all: switch to stateflow

Switch from LiveData to StateFlow.

While LiveData is a pretty good data storage/observer mechanism, it has
a few flaws:
- Values are always nullable in LiveData, even if you make them
non-null.
- LiveData can only be mutated on Dispatchers.Main, which frustrates
possible additions like a more fine-grained music status system.
- LiveData's perks are exclusive to ViewModels, which made coupling
with shared objects somewhat cumbersome.

StateFlow solves all of these by being a native coroutine solution with
proper android bindings. Use it instead.

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## dev [v2.3.1, v2.4.0, or v3.0.0]
 
+#### What's Improved
+- Loading UI is now more clear and easy-to-use
+
 #### What's Fixed
 - Fixed crash when seeking to the end of a track as the track changed to a track with a lower duration 
 

app/build.gradle

@@ -22,7 +22,7 @@ android {
     compileSdkVersion 32
     buildToolsVersion "32.0.0"
 
-    // ExoPlayer needs Java 8 to compile.
+    // ExoPlayer, AndroidX, and Material Components all need Java 8 to compile.
 
     compileOptions {
         targetCompatibility JavaVersion.VERSION_1_8
@@ -76,6 +76,7 @@ dependencies {
     implementation "androidx.lifecycle:lifecycle-common-java8:$lifecycle_version"
     implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$lifecycle_version"
     implementation "androidx.lifecycle:lifecycle-livedata-ktx:$lifecycle_version"
+    implementation "androidx.lifecycle:lifecycle-runtime-ktx:$lifecycle_version"
 
     // Navigation
     implementation "androidx.navigation:navigation-ui-ktx:$navigation_version"
@@ -91,7 +92,7 @@ dependencies {
     // --- THIRD PARTY ---
 
     // Exoplayer
-    // WARNING: THE EXOPLAYER VERSION MUST BE KEPT IN LOCK-STEP WITH THE FLAC EXTENSION.
+    // WARNING: THE EXOPLAYER VERSION MUST BE KEPT IN LOCK-STEP WITH THE PRE-BUILD SCRIPT.
     // IF NOT, VERY UNFRIENDLY BUILD FAILURES AND CRASHES MAY ENSUE.
     implementation "com.google.android.exoplayer:exoplayer-core:2.17.1"
     implementation fileTree(dir: "libs", include: ["extension-*.aar"])
@@ -109,7 +110,7 @@ dependencies {
 spotless {
     kotlin {
         target "src/**/*.kt"
-        ktfmt('0.37').dropboxStyle()
+        ktfmt("0.37").dropboxStyle()
         licenseHeaderFile("NOTICE")
     }
 }

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

@@ -22,10 +22,10 @@ import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
 import androidx.activity.OnBackPressedCallback
-import androidx.activity.result.contract.ActivityResultContracts
 import androidx.fragment.app.activityViewModels
 import androidx.navigation.findNavController
 import androidx.navigation.fragment.findNavController
+import kotlinx.coroutines.flow.collect
 import org.oxycblt.auxio.databinding.FragmentMainBinding
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicViewModel
@@ -34,6 +34,7 @@ import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.ui.MainNavigationAction
 import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.ui.ViewBindingFragment
+import org.oxycblt.auxio.util.launch
 
 /**
  * A wrapper around the home fragment that shows the playback fragment and controls the more
@@ -50,12 +51,6 @@ class MainFragment : ViewBindingFragment<FragmentMainBinding>() {
 
     override fun onBindingCreated(binding: FragmentMainBinding, savedInstanceState: Bundle?) {
         // --- UI SETUP ---
-        // Build the permission launcher here as you can only do it in onCreateView/onCreate
-        val permLauncher =
-            registerForActivityResult(ActivityResultContracts.RequestPermission()) {
-                musicModel.reloadMusic(requireContext())
-            }
-
         requireActivity()
             .onBackPressedDispatcher.addCallback(
                 viewLifecycleOwner, DynamicBackPressedCallback().also { callback = it })
@@ -81,10 +76,9 @@ class MainFragment : ViewBindingFragment<FragmentMainBinding>() {
         // TODO: Move this to a service [automatic rescanning]
         musicModel.loadMusic(requireContext())
 
-        navModel.mainNavigationAction.observe(viewLifecycleOwner, ::handleMainNavigation)
+        launch { navModel.mainNavigationAction.collect(::handleMainNavigation) }
-        navModel.exploreNavigationItem.observe(viewLifecycleOwner, ::handleExploreNavigation)
+        launch { navModel.exploreNavigationItem.collect(::handleExploreNavigation) }
-
+        launch { playbackModel.song.collect(::updateSong) }
-        playbackModel.song.observe(viewLifecycleOwner, ::updateSong)
     }
 
     override fun onResume() {

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

@@ -25,6 +25,7 @@ import androidx.core.view.children
 import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
 import androidx.recyclerview.widget.LinearSmoothScroller
+import kotlinx.coroutines.launch
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentDetailBinding
 import org.oxycblt.auxio.detail.recycler.AlbumDetailAdapter
@@ -39,6 +40,7 @@ import org.oxycblt.auxio.ui.Item
 import org.oxycblt.auxio.ui.newMenu
 import org.oxycblt.auxio.util.applySpans
 import org.oxycblt.auxio.util.canScroll
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.logW
 import org.oxycblt.auxio.util.showToast
@@ -66,9 +68,9 @@ class AlbumDetailFragment : DetailFragment(), AlbumDetailAdapter.Listener {
 
         // -- VIEWMODEL SETUP ---
 
-        detailModel.albumData.observe(viewLifecycleOwner, detailAdapter.data::submitList)
+        launch { detailModel.albumData.collect(detailAdapter.data::submitList) }
-        navModel.exploreNavigationItem.observe(viewLifecycleOwner, ::handleNavigation)
+        launch { navModel.exploreNavigationItem.collect(::handleNavigation) }
-        playbackModel.song.observe(viewLifecycleOwner, ::updateSong)
+        launch { playbackModel.song.collect(::updateSong) }
     }
 
     override fun onMenuItemClick(item: MenuItem): Boolean {

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

@@ -22,6 +22,7 @@ import android.view.MenuItem
 import android.view.View
 import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
+import kotlinx.coroutines.launch
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentDetailBinding
 import org.oxycblt.auxio.detail.recycler.ArtistDetailAdapter
@@ -37,6 +38,7 @@ import org.oxycblt.auxio.ui.Header
 import org.oxycblt.auxio.ui.Item
 import org.oxycblt.auxio.ui.newMenu
 import org.oxycblt.auxio.util.applySpans
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.logW
 import org.oxycblt.auxio.util.unlikelyToBeNull
@@ -64,10 +66,10 @@ class ArtistDetailFragment : DetailFragment(), DetailAdapter.Listener {
 
