ui: split off selection from home

Split off selection functionality from the home fragment to a new
selection viewmodel.

It's going to be used elsewhere, so may as well.

README.md

@@ -48,7 +48,7 @@ I primarily built Auxio for myself, but you can use it too, I guess.
 - Customizable behavior
 - Seamless artist system that unifies album artist and artist tags
 - Advanced media indexer with support for multiple artists, release types,
-precise/original dates, sort tags, and more
+  precise/original dates, sort tags, and more
 - SD Card-aware folder management
 - Reliable playback state persistence
 - Full ReplayGain support (On MP3, MP4, FLAC, OGG, and OPUS)

app/src/main/java/org/oxycblt/auxio/detail/recycler/DetailAdapter.kt

@@ -59,7 +59,7 @@ abstract class DetailAdapter<L : DetailAdapter.Listener>(
         }
 
     override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) =
-        throw IllegalStateException()
+        throw NotImplementedError()
 
     override fun onBindViewHolder(
         holder: RecyclerView.ViewHolder,

app/src/main/java/org/oxycblt/auxio/home/HomeViewModel.kt

@@ -60,10 +60,6 @@ class HomeViewModel(application: Application) :
     val genres: StateFlow<List<Genre>>
         get() = _genres
 
-    private val _selected = MutableStateFlow(listOf<Music>())
-    val selected: StateFlow<List<Music>>
-        get() = _selected
-
     var tabs: List<MusicMode> = visibleTabs
         private set
 
@@ -88,19 +84,6 @@ class HomeViewModel(application: Application) :
         musicStore.addCallback(this)
     }
 
-    /** Select a music item. */
-    fun select(item: Music) {
-        val items = _selected.value.toMutableList()
-        if (items.remove(item)) {
-            logD("Unselecting item $item")
-            _selected.value = items
-        } else {
-            logD("Selecting item $item")
-            items.add(item)
-            _selected.value = items
-        }
-    }
-
     /** Update the current tab based off of the new ViewPager position. */
     fun updateCurrentTab(pos: Int) {
         logD("Updating current tab to ${tabs[pos]}")

app/src/main/java/org/oxycblt/auxio/home/list/AlbumListFragment.kt

@@ -56,7 +56,7 @@ class AlbumListFragment : HomeListFragment<Album>() {
         }
 
         collectImmediately(homeModel.albums, homeAdapter::replaceList)
-        collectImmediately(homeModel.selected, homeAdapter::updateSelection)
+        collectImmediately(selectionModel.selected, homeAdapter::updateSelection)
         collectImmediately(playbackModel.parent, playbackModel.isPlaying, ::handleParent)
     }
 

app/src/main/java/org/oxycblt/auxio/home/list/ArtistListFragment.kt

@@ -52,7 +52,7 @@ class ArtistListFragment : HomeListFragment<Artist>() {
         }
 
         collectImmediately(homeModel.artists, homeAdapter::replaceList)
-        collectImmediately(homeModel.selected, homeAdapter::updateSelection)
+        collectImmediately(selectionModel.selected, homeAdapter::updateSelection)
         collectImmediately(playbackModel.parent, playbackModel.isPlaying, ::handleParent)
     }
 

app/src/main/java/org/oxycblt/auxio/home/list/GenreListFragment.kt

@@ -51,7 +51,7 @@ class GenreListFragment : HomeListFragment<Genre>() {
         }
 
         collectImmediately(homeModel.genres, homeAdapter::replaceList)
-        collectImmediately(homeModel.selected, homeAdapter::updateSelection)
+        collectImmediately(selectionModel.selected, homeAdapter::updateSelection)
         collectImmediately(playbackModel.parent, playbackModel.isPlaying, ::handlePlayback)
     }
 

app/src/main/java/org/oxycblt/auxio/home/list/HomeListFragment.kt

@@ -20,9 +20,11 @@ package org.oxycblt.auxio.home.list
 import android.os.Bundle
 import android.view.LayoutInflater
 import androidx.fragment.app.Fragment
+import androidx.fragment.app.activityViewModels
 import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 import org.oxycblt.auxio.home.HomeViewModel
 import org.oxycblt.auxio.music.Music
+import org.oxycblt.auxio.ui.SelectionViewModel
 import org.oxycblt.auxio.ui.fastscroll.FastScrollRecyclerView
 import org.oxycblt.auxio.ui.fragment.MenuFragment
 import org.oxycblt.auxio.ui.recycler.Item
@@ -39,6 +41,7 @@ abstract class HomeListFragment<T : Item> :
     FastScrollRecyclerView.PopupProvider,
     FastScrollRecyclerView.OnFastScrollListener {
     protected val homeModel: HomeViewModel by androidActivityViewModels()
+    protected val selectionModel: SelectionViewModel by activityViewModels()
 
