Add backwards navigation from album to artist

Add a way for AlbumDetailFragment to return to ArtistDetailFragment.

app/src/main/java/org/oxycblt/auxio/MainActivity.kt

@@ -24,5 +24,6 @@ class MainActivity : AppCompatActivity() {
     }
 }
 
-// I wish I knew somewhere else to put this
+// RecyclerView click listener
+// Dont ask why its here
 class ClickListener<T>(val onClick: (T) -> Unit)

app/src/main/java/org/oxycblt/auxio/detail/AlbumDetailFragment.kt

@@ -7,6 +7,7 @@ import android.view.View
 import android.view.ViewGroup
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.activityViewModels
+import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
 import org.oxycblt.auxio.ClickListener
 import org.oxycblt.auxio.databinding.FragmentAlbumDetailBinding
@@ -17,6 +18,7 @@ import org.oxycblt.auxio.theme.applyDivider
 class AlbumDetailFragment : Fragment() {
 
     private val args: AlbumDetailFragmentArgs by navArgs()
+    private val detailModel: DetailViewModel by activityViewModels()
 
     override fun onCreateView(
         inflater: LayoutInflater,
@@ -31,6 +33,7 @@ class AlbumDetailFragment : Fragment() {
         val album = musicModel.albums.value?.find { it.id == args.albumId }!!
 
         binding.lifecycleOwner = this
+        binding.detailModel = detailModel
         binding.album = album
 
         binding.songRecycler.adapter = DetailSongAdapter(
@@ -42,6 +45,16 @@ class AlbumDetailFragment : Fragment() {
         binding.songRecycler.applyDivider()
         binding.songRecycler.setHasFixedSize(true)
 
+        detailModel.navToParentArtist.observe(viewLifecycleOwner) {
+            if (it) {
+                findNavController().navigate(
+                    AlbumDetailFragmentDirections.actionShowParentArtist(album.artist.id)
+                )
+
+                detailModel.doneWithNavToParent()
+            }
+        }
+
         Log.d(this::class.simpleName, "Fragment created.")
 
         return binding.root

app/src/main/java/org/oxycblt/auxio/detail/DetailViewModel.kt

@@ -1,7 +1,20 @@
 package org.oxycblt.auxio.detail
 
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 
 class DetailViewModel : ViewModel() {
     var isAlreadyNavigating = false
+
+    private val mNavToParentArtist = MutableLiveData<Boolean>()
+    val navToParentArtist: LiveData<Boolean> get() = mNavToParentArtist
+
+    fun navToParent() {
+        mNavToParentArtist.value = true
+    }
+
+    fun doneWithNavToParent() {
+        mNavToParentArtist.value = false
+    }
 }

app/src/main/java/org/oxycblt/auxio/music/MusicUtils.kt

@@ -45,6 +45,8 @@ fun String.toNamedGenre(): String? {
         PAREN_FILTER.indexOf(it) > -1
     }.toInt()
 
+    // If the conversion fails [Due to the genre using an extension that isn't from winamp],
+    // then return null.
     return ID3_GENRES.getOrNull(intGenre)
 }
 

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

@@ -8,6 +8,10 @@
         <variable
             name="album"
             type="org.oxycblt.auxio.music.models.Album" />
+
+        <variable
+            name="detailModel"
+            type="org.oxycblt.auxio.detail.DetailViewModel" />
     </data>
 
     <LinearLayout
@@ -69,10 +73,14 @@
 
                 <TextView
                     android:id="@+id/artist_name"
+                    android:background="@drawable/ripple"
+                    android:clickable="true"
+                    android:focusable="true"
                     android:layout_width="0dp"
                     android:layout_height="wrap_content"
                     android:textAppearance="?android:attr/textAppearanceListItem"
                     android:textColor="?android:attr/textColorSecondary"
+                    android:onClick="@{() -> detailModel.navToParent()}"
                     android:layout_marginStart="@dimen/margin_medium"
                     android:text="@{album.artist.name}"
                     app:layout_constraintStart_toStartOf="parent"

app/src/main/res/navigation/nav_main.xml

@@ -13,9 +13,12 @@
             android:id="@+id/action_to_main"
             app:destination="@id/main_fragment"
             app:enterAnim="@anim/fragment_fade_enter"
-            app:exitAnim="@anim/fragment_open_exit"
+            app:exitAnim="@anim/fragment_fade_exit"
+            app:popEnterAnim="@anim/fragment_fade_enter"
+            app:popExitAnim="@anim/fragment_fade_exit"
             app:popUpTo="@id/loading_fragment"
-            app:popUpToInclusive="true" />
+            app:popUpToInclusive="true"
+            app:launchSingleTop="true" />
     </fragment>
     <fragment
         android:id="@+id/main_fragment"
@@ -24,11 +27,12 @@
         tools:layout="@layout/fragment_main">
         <action
             android:id="@+id/action_show_artist"
-            app:destination="@id/artist_detail_fragment"
             app:enterAnim="@anim/fragment_fade_enter"
             app:exitAnim="@anim/fragment_fade_exit"
             app:popEnterAnim="@anim/fragment_fade_enter"
-            app:popExitAnim="@anim/fragment_fade_exit" />
+            app:popExitAnim="@anim/fragment_fade_exit"
+            app:destination="@id/artist_detail_fragment"
+            app:launchSingleTop="true" />
     </fragment>
     <fragment
         android:id="@+id/artist_detail_fragment"
@@ -54,5 +58,12 @@
         <argument
             android:name="albumId"
             app:argType="long" />
+        <action
+            android:id="@+id/action_show_parent_artist"
+            app:enterAnim="@anim/fragment_fade_enter"
+            app:exitAnim="@anim/fragment_fade_exit"
+            app:popEnterAnim="@anim/fragment_fade_enter"
+            app:popExitAnim="@anim/fragment_fade_exit"
+            app:destination="@id/artist_detail_fragment" />
     </fragment>
 </navigation>