ViewModel knows when it can be destoryed.

mMainActivityViewModel = ViewModelProvider(this).get(MainActivityViewModel::class.java)

Answered By - Shawn