     override fun onCreateBinding(inflater: LayoutInflater) =
         FragmentHomeListBinding.inflate(inflater)
@@ -69,7 +72,7 @@ abstract class HomeListFragment<T : Item> :
 
     override fun onItemClick(item: Item) {
         check(item is Music) { "Unexpected datatype: ${item::class.java}" }
-        if (homeModel.selected.value.isEmpty()) {
+        if (selectionModel.selected.value.isEmpty()) {
             onItemClick(item)
         } else {
             onSelect(item)
@@ -78,6 +81,6 @@ abstract class HomeListFragment<T : Item> :
 
     override fun onSelect(item: Item) {
         check(item is Music) { "Unexpected datatype: ${item::class.java}" }
-        homeModel.select(item)
+        selectionModel.select(item)
     }
 }

app/src/main/java/org/oxycblt/auxio/home/list/SongListFragment.kt

@@ -59,7 +59,7 @@ class SongListFragment : HomeListFragment<Song>() {
         }
 
         collectImmediately(homeModel.songs, homeAdapter::replaceList)
-        collectImmediately(homeModel.selected, homeAdapter::updateSelection)
+        collectImmediately(selectionModel.selected, homeAdapter::updateSelection)
         collectImmediately(
             playbackModel.song, playbackModel.parent, playbackModel.isPlaying, ::handlePlayback)
     }

app/src/main/java/org/oxycblt/auxio/ui/SelectionViewModel.kt

@@ -0,0 +1,26 @@
+package org.oxycblt.auxio.ui
+
+import androidx.lifecycle.ViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import org.oxycblt.auxio.music.Music
+import org.oxycblt.auxio.util.logD
+
+class SelectionViewModel : ViewModel() {
+    private val _selected = MutableStateFlow(listOf<Music>())
+    val selected: StateFlow<List<Music>>
+        get() = _selected
+
+    /** Select a music item. */
+    fun select(item: Music) {
+        val items = _selected.value.toMutableList()
+        if (items.remove(item)) {
+            logD("Unselecting item $item")
+            _selected.value = items
+        } else {
+            logD("Selecting item $item")
+            items.add(item)
+            _selected.value = items
+        }
+    }
+}

app/src/main/res/layout-h600dp/item_detail.xml

@@ -65,7 +65,7 @@
         style="@style/Widget.Auxio.Button.Secondary"
         android:layout_width="0dp"
         android:layout_height="wrap_content"
-        android:layout_marginTop="@dimen/spacing_medium"
+        android:layout_marginTop="@dimen/spacing_mid_medium"
         android:layout_marginEnd="@dimen/spacing_small"
         android:text="@string/lbl_play"
         app:layout_constraintEnd_toStartOf="@+id/detail_shuffle_button"

app/src/main/res/layout-land/item_detail.xml

@@ -79,7 +79,7 @@
         style="@style/Widget.Auxio.Button.Secondary"
         android:layout_width="0dp"
         android:layout_height="wrap_content"
-        android:layout_marginTop="@dimen/spacing_medium"
+        android:layout_marginTop="@dimen/spacing_mid_medium"
         android:layout_marginEnd="@dimen/spacing_small"
         android:text="@string/lbl_play"
         app:layout_constraintEnd_toStartOf="@+id/detail_shuffle_button"

app/src/main/res/layout-sw600dp/item_detail.xml

@@ -79,7 +79,7 @@
         android:layout_width="0dp"
         android:layout_height="wrap_content"
         android:layout_marginStart="@dimen/spacing_medium"
-        android:layout_marginTop="@dimen/spacing_medium"
+        android:layout_marginTop="@dimen/spacing_mid_medium"
         android:layout_marginEnd="@dimen/spacing_small"
         android:text="@string/lbl_play"
         app:layout_constraintBottom_toBottomOf="@+id/detail_cover"

app/src/main/res/layout-sw840dp/item_detail.xml

@@ -75,7 +75,7 @@
         android:layout_width="0dp"
         android:layout_height="wrap_content"
         android:layout_marginStart="@dimen/spacing_medium"
-        android:layout_marginTop="@dimen/spacing_medium"
+        android:layout_marginTop="@dimen/spacing_mid_medium"
         android:layout_marginEnd="@dimen/spacing_small"
         android:text="@string/lbl_play"
         app:layout_constraintBottom_toBottomOf="@+id/detail_cover"

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

@@ -68,7 +68,7 @@
         style="@style/Widget.Auxio.Button.Secondary"
         android:layout_width="0dp"
         android:layout_height="wrap_content"
-        android:layout_marginTop="@dimen/spacing_medium"
+        android:layout_marginTop="@dimen/spacing_mid_medium"
         android:layout_marginEnd="@dimen/spacing_small"
         android:text="@string/lbl_play"
         app:layout_constraintEnd_toStartOf="@+id/detail_shuffle_button"