LiveData 와 MutableLiveData 차이강의중에서

해당코드를

viewModel = ViewModelProvider(this)[MainViewModel::class.java]

로 변경하니 오류가 사라지네요

캄사합니다

github 주소 올려두었습니다

github 주소입니당

https://github.com/dongguntechnology/ViewModelMutableLiveData

class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)

viewModel = ViewModelProvider(this).get(MainViewModel::class.java)

findViewById<Button>(R.id.btnArea).setOnClickListener {
viewModel.plusLiveDataValue()
}

viewModel.testLiveData.observe(this, Observer {
findViewById<TextView>(R.id.textArea).text = it.toString()
})
}
}

class MainViewModel {
private var testMutableLiveData = MutableLiveData(0)

val testLiveData : LiveData<Int> get() = testMutableLiveData

fun plusLiveDataValue(){
_testMutableLiveData.value = _testMutableLiveData.value!!.plus(1)
}


}