         // --- VIEWMODEL SETUP ---
 
-        detailModel.artistData.observe(viewLifecycleOwner, detailAdapter.data::submitList)
+        launch { detailModel.artistData.collect(detailAdapter.data::submitList) }
-        navModel.exploreNavigationItem.observe(viewLifecycleOwner, ::handleNavigation)
+        launch { navModel.exploreNavigationItem.collect(::handleNavigation) }
-        playbackModel.song.observe(viewLifecycleOwner, ::updateSong)
+        launch { playbackModel.song.collect(::updateSong) }
-        playbackModel.parent.observe(viewLifecycleOwner, ::updateParent)
+        launch { playbackModel.parent.collect(::updateParent) }
     }
 
     override fun onMenuItemClick(item: MenuItem): Boolean = false

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

@@ -17,9 +17,9 @@
  
 package org.oxycblt.auxio.detail
 
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.detail.recycler.DiscHeader
 import org.oxycblt.auxio.detail.recycler.SortHeader
@@ -45,12 +45,12 @@ class DetailViewModel : ViewModel() {
     private val musicStore = MusicStore.getInstance()
     private val settingsManager = SettingsManager.getInstance()
 
-    private val _currentAlbum = MutableLiveData<Album?>()
+    private val _currentAlbum = MutableStateFlow<Album?>(null)
-    val currentAlbum: LiveData<Album?>
+    val currentAlbum: StateFlow<Album?>
         get() = _currentAlbum
 
-    private val _albumData = MutableLiveData(listOf<Item>())
+    private val _albumData = MutableStateFlow(listOf<Item>())
-    val albumData: LiveData<List<Item>>
+    val albumData: StateFlow<List<Item>>
         get() = _albumData
 
     var albumSort: Sort
@@ -60,12 +60,12 @@ class DetailViewModel : ViewModel() {
             currentAlbum.value?.let(::refreshAlbumData)
         }
 
-    private val _currentArtist = MutableLiveData<Artist?>()
+    private val _currentArtist = MutableStateFlow<Artist?>(null)
-    val currentArtist: LiveData<Artist?>
+    val currentArtist: StateFlow<Artist?>
         get() = _currentArtist
 
-    private val _artistData = MutableLiveData(listOf<Item>())
+    private val _artistData = MutableStateFlow(listOf<Item>())
-    val artistData: LiveData<List<Item>> = _artistData
+    val artistData: StateFlow<List<Item>> = _artistData
 
     var artistSort: Sort
         get() = settingsManager.detailArtistSort
@@ -74,12 +74,12 @@ class DetailViewModel : ViewModel() {
             currentArtist.value?.let(::refreshArtistData)
         }
 
-    private val _currentGenre = MutableLiveData<Genre?>()
+    private val _currentGenre = MutableStateFlow<Genre?>(null)
-    val currentGenre: LiveData<Genre?>
+    val currentGenre: StateFlow<Genre?>
         get() = _currentGenre
 
-    private val _genreData = MutableLiveData(listOf<Item>())
+    private val _genreData = MutableStateFlow(listOf<Item>())
-    val genreData: LiveData<List<Item>> = _genreData
+    val genreData: StateFlow<List<Item>> = _genreData
 
     var genreSort: Sort
         get() = settingsManager.detailGenreSort

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

@@ -22,6 +22,7 @@ import android.view.MenuItem
 import android.view.View
 import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
+import kotlinx.coroutines.launch
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentDetailBinding
 import org.oxycblt.auxio.detail.recycler.DetailAdapter
@@ -37,6 +38,7 @@ import org.oxycblt.auxio.ui.Header
 import org.oxycblt.auxio.ui.Item
 import org.oxycblt.auxio.ui.newMenu
 import org.oxycblt.auxio.util.applySpans
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.unlikelyToBeNull
 
@@ -62,9 +64,9 @@ class GenreDetailFragment : DetailFragment(), DetailAdapter.Listener {
 
         // --- VIEWMODEL SETUP ---
 
-        detailModel.genreData.observe(viewLifecycleOwner, detailAdapter.data::submitList)
+        launch { detailModel.genreData.collect(detailAdapter.data::submitList) }
-        navModel.exploreNavigationItem.observe(viewLifecycleOwner, ::handleNavigation)
+        launch { navModel.exploreNavigationItem.collect(::handleNavigation) }
-        playbackModel.song.observe(viewLifecycleOwner, ::updateSong)
+        launch { playbackModel.song.collect(::updateSong) }
     }
 
     override fun onMenuItemClick(item: MenuItem): Boolean = false

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

@@ -35,6 +35,7 @@ import androidx.recyclerview.widget.RecyclerView
 import androidx.viewpager2.adapter.FragmentStateAdapter
 import androidx.viewpager2.widget.ViewPager2
 import com.google.android.material.tabs.TabLayoutMediator
+import kotlinx.coroutines.launch
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentHomeBinding
 import org.oxycblt.auxio.home.list.AlbumListFragment
@@ -53,6 +54,7 @@ import org.oxycblt.auxio.ui.DisplayMode
 import org.oxycblt.auxio.ui.MainNavigationAction
 import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.ui.ViewBindingFragment
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.logE
 import org.oxycblt.auxio.util.logTraceOrThrow
@@ -71,13 +73,14 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
     private val homeModel: HomeViewModel by activityViewModels()
     private val musicModel: MusicViewModel by activityViewModels()
 
+    private var storagePermissionLauncher: ActivityResultLauncher<String>? = null
+    private var sortItem: MenuItem? = null
+
     override fun onCreateBinding(inflater: LayoutInflater) = FragmentHomeBinding.inflate(inflater)
 
     override fun onBindingCreated(binding: FragmentHomeBinding, savedInstanceState: Bundle?) {
-        val sortItem: MenuItem
-
         // Build the permission launcher here as you can only do it in onCreateView/onCreate
-        val permLauncher =
+        storagePermissionLauncher =
             registerForActivityResult(ActivityResultContracts.RequestPermission()) {
                 musicModel.reloadMusic(requireContext())
             }
@@ -89,8 +92,8 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
 
         updateTabConfiguration()
 
-        binding.homeLoadingContainer.setOnApplyWindowInsetsListener { v, insets ->
+        binding.homeLoadingContainer.setOnApplyWindowInsetsListener { view, insets ->
-            v.updatePadding(bottom = insets.systemBarInsetsCompat.bottom)
+            view.updatePadding(bottom = insets.systemBarInsetsCompat.bottom)
             insets
         }
 
