View model & view model factory setup

app/src/main/java/com/example/android/guesstheword/screens/score/ScoreFragment.kt

@@ -22,6 +22,8 @@ import android.view.View
 import android.view.ViewGroup
 import androidx.databinding.DataBindingUtil
 import androidx.fragment.app.Fragment
+import androidx.lifecycle.Observer
+import androidx.lifecycle.ViewModelProviders
 import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
 import com.example.android.guesstheword.R
@@ -32,6 +34,9 @@ import com.example.android.guesstheword.databinding.ScoreFragmentBinding
  */
 class ScoreFragment : Fragment() {
 
+    private lateinit var viewModel: ScoreViewModel
+    private lateinit var viewModelFactory: ScoreViewModelFactory
+
     override fun onCreateView(
             inflater: LayoutInflater,
             container: ViewGroup?,
@@ -46,15 +51,30 @@ class ScoreFragment : Fragment() {
                 false
         )
 
-        // Get args using by navArgs property delegate
         val scoreFragmentArgs by navArgs<ScoreFragmentArgs>()
-        binding.scoreText.text = scoreFragmentArgs.score.toString()
+        viewModelFactory = ScoreViewModelFactory(scoreFragmentArgs.score)
-        binding.playAgainButton.setOnClickListener { onPlayAgain() }
+        viewModel = ViewModelProviders.of(this, viewModelFactory)
+                .get(ScoreViewModel::class.java)
+
+        viewModel.score.observe(this, Observer {
+            binding.scoreText.text = getString(R.string.score_format, it)
+        })
+
+        viewModel.eventPlayAgain.observe(this, Observer {
+            if (it) {
+                onPlayAgain()
+            }
+        })
+
+        binding.playAgainButton.setOnClickListener {
+            viewModel.playAgain()
+        }
 
         return binding.root
     }
 
     private fun onPlayAgain() {
         findNavController().navigate(ScoreFragmentDirections.actionRestart())
+        viewModel.onPlayAgainComplete()
     }
 }

app/src/main/java/com/example/android/guesstheword/screens/score/ScoreViewModel.kt

@@ -0,0 +1,33 @@
+package com.example.android.guesstheword.screens.score
+
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.ViewModel
+import timber.log.Timber
+
+class ScoreViewModel(var finalScore:  Int): ViewModel() {
+
+    private val _score = MutableLiveData<Int>()
+    val score: LiveData<Int>
+        get() = _score
+
+
+    private val _eventPlayAgain = MutableLiveData<Boolean>()
+    val eventPlayAgain: LiveData<Boolean>
+        get() = _eventPlayAgain
+
+    init {
+        Timber.i("finalScore: $finalScore")
+        _eventPlayAgain.value = false
+        _score.value = finalScore
+    }
+
+    fun playAgain() {
+        _eventPlayAgain.value = true
+    }
+
+    fun onPlayAgainComplete() {
+        _eventPlayAgain.value = false
+    }
+}
+

app/src/main/java/com/example/android/guesstheword/screens/score/ScoreViewModelFactory.kt

@@ -0,0 +1,13 @@
+package com.example.android.guesstheword.screens.score
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+
+class ScoreViewModelFactory(private val finalScore: Int) : ViewModelProvider.Factory {
+    override fun <T : ViewModel?> create(modelClass: Class<T>): T {
+        if (modelClass.isAssignableFrom(ScoreViewModel::class.java)) {
+            // TODO Construct and return the ScoreViewModel
+        }
+        throw IllegalArgumentException("Unknown ViewModel class")
+    }
+}