ui: use event everywhere

Replace all prior uses of the StateFlow + finish method pattern with
the new event class.

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

@@ -129,12 +129,12 @@ class MainFragment :
         }
 
         // --- VIEWMODEL SETUP ---
-        collect(navModel.mainNavigationAction, ::handleMainNavigation)
+        collect(navModel.mainNavigationAction.flow, ::handleMainNavigation)
-        collect(navModel.exploreNavigationItem, ::handleExploreNavigation)
+        collect(navModel.exploreNavigationItem.flow, ::handleExploreNavigation)
-        collect(navModel.exploreArtistNavigationItem, ::handleArtistNavigationPicker)
+        collect(navModel.exploreArtistNavigationItem.flow, ::handleArtistNavigationPicker)
         collectImmediately(playbackModel.song, ::updateSong)
-        collect(playbackModel.artistPickerSong, ::handlePlaybackArtistPicker)
+        collect(playbackModel.artistPickerSong.flow, ::handlePlaybackArtistPicker)
-        collect(playbackModel.genrePickerSong, ::handlePlaybackGenrePicker)
+        collect(playbackModel.genrePickerSong.flow, ::handlePlaybackGenrePicker)
     }
 
     override fun onStart() {
@@ -273,7 +273,7 @@ class MainFragment :
             is MainNavigationAction.Directions -> findNavController().navigate(action.directions)
         }
 
-        navModel.finishMainNavigation()
+        navModel.mainNavigationAction.consume()
     }
 
     private fun handleExploreNavigation(item: Music?) {
@@ -287,7 +287,7 @@ class MainFragment :
             navModel.mainNavigateTo(
                 MainNavigationAction.Directions(
                     MainFragmentDirections.actionPickNavigationArtist(item.uid)))
-            navModel.finishExploreNavigation()
+            navModel.exploreArtistNavigationItem.consume()
         }
     }
 
@@ -304,7 +304,7 @@ class MainFragment :
             navModel.mainNavigateTo(
                 MainNavigationAction.Directions(
                     MainFragmentDirections.actionPickPlaybackArtist(song.uid)))
-            playbackModel.finishPlaybackArtistPicker()
+            playbackModel.artistPickerSong.consume()
         }
     }
 
@@ -313,7 +313,7 @@ class MainFragment :
             navModel.mainNavigateTo(
                 MainNavigationAction.Directions(
                     MainFragmentDirections.actionPickPlaybackGenre(song.uid)))
-            playbackModel.finishPlaybackGenrePicker()
+            playbackModel.genrePickerSong.consume()
         }
     }
 

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

@@ -96,7 +96,7 @@ class AlbumDetailFragment :
         collectImmediately(detailModel.albumList, ::updateList)
         collectImmediately(
             playbackModel.song, playbackModel.parent, playbackModel.isPlaying, ::updatePlayback)
-        collect(navModel.exploreNavigationItem, ::handleNavigation)
+        collect(navModel.exploreNavigationItem.flow, ::handleNavigation)
         collectImmediately(selectionModel.selected, ::updateSelection)
     }
 
@@ -205,7 +205,7 @@ class AlbumDetailFragment :
                 if (unlikelyToBeNull(detailModel.currentAlbum.value) == item.album) {
                     logD("Navigating to a song in this album")
                     scrollToAlbumSong(item)
-                    navModel.finishExploreNavigation()
+                    navModel.exploreNavigationItem.consume()
                 } else {
                     logD("Navigating to another album")
                     findNavController()
@@ -219,7 +219,7 @@ class AlbumDetailFragment :
                 if (unlikelyToBeNull(detailModel.currentAlbum.value) == item) {
                     logD("Navigating to the top of this album")
                     binding.detailRecycler.scrollToPosition(0)
-                    navModel.finishExploreNavigation()
+                    navModel.exploreNavigationItem.consume()
                 } else {
                     logD("Navigating to another album")
                     findNavController()