@@ -118,20 +121,18 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
 
         // --- VIEWMODEL SETUP ---
 
-        homeModel.isFastScrolling.observe(viewLifecycleOwner, ::updateFastScrolling)
+        launch { homeModel.isFastScrolling.collect(::updateFastScrolling) }
-        homeModel.currentTab.observe(viewLifecycleOwner) { tab -> updateCurrentTab(sortItem, tab) }
+        launch { homeModel.currentTab.collect(::updateCurrentTab) }
-        homeModel.recreateTabs.observe(viewLifecycleOwner, ::handleRecreateTabs)
+        launch { homeModel.recreateTabs.collect(::handleRecreateTabs) }
-
+        launch { musicModel.response.collect(::handleLoaderResponse) }
-        musicModel.loaderResponse.observe(viewLifecycleOwner) { response ->
+        launch { navModel.exploreNavigationItem.collect(::handleNavigation) }
-            handleLoaderResponse(response, permLauncher)
-        }
-
-        navModel.exploreNavigationItem.observe(viewLifecycleOwner, ::handleNavigation)
     }
 
     override fun onDestroyBinding(binding: FragmentHomeBinding) {
         super.onDestroyBinding(binding)
         binding.homeToolbar.setOnMenuItemClickListener(null)
+        storagePermissionLauncher = null
+        sortItem = null
     }
 
     override fun onMenuItemClick(item: MenuItem): Boolean {
@@ -178,7 +179,7 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
 
         // Make sure an update here doesn't mess up the FAB state when it comes to the
         // loader response.
-        if (musicModel.loaderResponse.value !is MusicStore.Response.Ok) {
+        if (musicModel.response.value !is MusicStore.Response.Ok) {
             return
         }
 
@@ -189,21 +190,21 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
         }
     }
 
-    private fun updateCurrentTab(sortItem: MenuItem, tab: DisplayMode) {
+    private fun updateCurrentTab(tab: DisplayMode) {
         // Make sure that we update the scrolling view and allowed menu items whenever
         // the tab changes.
         val binding = requireBinding()
         when (tab) {
             DisplayMode.SHOW_SONGS -> {
-                updateSortMenu(sortItem, tab) { id -> id != R.id.option_sort_count }
+                updateSortMenu(tab) { id -> id != R.id.option_sort_count }
                 binding.homeAppbar.liftOnScrollTargetViewId = R.id.home_song_list
             }
             DisplayMode.SHOW_ALBUMS -> {
-                updateSortMenu(sortItem, tab) { id -> id != R.id.option_sort_album }
+                updateSortMenu(tab) { id -> id != R.id.option_sort_album }
                 binding.homeAppbar.liftOnScrollTargetViewId = R.id.home_album_list
             }
             DisplayMode.SHOW_ARTISTS -> {
-                updateSortMenu(sortItem, tab) { id ->
+                updateSortMenu(tab) { id ->
                     id == R.id.option_sort_asc ||
                         id == R.id.option_sort_name ||
                         id == R.id.option_sort_count ||
@@ -212,7 +213,7 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
                 binding.homeAppbar.liftOnScrollTargetViewId = R.id.home_artist_list
             }
             DisplayMode.SHOW_GENRES -> {
-                updateSortMenu(sortItem, tab) { id ->
+                updateSortMenu(tab) { id ->
                     id == R.id.option_sort_asc ||
                         id == R.id.option_sort_name ||
                         id == R.id.option_sort_count ||
@@ -223,14 +224,13 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
         }
     }
 
-    private fun updateSortMenu(
+    private fun updateSortMenu(displayMode: DisplayMode, isVisible: (Int) -> Boolean) {
-        item: MenuItem,
+        val sortItem =
-        displayMode: DisplayMode,
+            requireNotNull(sortItem) { "Cannot update sort menu when view does not exist" }
-        isVisible: (Int) -> Boolean
+
-    ) {
         val toHighlight = homeModel.getSortForDisplay(displayMode)
 
-        for (option in item.subMenu) {
+        for (option in sortItem.subMenu) {
             if (option.itemId == toHighlight.itemId) {
                 option.isChecked = true
             }
@@ -257,10 +257,7 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
         }
     }
 
-    private fun handleLoaderResponse(
+    private fun handleLoaderResponse(response: MusicStore.Response?) {
-        response: MusicStore.Response?,
-        permLauncher: ActivityResultLauncher<String>
-    ) {
         val binding = requireBinding()
 
         if (response is MusicStore.Response.Ok) {
@@ -296,13 +293,18 @@ class HomeFragment : ViewBindingFragment<FragmentHomeBinding>(), Toolbar.OnMenuI
                     }
                 }
                 is MusicStore.Response.NoPerms -> {
+                    val launcher =
+                        requireNotNull(storagePermissionLauncher) {
+                            "Cannot access permission launcher while in non-view state"
+                        }
+
                     binding.homeLoadingProgress.visibility = View.INVISIBLE
                     binding.homeLoadingStatus.textSafe = getString(R.string.err_no_perms)
                     binding.homeLoadingAction.apply {
                         visibility = View.VISIBLE
                         text = getString(R.string.lbl_grant)
                         setOnClickListener {
-                            permLauncher.launch(Manifest.permission.READ_EXTERNAL_STORAGE)
+                            launcher.launch(Manifest.permission.READ_EXTERNAL_STORAGE)
                         }
                     }
                 }

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

@@ -17,9 +17,9 @@
  
 package org.oxycblt.auxio.home
 
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
 import org.oxycblt.auxio.home.tabs.Tab
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
@@ -40,20 +40,20 @@ class HomeViewModel : ViewModel(), SettingsManager.Callback, MusicStore.Callback
     private val musicStore = MusicStore.getInstance()
     private val settingsManager = SettingsManager.getInstance()
 
-    private val _songs = MutableLiveData(listOf<Song>())
+    private val _songs = MutableStateFlow(listOf<Song>())
-    val songs: LiveData<List<Song>>
+    val songs: StateFlow<List<Song>>
         get() = _songs
 
-    private val _albums = MutableLiveData(listOf<Album>())
+    private val _albums = MutableStateFlow(listOf<Album>())
-    val albums: LiveData<List<Album>>
+    val albums: StateFlow<List<Album>>
         get() = _albums
 
-    private val _artists = MutableLiveData(listOf<Artist>())
+    private val _artists = MutableStateFlow(listOf<Artist>())
-    val artists: LiveData<List<Artist>>
+    val artists: MutableStateFlow<List<Artist>>
         get() = _artists
 
-    private val _genres = MutableLiveData(listOf<Genre>())
+    private val _genres = MutableStateFlow(listOf<Genre>())
-    val genres: LiveData<List<Genre>>
+    val genres: StateFlow<List<Genre>>
         get() = _genres
 
     var tabs: List<DisplayMode> = visibleTabs
@@ -63,18 +63,18 @@ class HomeViewModel : ViewModel(), SettingsManager.Callback, MusicStore.Callback
     private val visibleTabs: List<DisplayMode>
         get() = settingsManager.libTabs.filterIsInstance<Tab.Visible>().map { it.mode }
 
