Refactor RecipesFragment

This commit extracts SwipeRefreshLayout extension to a
separate file. Additionally, it refactors RecipesFragment in
order to move all the logic to the ViewModel from the View.

app/src/main/java/gq/kirmanak/mealient/ui/SwipeRefreshLayoutHelper.kt

@@ -1,41 +0,0 @@
-package gq.kirmanak.mealient.ui
-
-import androidx.paging.PagingDataAdapter
-import androidx.recyclerview.widget.RecyclerView
-import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
-import kotlinx.coroutines.ExperimentalCoroutinesApi
-import kotlinx.coroutines.channels.awaitClose
-import kotlinx.coroutines.channels.onFailure
-import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.callbackFlow
-import kotlinx.coroutines.flow.collectLatest
-import timber.log.Timber
-
-@ExperimentalCoroutinesApi
-object SwipeRefreshLayoutHelper {
-    private fun SwipeRefreshLayout.refreshesFlow(): Flow<Unit> {
-        Timber.v("refreshesFlow() called")
-        return callbackFlow {
-            val listener = SwipeRefreshLayout.OnRefreshListener {
-                Timber.v("Refresh requested")
-                trySend(Unit).onFailure { Timber.e(it, "Can't send refresh callback") }
-            }
-            Timber.v("Adding refresh request listener")
-            setOnRefreshListener(listener)
-            awaitClose {
-                Timber.v("Removing refresh request listener")
-                setOnRefreshListener(null)
-            }
-        }
-    }
-
-    suspend fun <T : Any, VH : RecyclerView.ViewHolder> PagingDataAdapter<T, VH>.listenToRefreshRequests(
-        refreshLayout: SwipeRefreshLayout
-    ) {
-        Timber.v("listenToRefreshRequests() called")
-        refreshLayout.refreshesFlow().collectLatest {
-            Timber.d("Received refresh request")
-            refresh()
-        }
-    }
-}

app/src/main/java/gq/kirmanak/mealient/ui/ViewExtensions.kt

@@ -0,0 +1,31 @@
+package gq.kirmanak.mealient.ui
+
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.asLiveData
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.channels.awaitClose
+import kotlinx.coroutines.channels.onClosed
+import kotlinx.coroutines.channels.onFailure
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.callbackFlow
+import timber.log.Timber
+
+@ExperimentalCoroutinesApi
+fun SwipeRefreshLayout.refreshesLiveData(): LiveData<Unit> {
+    val callbackFlow: Flow<Unit> = callbackFlow {
+        val listener = SwipeRefreshLayout.OnRefreshListener {
+            Timber.v("Refresh requested")
+            trySend(Unit)
+                .onFailure { Timber.e(it, "refreshesFlow: can't send refresh callback") }
+                .onClosed { Timber.e(it, "refreshesFlow: flow has been closed") }
+        }
+        Timber.v("Adding refresh request listener")
+        setOnRefreshListener(listener)
+        awaitClose {
+            Timber.v("Removing refresh request listener")
+            setOnRefreshListener(null)
+        }
+    }
+    return callbackFlow.asLiveData()
+}

app/src/main/java/gq/kirmanak/mealient/ui/recipes/RecipeViewModel.kt

@@ -1,22 +1,43 @@
 package gq.kirmanak.mealient.ui.recipes
 
 import android.widget.ImageView
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import androidx.paging.cachedIn
 import dagger.hilt.android.lifecycle.HiltViewModel
 import gq.kirmanak.mealient.data.recipes.RecipeImageLoader
 import gq.kirmanak.mealient.data.recipes.RecipeRepo
 import gq.kirmanak.mealient.data.recipes.db.entity.RecipeSummaryEntity
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.launch
 import timber.log.Timber
 import javax.inject.Inject
 