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

@@ -99,7 +99,7 @@ class ArtistDetailFragment :
         collectImmediately(detailModel.artistList, ::updateList)
         collectImmediately(
             playbackModel.song, playbackModel.parent, playbackModel.isPlaying, ::updatePlayback)
-        collect(navModel.exploreNavigationItem, ::handleNavigation)
+        collect(navModel.exploreNavigationItem.flow, ::handleNavigation)
         collectImmediately(selectionModel.selected, ::updateSelection)
     }
 
@@ -240,7 +240,7 @@ class ArtistDetailFragment :
                 if (item.uid == detailModel.currentArtist.value?.uid) {
                     logD("Navigating to the top of this artist")
                     binding.detailRecycler.scrollToPosition(0)
-                    navModel.finishExploreNavigation()
+                    navModel.exploreNavigationItem.consume()
                 } else {
                     logD("Navigating to another artist")
                     findNavController()

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

@@ -98,7 +98,7 @@ class GenreDetailFragment :
         collectImmediately(detailModel.genreList, ::updateList)
         collectImmediately(
             playbackModel.song, playbackModel.parent, playbackModel.isPlaying, ::updatePlayback)
-        collect(navModel.exploreNavigationItem, ::handleNavigation)
+        collect(navModel.exploreNavigationItem.flow, ::handleNavigation)
         collectImmediately(selectionModel.selected, ::updateSelection)
     }
 
@@ -229,7 +229,7 @@ class GenreDetailFragment :
                     .navigate(GenreDetailFragmentDirections.actionShowArtist(item.uid))
             }
             is Genre -> {
-                navModel.finishExploreNavigation()
+                navModel.exploreNavigationItem.consume()
             }
             null -> {}
         }

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

@@ -155,11 +155,11 @@ class HomeFragment :
         binding.homeFab.setOnClickListener { playbackModel.shuffleAll() }
 
         // --- VIEWMODEL SETUP ---
-        collect(homeModel.shouldRecreate.flow, ::handleRecreate)
+        collect(homeModel.recreateTabs.flow, ::handleRecreate)
         collectImmediately(homeModel.currentTabMode, ::updateCurrentTab)
         collectImmediately(homeModel.songsList, homeModel.isFastScrolling, ::updateFab)
         collectImmediately(musicModel.indexerState, ::updateIndexerState)
-        collect(navModel.exploreNavigationItem, ::handleNavigation)
+        collect(navModel.exploreNavigationItem.flow, ::handleNavigation)
         collectImmediately(selectionModel.selected, ::updateSelection)
     }
 
@@ -337,7 +337,7 @@ class HomeFragment :
         binding.homePager.currentItem = 0
         // Make sure tabs are set up to also follow the new ViewPager configuration.
         setupPager(binding)
-        homeModel.shouldRecreate.consume()
+        homeModel.recreateTabs.consume()
     }
 
     private fun updateIndexerState(state: Indexer.State?) {

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

@@ -109,7 +109,7 @@ constructor(
      * flag is true, all tabs (and their respective ViewPager2 fragments) will be re-created from
      * scratch.
      */
-    val shouldRecreate: Event<Unit>
+    val recreateTabs: Event<Unit>
         get() = _shouldRecreate
 
     private val _isFastScrolling = MutableStateFlow(false)

app/src/main/java/org/oxycblt/auxio/playback/PlaybackViewModel.kt

@@ -31,6 +31,8 @@ import org.oxycblt.auxio.music.*
 import org.oxycblt.auxio.playback.persist.PersistenceRepository
 import org.oxycblt.auxio.playback.queue.Queue
 import org.oxycblt.auxio.playback.state.*
+import org.oxycblt.auxio.util.Event
+import org.oxycblt.auxio.util.MutableEvent
 
 /**
  * An [ViewModel] that provides a safe UI frontend for the current playback state.
@@ -74,22 +76,22 @@ constructor(
     val isShuffled: StateFlow<Boolean>
         get() = _isShuffled
 
-    private val _artistPlaybackPickerSong = MutableStateFlow<Song?>(null)
+    private val _artistPlaybackPickerSong = MutableEvent<Song>()
     /**
      * Flag signaling to open a picker dialog in order to resolve an ambiguous choice when playing a
      * [Song] from one of it's [Artist]s.
      *
      * @see playFromArtist
      */
-    val artistPickerSong: StateFlow<Song?>
+    val artistPickerSong: Event<Song>
         get() = _artistPlaybackPickerSong
 