-    private val _currentTab = MutableLiveData(tabs[0])
+    private val _currentTab = MutableStateFlow(tabs[0])
-    val currentTab: LiveData<DisplayMode> = _currentTab
+    val currentTab: StateFlow<DisplayMode> = _currentTab
 
     /**
      * Marker to recreate all library tabs, usually initiated by a settings change. When this flag
      * is set, all tabs (and their respective viewpager fragments) will be recreated from scratch.
      */
-    private val _shouldRecreateTabs = MutableLiveData(false)
+    private val _shouldRecreateTabs = MutableStateFlow(false)
-    val recreateTabs: LiveData<Boolean> = _shouldRecreateTabs
+    val recreateTabs: StateFlow<Boolean> = _shouldRecreateTabs
 
-    private val _isFastScrolling = MutableLiveData(false)
+    private val _isFastScrolling = MutableStateFlow(false)
-    val isFastScrolling: LiveData<Boolean> = _isFastScrolling
+    val isFastScrolling: StateFlow<Boolean> = _isFastScrolling
 
     init {
         musicStore.addCallback(this)
@@ -121,7 +121,6 @@ class HomeViewModel : ViewModel(), SettingsManager.Callback, MusicStore.Callback
                 settingsManager.libGenreSort = sort
                 _genres.value = sort.genres(unlikelyToBeNull(_genres.value))
             }
-            else -> {}
         }
     }
 

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

@@ -17,9 +17,11 @@
  
 package org.oxycblt.auxio.home.list
 
+import android.os.Bundle
 import android.view.View
-import androidx.recyclerview.widget.RecyclerView
+import kotlinx.coroutines.launch
 import org.oxycblt.auxio.R
+import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.ui.AlbumViewHolder
@@ -31,6 +33,7 @@ import org.oxycblt.auxio.ui.PrimitiveBackingData
 import org.oxycblt.auxio.ui.Sort
 import org.oxycblt.auxio.ui.newMenu
 import org.oxycblt.auxio.util.formatDuration
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.unlikelyToBeNull
 
 /**
@@ -40,13 +43,15 @@ import org.oxycblt.auxio.util.unlikelyToBeNull
 class AlbumListFragment : HomeListFragment<Album>() {
     private val homeAdapter = AlbumAdapter(this)
 
-    override fun setupRecycler(recycler: RecyclerView) {
+    override fun onBindingCreated(binding: FragmentHomeListBinding, savedInstanceState: Bundle?) {
-        recycler.apply {
+        super.onBindingCreated(binding, savedInstanceState)
+
+        binding.homeRecycler.apply {
             id = R.id.home_album_list
             adapter = homeAdapter
         }
 
-        homeModel.albums.observe(viewLifecycleOwner) { list -> homeAdapter.data.submitList(list) }
+        launch { homeModel.albums.collect(homeAdapter.data::submitList) }
     }
 
     override fun getPopup(pos: Int): String? {

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

@@ -17,9 +17,11 @@
  
 package org.oxycblt.auxio.home.list
 
+import android.os.Bundle
 import android.view.View
-import androidx.recyclerview.widget.RecyclerView
+import kotlinx.coroutines.launch
 import org.oxycblt.auxio.R
+import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.ui.ArtistViewHolder
@@ -31,6 +33,7 @@ import org.oxycblt.auxio.ui.PrimitiveBackingData
 import org.oxycblt.auxio.ui.Sort
 import org.oxycblt.auxio.ui.newMenu
 import org.oxycblt.auxio.util.formatDuration
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.unlikelyToBeNull
 
 /**
@@ -40,13 +43,15 @@ import org.oxycblt.auxio.util.unlikelyToBeNull
 class ArtistListFragment : HomeListFragment<Artist>() {
     private val homeAdapter = ArtistAdapter(this)
 
-    override fun setupRecycler(recycler: RecyclerView) {
+    override fun onBindingCreated(binding: FragmentHomeListBinding, savedInstanceState: Bundle?) {
-        recycler.apply {
+        super.onBindingCreated(binding, savedInstanceState)
+
+        binding.homeRecycler.apply {
             id = R.id.home_artist_list
             adapter = homeAdapter
         }
 
-        homeModel.artists.observe(viewLifecycleOwner) { list -> homeAdapter.data.submitList(list) }
+        launch { homeModel.artists.collect(homeAdapter.data::submitList) }
     }
 
     override fun getPopup(pos: Int): String? {

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

@@ -17,9 +17,11 @@
  
 package org.oxycblt.auxio.home.list
 
+import android.os.Bundle
 import android.view.View
-import androidx.recyclerview.widget.RecyclerView
+import kotlinx.coroutines.launch
 import org.oxycblt.auxio.R
+import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 import org.oxycblt.auxio.music.Genre
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.ui.DisplayMode
@@ -31,6 +33,7 @@ import org.oxycblt.auxio.ui.PrimitiveBackingData
 import org.oxycblt.auxio.ui.Sort
 import org.oxycblt.auxio.ui.newMenu
 import org.oxycblt.auxio.util.formatDuration
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.unlikelyToBeNull
 
 /**
@@ -40,13 +43,15 @@ import org.oxycblt.auxio.util.unlikelyToBeNull
 class GenreListFragment : HomeListFragment<Genre>() {
     private val homeAdapter = GenreAdapter(this)
 
-    override fun setupRecycler(recycler: RecyclerView) {
+    override fun onBindingCreated(binding: FragmentHomeListBinding, savedInstanceState: Bundle?) {
-        recycler.apply {
+        super.onBindingCreated(binding, savedInstanceState)
+
+        binding.homeRecycler.apply {
             id = R.id.home_genre_list
             adapter = homeAdapter
         }
 
-        homeModel.genres.observe(viewLifecycleOwner) { list -> homeAdapter.data.submitList(list) }
+        launch { homeModel.genres.collect(homeAdapter.data::submitList) }
     }
 
     override fun getPopup(pos: Int): String? {

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

@@ -21,7 +21,6 @@ import android.os.Bundle
 import android.view.LayoutInflater
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.activityViewModels
-import androidx.recyclerview.widget.RecyclerView
 import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 import org.oxycblt.auxio.home.HomeViewModel
 import org.oxycblt.auxio.home.fastscroll.FastScrollRecyclerView
@@ -40,8 +39,6 @@ abstract class HomeListFragment<T : Item> :
     MenuItemListener,
     FastScrollRecyclerView.PopupProvider,
     FastScrollRecyclerView.OnFastScrollListener {
-    abstract fun setupRecycler(recycler: RecyclerView)
-
     protected val playbackModel: PlaybackViewModel by activityViewModels()
     protected val navModel: NavigationViewModel by activityViewModels()
     protected val homeModel: HomeViewModel by activityViewModels()
@@ -50,7 +47,6 @@ abstract class HomeListFragment<T : Item> :
         FragmentHomeListBinding.inflate(inflater)
 
     override fun onBindingCreated(binding: FragmentHomeListBinding, savedInstanceState: Bundle?) {
-        setupRecycler(binding.homeRecycler)
         binding.homeRecycler.popupProvider = this
         binding.homeRecycler.listener = this
     }