 @HiltViewModel
 class RecipeViewModel @Inject constructor(
-    recipeRepo: RecipeRepo,
+    private val recipeRepo: RecipeRepo,
     private val recipeImageLoader: RecipeImageLoader
 ) : ViewModel() {
-    val recipeFlow = recipeRepo.createPager().flow
+    private var _isRefreshing = MutableLiveData<Boolean>()
+    val isRefreshing: LiveData<Boolean> get() = _isRefreshing
+
+    private val _nextRecipeInfoChannel = Channel<RecipeSummaryEntity>()
+    val nextRecipeInfo: Flow<RecipeSummaryEntity> =
+        _nextRecipeInfoChannel.receiveAsFlow()
+
+    val adapter = RecipesPagingAdapter(this) {
+        Timber.d("onClick: recipe clicked $it")
+        viewModelScope.launch { _nextRecipeInfoChannel.send(it) }
+    }
+
+    init {
+        setupAdapter()
+    }
 
     fun loadRecipeImage(view: ImageView, recipeSummary: RecipeSummaryEntity?) {
         Timber.v("loadRecipeImage() called with: view = $view, recipeSummary = $recipeSummary")
@@ -24,4 +45,21 @@ class RecipeViewModel @Inject constructor(
             recipeImageLoader.loadRecipeImage(view, recipeSummary?.slug)
         }
     }
+
+    private fun setupAdapter() {
+        with(viewModelScope) {
+            launch {
+                recipeRepo.createPager().flow.cachedIn(this).collect {
+                    Timber.d("setupAdapter: received data update")
+                    adapter.submitData(it)
+                }
+            }
+            launch {
+                adapter.onPagesUpdatedFlow.collect {
+                    Timber.d("setupAdapter: pages have been updated")
+                    _isRefreshing.value = false
+                }
+            }
+        }
+    }
 }

app/src/main/java/gq/kirmanak/mealient/ui/recipes/RecipesFragment.kt

@@ -10,12 +10,11 @@ import androidx.fragment.app.viewModels
 import androidx.lifecycle.Observer
 import androidx.lifecycle.lifecycleScope
 import androidx.navigation.fragment.findNavController
-import androidx.recyclerview.widget.LinearLayoutManager
 import dagger.hilt.android.AndroidEntryPoint
 import gq.kirmanak.mealient.data.recipes.db.entity.RecipeSummaryEntity
 import gq.kirmanak.mealient.databinding.FragmentRecipesBinding
-import gq.kirmanak.mealient.ui.SwipeRefreshLayoutHelper.listenToRefreshRequests
 import gq.kirmanak.mealient.ui.auth.AuthenticationViewModel
+import gq.kirmanak.mealient.ui.refreshesLiveData
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.collect
 import timber.log.Timber
@@ -74,22 +73,19 @@ class RecipesFragment : Fragment() {
 
     private fun setupRecipeAdapter() {
         Timber.v("setupRecipeAdapter() called")
-        binding.recipes.layoutManager = LinearLayoutManager(requireContext())
+        binding.recipes.adapter = viewModel.adapter
-        val adapter = RecipesPagingAdapter(viewModel) { navigateToRecipeInfo(it) }
+        viewModel.isRefreshing.observe(viewLifecycleOwner) {
-        binding.recipes.adapter = adapter
+            Timber.d("setupRecipeAdapter: isRefreshing = $it")
-        viewLifecycleOwner.lifecycleScope.launchWhenResumed {
+            binding.refresher.isRefreshing = it
-            viewModel.recipeFlow.collect {
+        }
-                Timber.d("Received update")
+        binding.refresher.refreshesLiveData().observe(viewLifecycleOwner) {
-                adapter.submitData(it)
+            Timber.d("setupRecipeAdapter: received refresh request")
-            }
+            viewModel.adapter.refresh()
         }
         viewLifecycleOwner.lifecycleScope.launchWhenResumed {
-            adapter.listenToRefreshRequests(binding.refresher)
+            viewModel.nextRecipeInfo.collect {
-        }
+                Timber.d("setupRecipeAdapter: navigating to recipe $it")
-        viewLifecycleOwner.lifecycleScope.launchWhenResumed {
+                navigateToRecipeInfo(it)
-            adapter.onPagesUpdatedFlow.collect {
-                Timber.d("Pages have been updated")
-                binding.refresher.isRefreshing = false
             }
         }
     }

app/src/main/res/layout/fragment_recipes.xml

@@ -19,6 +19,7 @@
 			android:id="@+id/recipes"
 			android:layout_width="match_parent"
 			android:layout_height="match_parent"
+			app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
 			tools:listitem="@layout/view_holder_recipe" />
 	</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>