-    private val _genrePlaybackPickerSong = MutableStateFlow<Song?>(null)
+    private val _genrePlaybackPickerSong = MutableEvent<Song>()
     /**
      * Flag signaling to open a picker dialog in order to resolve an ambiguous choice when playing a
      * [Song] from one of it's [Genre]s.
      */
-    val genrePickerSong: StateFlow<Song?>
+    val genrePickerSong: Event<Song>
         get() = _genrePlaybackPickerSong
 
     /** The current action to show on the playback bar. */
@@ -192,20 +194,10 @@ constructor(
         } else if (song.artists.size == 1) {
             playImpl(song, song.artists[0])
         } else {
-            _artistPlaybackPickerSong.value = song
+            _artistPlaybackPickerSong.put(song)
         }
     }
 
-    /**
-     * Mark the [Artist] playback choice process as complete. This should occur when the [Artist]
-     * choice dialog is opened after this flag is detected.
-     *
-     * @see playFromArtist
-     */
-    fun finishPlaybackArtistPicker() {
-        _artistPlaybackPickerSong.value = null
-    }
-
     /**
      * PLay a [Song] from one of it's [Genre]s.
      *
@@ -219,20 +211,10 @@ constructor(
         } else if (song.genres.size == 1) {
             playImpl(song, song.genres[0])
         } else {
-            _genrePlaybackPickerSong.value = song
+            _genrePlaybackPickerSong.put(song)
         }
     }
 
-    /**
-     * Mark the [Genre] playback choice process as complete. This should occur when the [Genre]
-     * choice dialog is opened after this flag is detected.
-     *
-     * @see playFromGenre
-     */
-    fun finishPlaybackGenrePicker() {
-        _genrePlaybackPickerSong.value = null
-    }
-
     /**
      * Play an [Album].
      *

app/src/main/java/org/oxycblt/auxio/search/SearchFragment.kt

@@ -115,7 +115,7 @@ class SearchFragment : ListFragment<Music, FragmentSearchBinding>() {
         collectImmediately(searchModel.searchResults, ::updateSearchResults)
         collectImmediately(
             playbackModel.song, playbackModel.parent, playbackModel.isPlaying, ::updatePlayback)
-        collect(navModel.exploreNavigationItem, ::handleNavigation)
+        collect(navModel.exploreNavigationItem.flow, ::handleNavigation)
         collectImmediately(selectionModel.selected, ::updateSelection)
     }
 

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

@@ -20,38 +20,38 @@ package org.oxycblt.auxio.ui
 
 import androidx.lifecycle.ViewModel
 import androidx.navigation.NavDirections
-import kotlinx.coroutines.flow.MutableStateFlow
-import kotlinx.coroutines.flow.StateFlow
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.util.Event
+import org.oxycblt.auxio.util.MutableEvent
 import org.oxycblt.auxio.util.logD
 
 /** A [ViewModel] that handles complicated navigation functionality. */
 class NavigationViewModel : ViewModel() {
-    private val _mainNavigationAction = MutableStateFlow<MainNavigationAction?>(null)
+    private val _mainNavigationAction = MutableEvent<MainNavigationAction>()
     /**
      * Flag for navigation within the main navigation graph. Only intended for use by MainFragment.
      */
-    val mainNavigationAction: StateFlow<MainNavigationAction?>
+    val mainNavigationAction: Event<MainNavigationAction>
         get() = _mainNavigationAction
 
-    private val _exploreNavigationItem = MutableStateFlow<Music?>(null)
+    private val _exploreNavigationItem = MutableEvent<Music>()
     /**
      * Flag for navigation within the explore navigation graph. Observe this to coordinate
      * navigation to a specific [Music] item.
      */
-    val exploreNavigationItem: StateFlow<Music?>
+    val exploreNavigationItem: Event<Music>
         get() = _exploreNavigationItem
 