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

@@ -17,9 +17,11 @@
  
 package org.oxycblt.auxio.home.list
 
+import android.os.Bundle
 import android.view.View
-import androidx.recyclerview.widget.RecyclerView
+import kotlinx.coroutines.launch
 import org.oxycblt.auxio.R
+import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.ui.DisplayMode
 import org.oxycblt.auxio.ui.Item
@@ -30,6 +32,7 @@ import org.oxycblt.auxio.ui.SongViewHolder
 import org.oxycblt.auxio.ui.Sort
 import org.oxycblt.auxio.ui.newMenu
 import org.oxycblt.auxio.util.formatDuration
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.unlikelyToBeNull
 
 /**
@@ -39,20 +42,22 @@ import org.oxycblt.auxio.util.unlikelyToBeNull
 class SongListFragment : HomeListFragment<Song>() {
     private val homeAdapter = SongsAdapter(this)
 
-    override fun setupRecycler(recycler: RecyclerView) {
+    override fun onBindingCreated(binding: FragmentHomeListBinding, savedInstanceState: Bundle?) {
-        recycler.apply {
+        super.onBindingCreated(binding, savedInstanceState)
+
+        binding.homeRecycler.apply {
             id = R.id.home_song_list
             adapter = homeAdapter
         }
 
-        homeModel.songs.observe(viewLifecycleOwner) { list -> homeAdapter.data.submitList(list) }
+        launch { homeModel.songs.collect(homeAdapter.data::submitList) }
     }
 
     override fun getPopup(pos: Int): String? {
         val song = unlikelyToBeNull(homeModel.songs.value)[pos]
 
         // Change how we display the popup depending on the mode.
-        // We don't use the more correct resolve(Model)Name here, as sorts are largely
+        // Note: We don't use the more correct individual artist name here, as sorts are largely
         // based off the names of the parent objects and not the child objects.
         return when (homeModel.getSortForDisplay(DisplayMode.SHOW_SONGS)) {
             // Name -> Use name

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

@@ -137,6 +137,10 @@ data class Song(
             return result
         }
 
+    /** Internal field. Do not use. */
+    val _genreGroupingId: Long
+        get() = (_genreName ?: MediaStore.UNKNOWN_STRING).hashCode().toLong()
+
     /** Internal field. Do not use. */
     val _artistGroupingName: String?
         get() = _albumArtistName ?: _artistName

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

@@ -74,7 +74,7 @@ class MusicStore private constructor() {
         return newResponse
     }
 
-    private suspend fun loadImpl(context: Context): Response {
+    private fun loadImpl(context: Context): Response {
         val notGranted =
             ContextCompat.checkSelfPermission(context, Manifest.permission.READ_EXTERNAL_STORAGE) ==
                 PackageManager.PERMISSION_DENIED
@@ -110,19 +110,18 @@ class MusicStore private constructor() {
         val albums: List<Album>,
         val songs: List<Song>
     ) {
-        /** Find a song in a faster manner using an ID for its album as well. */
+        /** Find a song in a faster manner by using the album ID as well.. */
-        fun findSongFast(songId: Long, albumId: Long): Song? {
+        fun findSongFast(songId: Long, albumId: Long) =
-            return albums.find { it.id == albumId }?.songs?.find { it.id == songId }
+            albums.find { it.id == albumId }.run { songs.find { it.id == songId } }
-        }
 
         /**
          * Find a song for a [uri], this is similar to [findSongFast], but with some kind of content
          * uri.
          * @return The corresponding [Song] for this [uri], null if there isn't one.
          */
-        fun findSongForUri(context: Context, uri: Uri): Song? {
+        fun findSongForUri(context: Context, uri: Uri) =
-            return context.contentResolverSafe.useQuery(
+            context.contentResolverSafe.useQuery(uri, arrayOf(OpenableColumns.DISPLAY_NAME)) {
-                uri, arrayOf(OpenableColumns.DISPLAY_NAME)) { cursor ->
+                cursor ->
                 cursor.moveToFirst()
 
                 val displayName =
@@ -130,16 +129,11 @@ class MusicStore private constructor() {
 
                 songs.find { it.fileName == displayName }
             }
-        }
     }
 
-    /**
-     * A response that [MusicStore] returns when loading music. And before you ask, yes, I do like
-     * rust.
-     */
     sealed class Response {
-        class Ok(val library: Library) : Response()
+        data class Ok(val library: Library) : Response()
-        class Err(throwable: Throwable) : Response()
+        data class Err(val throwable: Throwable) : Response()
         object NoMusic : Response()
         object NoPerms : Response()
     }

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

@@ -18,42 +18,38 @@
 package org.oxycblt.auxio.music
 
 import android.content.Context
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.launch
 import org.oxycblt.auxio.util.logD
 
 /** A [ViewModel] that represents the current music indexing state. */
-class MusicViewModel : ViewModel(), MusicStore.Callback {
+class MusicViewModel : ViewModel() {
     private val musicStore = MusicStore.getInstance()
 
-    private val _loaderResponse = MutableLiveData<MusicStore.Response?>(null)
+    private val _response = MutableStateFlow<MusicStore.Response?>(null)
-    val loaderResponse: LiveData<MusicStore.Response?> = _loaderResponse
+    val response: StateFlow<MusicStore.Response?> = _response
 
     private var isBusy = false
 
-    init {
-        musicStore.addCallback(this)
-    }
-
     /**
      * Initiate the loading process. This is done here since HomeFragment will be the first fragment
      * navigated to and because SnackBars will have the best UX here.
      */
     fun loadMusic(context: Context) {
-        if (_loaderResponse.value != null || isBusy) {
+        if (_response.value != null || isBusy) {
             logD("Loader is busy/already completed, not reloading")
             return
         }
 
         isBusy = true
-        _loaderResponse.value = null
+        _response.value = null
 
         viewModelScope.launch {
             val result = musicStore.load(context)
-            _loaderResponse.value = result
+            _response.value = result
             isBusy = false
         }
     }
@@ -64,16 +60,7 @@ class MusicViewModel : ViewModel(), MusicStore.Callback {
      */
     fun reloadMusic(context: Context) {
         logD("Reloading music library")
-        _loaderResponse.value = null
+        _response.value = null
         loadMusic(context)
     }
-
-    override fun onMusicUpdate(response: MusicStore.Response) {
-        _loaderResponse.value = response
-    }
-
-    override fun onCleared() {
-        super.onCleared()
-        musicStore.removeCallback(this)
-    }
 }

app/src/main/java/org/oxycblt/auxio/music/excluded/ExcludedDialog.kt

@@ -33,6 +33,7 @@ import org.oxycblt.auxio.databinding.DialogExcludedBinding
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.ui.ViewBindingDialogFragment
 import org.oxycblt.auxio.util.hardRestart
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.logW
 import org.oxycblt.auxio.util.showToast
@@ -92,7 +93,7 @@ class ExcludedDialog :
 
         // --- VIEWMODEL SETUP ---
 
-        excludedModel.paths.observe(viewLifecycleOwner, ::updatePaths)
+        launch { excludedModel.paths.collect(::updatePaths) }
 
         logD("Dialog created")
     }

app/src/main/java/org/oxycblt/auxio/music/excluded/ExcludedViewModel.kt

@@ -18,12 +18,12 @@
 package org.oxycblt.auxio.music.excluded
 
 import android.content.Context
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.viewModelScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import org.oxycblt.auxio.util.logD
@@ -37,8 +37,8 @@ import org.oxycblt.auxio.util.unlikelyToBeNull
  * TODO: Unify with MusicViewModel
  */
 class ExcludedViewModel(private val excludedDatabase: ExcludedDatabase) : ViewModel() {
-    private val _paths = MutableLiveData(mutableListOf<String>())
+    private val _paths = MutableStateFlow(mutableListOf<String>())
-    val paths: LiveData<MutableList<String>>
+    val paths: StateFlow<MutableList<String>>
         get() = _paths
 
     var isModified: Boolean = false

app/src/main/java/org/oxycblt/auxio/music/indexer/ExoPlayerBackend.kt

@@ -91,6 +91,8 @@ class ExoPlayerBackend(private val inner: MediaStoreBackend) : Indexer.Backend {
             // Spin until all tasks are complete
         }
 
+        // TODO: Stabilize sorting order
+
         return songs
     }
 
@@ -124,9 +126,8 @@ class ExoPlayerBackend(private val inner: MediaStoreBackend) : Indexer.Backend {
             // We only support two formats as it stands:
             // - ID3v2 text frames
             // - Vorbis comments
-            // This should be enough to cover the vast, vast majority of audio formats.
+            // TODO: Formats like flac can have both ID3v2 and OGG tags, so we might want to split
-            // It is also assumed that a file only has either ID3v2 text frames or vorbis
+            //  up this logic.
-            // comments.
             when (val tag = metadata.get(i)) {
                 is TextInformationFrame ->
                     if (tag.value.isNotEmpty()) {

app/src/main/java/org/oxycblt/auxio/music/indexer/Indexer.kt

@@ -191,12 +191,16 @@ object Indexer {
         return artists
     }
 
-    /** Build genres and link them to their particular songs. */
+    /**
+     * Group up songs into genres. This is a relatively simple step compared to the other library
+     * steps, as there is no demand to deduplicate genres by a lowercase name.
+     */
     private fun buildGenres(songs: List<Song>): List<Genre> {
         val genres = mutableListOf<Genre>()
-        val songsByGenre = songs.groupBy { it._genreName?.hashCode() }
+        val songsByGenre = songs.groupBy { it._genreGroupingId }
 
         for (entry in songsByGenre) {
+            // The first song fill suffice for template metadata.
             val templateSong = entry.value[0]
             genres.add(Genre(rawName = templateSong._genreName, songs = entry.value))
         }
@@ -214,10 +218,4 @@ object Indexer {
         /** Create a list of songs from the [Cursor] queried in [query]. */
         fun loadSongs(context: Context, cursor: Cursor): Collection<Song>
     }
-
-    sealed class Event {
-        object Query : Event()
-        object LoadSongs : Event()
-        object BuildLibrary : Event()
-    }
 }

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

@@ -28,6 +28,7 @@ import org.oxycblt.auxio.ui.MainNavigationAction
 import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.ui.ViewBindingFragment
 import org.oxycblt.auxio.util.getColorStateListSafe
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.systemGestureInsetsCompat
 import org.oxycblt.auxio.util.textSafe
 
@@ -78,10 +79,9 @@ class PlaybackBarFragment : ViewBindingFragment<FragmentPlaybackBarBinding>() {
 
         // -- VIEWMODEL SETUP ---
 
-        playbackModel.song.observe(viewLifecycleOwner, ::updateSong)
+        launch { playbackModel.song.collect(::updateSong) }
-        playbackModel.isPlaying.observe(viewLifecycleOwner, ::updateIsPlaying)
+        launch { playbackModel.isPlaying.collect(::updateIsPlaying) }
-
+        launch { playbackModel.positionSecs.collect(::updatePosition) }
-        playbackModel.positionSecs.observe(viewLifecycleOwner, ::updatePosition)
     }
 
     private fun updateSong(song: Song?) {

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

@@ -32,6 +32,7 @@ import org.oxycblt.auxio.playback.state.RepeatMode
 import org.oxycblt.auxio.ui.MainNavigationAction
 import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.ui.ViewBindingFragment
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.systemBarInsetsCompat
 import org.oxycblt.auxio.util.textSafe
@@ -52,6 +53,8 @@ class PlaybackPanelFragment :
     private val playbackModel: PlaybackViewModel by activityViewModels()
     private val navModel: NavigationViewModel by activityViewModels()
 
+    private var queueItem: MenuItem? = null
+
     override fun onCreateBinding(inflater: LayoutInflater) =
         FragmentPlaybackPanelBinding.inflate(inflater)
 
@@ -67,8 +70,6 @@ class PlaybackPanelFragment :
             insets
         }
 
-        val queueItem: MenuItem
-
         binding.playbackToolbar.apply {
             setNavigationOnClickListener { navModel.mainNavigateTo(MainNavigationAction.COLLAPSE) }
             setOnMenuItemClickListener(this@PlaybackPanelFragment)
@@ -105,18 +106,13 @@ class PlaybackPanelFragment :
 