-    private val _exploreArtistNavigationItem = MutableStateFlow<Music?>(null)
+    private val _exploreArtistNavigationItem = MutableEvent<Music>()
     /**
      * Variation of [exploreNavigationItem] for situations where the choice of parent [Artist] to
      * navigate to is ambiguous. Only intended for use by MainFragment, as the resolved choice will
      * eventually be assigned to [exploreNavigationItem].
      */
-    val exploreArtistNavigationItem: StateFlow<Music?>
+    val exploreArtistNavigationItem: Event<Music>
         get() = _exploreArtistNavigationItem
 
     /**
@@ -62,21 +62,12 @@ class NavigationViewModel : ViewModel() {
      * @param action The [MainNavigationAction] to perform.
      */
     fun mainNavigateTo(action: MainNavigationAction) {
-        if (_mainNavigationAction.value != null) {
+        if (_mainNavigationAction.flow.value != null) {
             logD("Already navigating, not doing main action")
             return
         }
         logD("Navigating with action $action")
-        _mainNavigationAction.value = action
+        _mainNavigationAction.put(action)
-    }
-
-    /**
-     * Mark that the navigation process within the main navigation graph (initiated by
-     * [mainNavigateTo]) was completed.
-     */
-    fun finishMainNavigation() {
-        logD("Finishing main navigation process")
-        _mainNavigationAction.value = null
     }
 
     /**
@@ -85,12 +76,12 @@ class NavigationViewModel : ViewModel() {
      * @param music The [Music] to navigate to.
      */
     fun exploreNavigateTo(music: Music) {
-        if (_exploreNavigationItem.value != null) {
+        if (_exploreNavigationItem.flow.value != null) {
             logD("Already navigating, not doing explore action")
             return
         }
         logD("Navigating to ${music.rawName}")
-        _exploreNavigationItem.value = music
+        _exploreNavigationItem.put(music)
     }
 
     /**
@@ -114,7 +105,7 @@ class NavigationViewModel : ViewModel() {
     }
 
     private fun exploreNavigateToParentArtistImpl(item: Music, artists: List<Artist>) {
-        if (_exploreArtistNavigationItem.value != null) {
+        if (_exploreArtistNavigationItem.flow.value != null) {
             logD("Already navigating, not doing explore action")
             return
         }
@@ -123,19 +114,9 @@ class NavigationViewModel : ViewModel() {
             exploreNavigateTo(artists[0])
         } else {
             logD("Navigating to a choice of ${artists.map { it.rawName }}")
-            _exploreArtistNavigationItem.value = item
+            _exploreArtistNavigationItem.put(item)
         }
     }
-
-    /**
-     * Mark that the navigation process within the explore navigation graph (initiated by
-     * [exploreNavigateTo]) was completed.
-     */
-    fun finishExploreNavigation() {
-        logD("Finishing explore navigation process")
-        _exploreNavigationItem.value = null
-        _exploreArtistNavigationItem.value = null
-    }
 }
 
 /**

app/src/main/java/org/oxycblt/auxio/util/StateUtil.kt

@@ -28,17 +28,40 @@ import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.launch
 
+/**
+ * A wrapper around [StateFlow] exposing a one-time consumable event.
+ *
+ * @author Alexander Capehart (OxygenCobalt)
+ */
 interface Event<T> {
+    /** The inner [StateFlow] contained by the [Event]. */
     val flow: StateFlow<T?>
+    /**
+     * Consume whatever value is currently contained by this instance.
+     *
+     * @return A value placed into this instance prior, or null if there isn't any.
+     */
     fun consume(): T?
 }
 
+/**
+ * A wrapper around [StateFlow] exposing a one-time consumable event that can be modified by it's
+ * owner.
+ *
+ * @author Alexander Capehart (OxygenCobalt)
+ */
 class MutableEvent<T> : Event<T> {
     override val flow = MutableStateFlow<T?>(null)
+    override fun consume() = flow.value?.also { flow.value = null }
+
+    /**
+     * Place a new value into this instance, replacing any prior value.
+     *
+     * @param v The value to update with.
+     */
     fun put(v: T) {
         flow.value = v
     }
-    override fun consume() = flow.value?.also { flow.value = null }
 }
 
 /**