         // --- VIEWMODEL SETUP --
 
-        playbackModel.song.observe(viewLifecycleOwner, ::updateSong)
+        launch { playbackModel.song.collect(::updateSong) }
-        playbackModel.parent.observe(viewLifecycleOwner, ::updateParent)
+        launch { playbackModel.parent.collect(::updateParent) }
-        playbackModel.positionSecs.observe(viewLifecycleOwner, ::updatePosition)
+        launch { playbackModel.positionSecs.collect(::updatePosition) }
-        playbackModel.repeatMode.observe(viewLifecycleOwner, ::updateRepeat)
+        launch { playbackModel.repeatMode.collect(::updateRepeat) }
-        playbackModel.isPlaying.observe(viewLifecycleOwner, ::updatePlaying)
+        launch { playbackModel.isPlaying.collect(::updatePlaying) }
-        playbackModel.isShuffled.observe(viewLifecycleOwner, ::updateShuffled)
+        launch { playbackModel.isShuffled.collect(::updateShuffled) }
-
+        launch { playbackModel.nextUp.collect(::updateNextUp) }
-        playbackModel.nextUp.observe(viewLifecycleOwner) { nextUp ->
-            // The queue icon uses a selector that will automatically tint the icon as active or
-            // inactive. We just need to set the flag.
-            queueItem.isEnabled = nextUp.isNotEmpty()
-        }
 
         logD("Fragment Created")
     }
@@ -176,4 +172,9 @@ class PlaybackPanelFragment :
     private fun updateShuffled(isShuffled: Boolean) {
         requireBinding().playbackShuffle.isActivated = isShuffled
     }
+
+    private fun updateNextUp(nextUp: List<Song>) {
+        requireNotNull(queueItem) { "Cannot update next up in non-view state" }.isEnabled =
+            nextUp.isNotEmpty()
+    }
 }

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

@@ -19,10 +19,10 @@ package org.oxycblt.auxio.playback
 
 import android.content.Context
 import android.net.Uri
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.launch
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
@@ -52,32 +52,32 @@ class PlaybackViewModel : ViewModel(), PlaybackStateManager.Callback, MusicStore
 
     private var pendingDelayedAction: DelayedActionImpl? = null
 
-    private val _song = MutableLiveData<Song?>()
+    private val _song = MutableStateFlow<Song?>(null)
     /** The current song. */
-    val song: LiveData<Song?>
+    val song: StateFlow<Song?>
         get() = _song
-    private val _parent = MutableLiveData<MusicParent?>()
+    private val _parent = MutableStateFlow<MusicParent?>(null)
     /** The current model that is being played from, such as an [Album] or [Artist] */
-    val parent: LiveData<MusicParent?>
+    val parent: StateFlow<MusicParent?>
         get() = _parent
-    private val _isPlaying = MutableLiveData(false)
+    private val _isPlaying = MutableStateFlow(false)
-    val isPlaying: LiveData<Boolean>
+    val isPlaying: StateFlow<Boolean>
         get() = _isPlaying
-    private val _positionSecs = MutableLiveData(0L)
+    private val _positionSecs = MutableStateFlow(0L)
     /** The current playback position, in seconds */
-    val positionSecs: LiveData<Long>
+    val positionSecs: StateFlow<Long>
         get() = _positionSecs
-    private val _repeatMode = MutableLiveData(RepeatMode.NONE)
+    private val _repeatMode = MutableStateFlow(RepeatMode.NONE)
     /** The current repeat mode, see [RepeatMode] for more information */
-    val repeatMode: LiveData<RepeatMode>
+    val repeatMode: StateFlow<RepeatMode>
         get() = _repeatMode
-    private val _isShuffled = MutableLiveData(false)
+    private val _isShuffled = MutableStateFlow(false)
-    val isShuffled: LiveData<Boolean>
+    val isShuffled: StateFlow<Boolean>
         get() = _isShuffled
 
-    private val _nextUp = MutableLiveData(listOf<Song>())
+    private val _nextUp = MutableStateFlow(listOf<Song>())
     /** The queue, without the previous items. */
-    val nextUp: LiveData<List<Song>>
+    val nextUp: StateFlow<List<Song>>
         get() = _nextUp
 
     init {

app/src/main/java/org/oxycblt/auxio/playback/queue/QueueFragment.kt

@@ -28,6 +28,7 @@ import org.oxycblt.auxio.databinding.FragmentQueueBinding
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.ui.ViewBindingFragment
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.requireAttached
 
 /**
@@ -52,7 +53,7 @@ class QueueFragment : ViewBindingFragment<FragmentQueueBinding>(), QueueItemList
 
         // --- VIEWMODEL SETUP ----
 
-        playbackModel.nextUp.observe(viewLifecycleOwner, ::updateQueue)
+        launch { playbackModel.nextUp.collect(::updateQueue) }
     }
 
     override fun onDestroyBinding(binding: FragmentQueueBinding) {

app/src/main/java/org/oxycblt/auxio/playback/state/PlaybackStateManager.kt

@@ -331,8 +331,6 @@ class PlaybackStateManager private constructor() {
 
         logD("State read completed successfully in ${System.currentTimeMillis() - start}ms")
 
-        // Get off the IO coroutine since it will cause LiveData updates to throw an exception
-
         if (state != null) {
             index = state.index
             parent = state.parent

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

@@ -30,6 +30,7 @@ import androidx.fragment.app.Fragment
 import androidx.fragment.app.activityViewModels
 import androidx.fragment.app.viewModels
 import androidx.navigation.fragment.findNavController
+import kotlinx.coroutines.launch
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentSearchBinding
 import org.oxycblt.auxio.music.Album
@@ -49,6 +50,7 @@ import org.oxycblt.auxio.ui.ViewBindingFragment
 import org.oxycblt.auxio.ui.newMenu
 import org.oxycblt.auxio.util.applySpans
 import org.oxycblt.auxio.util.getSystemServiceSafe
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.requireAttached
 
 /**
@@ -107,9 +109,9 @@ class SearchFragment :
 
         // --- VIEWMODEL SETUP ---
 
-        searchModel.searchResults.observe(viewLifecycleOwner, ::updateResults)
+        launch { searchModel.searchResults.collect(::updateResults) }
-        navModel.exploreNavigationItem.observe(viewLifecycleOwner, ::handleNavigation)
+        launch { musicModel.response.collect(::handleLoaderResponse) }
-        musicModel.loaderResponse.observe(viewLifecycleOwner, ::handleLoaderResponse)
+        launch { navModel.exploreNavigationItem.collect(::handleNavigation) }
     }
 
     override fun onDestroyBinding(binding: FragmentSearchBinding) {
@@ -144,10 +146,6 @@ class SearchFragment :
     }
 
     private fun updateResults(results: List<Item>) {
-        if (isDetached) {
-            error("Fragment not attached to activity")
-        }
-
         val binding = requireBinding()
 
         searchAdapter.data.submitList(results.toMutableList()) {

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

@@ -19,11 +19,11 @@ package org.oxycblt.auxio.search
 
 import android.content.Context
 import androidx.annotation.IdRes
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import java.text.Normalizer
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.launch
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.music.Music
@@ -43,16 +43,17 @@ class SearchViewModel : ViewModel() {
     private val musicStore = MusicStore.getInstance()
     private val settingsManager = SettingsManager.getInstance()
 
-    private val _searchResults = MutableLiveData(listOf<Item>())
+    private val _searchResults = MutableStateFlow(listOf<Item>())
-    private var _filterMode: DisplayMode? = null
-    private var lastQuery: String? = null
-
     /** Current search results from the last [search] call. */
-    val searchResults: LiveData<List<Item>>
+    val searchResults: StateFlow<List<Item>>
         get() = _searchResults
+
+    private var _filterMode: DisplayMode? = null
     val filterMode: DisplayMode?
         get() = _filterMode
 
+    private var lastQuery: String? = null
+
     init {
         _filterMode = settingsManager.searchFilterMode
     }

app/src/main/java/org/oxycblt/auxio/settings/AboutFragment.kt

@@ -28,12 +28,14 @@ import androidx.core.view.updatePadding
 import androidx.fragment.app.activityViewModels
 import androidx.navigation.fragment.findNavController
 import com.google.android.material.bottomsheet.BottomSheetDialogFragment
+import kotlinx.coroutines.flow.collect
 import org.oxycblt.auxio.BuildConfig
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentAboutBinding
 import org.oxycblt.auxio.home.HomeViewModel
 import org.oxycblt.auxio.ui.ViewBindingFragment
 import org.oxycblt.auxio.util.formatDuration
+import org.oxycblt.auxio.util.launch
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.showToast
 import org.oxycblt.auxio.util.systemBarInsetsCompat
@@ -61,24 +63,37 @@ class AboutFragment : ViewBindingFragment<FragmentAboutBinding>() {
         binding.aboutFaq.setOnClickListener { openLinkInBrowser(LINK_FAQ) }
         binding.aboutLicenses.setOnClickListener { openLinkInBrowser(LINK_LICENSES) }
 
-        homeModel.songs.observe(viewLifecycleOwner) { songs ->
+        launch {
-            binding.aboutSongCount.textSafe = getString(R.string.fmt_songs_loaded, songs.size)
+            homeModel.songs.collect { songs ->
-            binding.aboutTotalDuration.textSafe =
+                binding.aboutSongCount.textSafe = getString(R.string.fmt_songs_loaded, songs.size)
-                getString(
+                binding.aboutTotalDuration.textSafe =
-                    R.string.fmt_total_duration,
+                    getString(
-                    songs.sumOf { it.durationSecs }.formatDuration(false))
+                        R.string.fmt_total_duration,
+                        getString(
+                            R.string.fmt_total_duration,
+                            songs.sumOf { it.durationSecs }.formatDuration(false)))
+            }
         }
 
-        homeModel.albums.observe(viewLifecycleOwner) { albums ->
+        launch {
-            binding.aboutAlbumCount.textSafe = getString(R.string.fmt_albums_loaded, albums.size)
+            homeModel.albums.collect { albums ->
+                binding.aboutAlbumCount.textSafe =
+                    getString(R.string.fmt_albums_loaded, albums.size)
+            }
         }
 
-        homeModel.artists.observe(viewLifecycleOwner) { artists ->
+        launch {
-            binding.aboutArtistCount.textSafe = getString(R.string.fmt_artists_loaded, artists.size)
+            homeModel.artists.collect { artists ->
+                binding.aboutArtistCount.textSafe =
+                    getString(R.string.fmt_artists_loaded, artists.size)
+            }
         }
 
-        homeModel.genres.observe(viewLifecycleOwner) { genres ->
+        launch {
-            binding.aboutGenreCount.textSafe = getString(R.string.fmt_genres_loaded, genres.size)
+            homeModel.genres.collect { genres ->
+                binding.aboutGenreCount.textSafe =
+                    getString(R.string.fmt_genres_loaded, genres.size)
+            }
         }
     }
 

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

@@ -17,9 +17,9 @@
  
 package org.oxycblt.auxio.ui
 
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
 import org.oxycblt.auxio.music.Music
 
 /**
@@ -27,17 +27,17 @@ import org.oxycblt.auxio.music.Music
  * @author OxygenCobalt
  */
 class NavigationViewModel : ViewModel() {
-    private val _mainNavigationAction = MutableLiveData<MainNavigationAction?>()
+    private val _mainNavigationAction = MutableStateFlow<MainNavigationAction?>(null)
     /** Flag for main fragment navigation. Intended for MainFragment use only. */
-    val mainNavigationAction: LiveData<MainNavigationAction?>
+    val mainNavigationAction: StateFlow<MainNavigationAction?>
         get() = _mainNavigationAction
 
-    private val _exploreNavigationItem = MutableLiveData<Music?>()
+    private val _exploreNavigationItem = MutableStateFlow<Music?>(null)
     /**
      * Flag for navigation within the explore fragments. Observe this to coordinate navigation to an
      * item's UI.
      */
-    val exploreNavigationItem: LiveData<Music?>
+    val exploreNavigationItem: StateFlow<Music?>
         get() = _exploreNavigationItem
 
     /** Notify MainFragment to navigate to the location outlined in [MainNavigationAction]. */

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

@@ -31,9 +31,14 @@ import android.widget.TextView
 import androidx.annotation.ColorRes
 import androidx.core.graphics.drawable.DrawableCompat
 import androidx.fragment.app.Fragment
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
 import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import androidx.viewbinding.ViewBinding
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.launch
 import org.oxycblt.auxio.R
 
 /**
@@ -147,6 +152,18 @@ val @receiver:ColorRes Int.stateList
 /** Require the fragment is attached to an activity. */
 fun Fragment.requireAttached() = check(!isDetached) { "Fragment is detached from activity" }
 
+/**
+ * Launches [block] in a lifecycle-aware coroutine once [state] is reached. This is primarily a
+ * shortcut intended to correctly launch a co-routine on a fragment in a way that won't cause
+ * miscellaneous coroutine insanity.
+ */
+fun Fragment.launch(
+    state: Lifecycle.State = Lifecycle.State.STARTED,
+    block: suspend CoroutineScope.() -> Unit
+) {
+    viewLifecycleOwner.lifecycleScope.launch { viewLifecycleOwner.repeatOnLifecycle(state, block) }
+}
+
 /**
  * Shortcut for querying all items in a database and running [block] with the cursor returned. Will
  * not run if the cursor is null.

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

@@ -31,7 +31,6 @@
     <FrameLayout
         android:layout_width="match_parent"
         android:layout_height="match_parent"
-        android:animateLayoutChanges="true"
         app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior">
 
         <androidx.constraintlayout.widget.ConstraintLayout
@@ -40,8 +39,7 @@
             android:layout_height="match_parent"
             android:animateLayoutChanges="true"
             android:paddingStart="@dimen/spacing_medium"
-            android:paddingEnd="@dimen/spacing_medium"
+            android:paddingEnd="@dimen/spacing_medium">
-            tools:visibility="invisible">
 
             <TextView
                 android:id="@+id/home_loading_status"
@@ -70,6 +68,7 @@
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:text="@string/lbl_retry"
+                android:visibility="invisible"
                 app:layout_constraintBottom_toBottomOf="parent"
                 app:layout_constraintTop_toBottomOf="@+id/home_loading_status" />