[Android] Audio: Lazy load providers

[Geoffrey Métais]

vlc-android | branch: master | Geoffrey Métais <geoffrey.metais at gmail.com> | Thu Mar  5 10:32:51 2020 +0100| [4f3d3a7e55012e1a0fb7ee48631893fe404d61d0] | committer: Nicolas Pomepuy

Audio: Lazy load providers

Only load the current items list, load the other ones when we switch to
the related tabs

> https://code.videolan.org/videolan/vlc-android/commit/4f3d3a7e55012e1a0fb7ee48631893fe404d61d0
---

 .../videolan/vlc/gui/audio/AudioBrowserFragment.kt  | 21 +++++++++++----------
 .../vlc/viewmodels/mobile/AudioBrowserViewModel.kt  |  3 +--
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/application/vlc-android/src/org/videolan/vlc/gui/audio/AudioBrowserFragment.kt b/application/vlc-android/src/org/videolan/vlc/gui/audio/AudioBrowserFragment.kt
index 3b14717f8..85c41d028 100644
--- a/application/vlc-android/src/org/videolan/vlc/gui/audio/AudioBrowserFragment.kt
+++ b/application/vlc-android/src/org/videolan/vlc/gui/audio/AudioBrowserFragment.kt
@@ -40,8 +40,6 @@ import com.google.android.material.tabs.TabLayout
 import kotlinx.android.synthetic.main.audio_browser.*
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.ObsoleteCoroutinesApi
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.launch
 import org.videolan.medialibrary.interfaces.media.MediaWrapper
 import org.videolan.medialibrary.media.MediaLibraryItem
 import org.videolan.resources.CTX_PLAY_ALL
@@ -50,13 +48,16 @@ import org.videolan.tools.KEY_ARTISTS_SHOW_ALL
 import org.videolan.tools.RESULT_RESTART
 import org.videolan.tools.Settings
 import org.videolan.vlc.R
-import org.videolan.vlc.gui.*
+import org.videolan.vlc.gui.AudioPlayerContainerActivity
+import org.videolan.vlc.gui.ContentActivity
+import org.videolan.vlc.gui.PlaylistActivity
+import org.videolan.vlc.gui.SecondaryActivity
 import org.videolan.vlc.gui.view.EmptyLoadingState
 import org.videolan.vlc.gui.view.RecyclerSectionItemDecoration
 import org.videolan.vlc.gui.view.RecyclerSectionItemGridDecoration
 import org.videolan.vlc.media.MediaUtils
 import org.videolan.vlc.providers.medialibrary.MedialibraryProvider
-import org.videolan.vlc.util.*
+import org.videolan.vlc.util.getScreenWidth
 import org.videolan.vlc.viewmodels.mobile.AudioBrowserViewModel
 import org.videolan.vlc.viewmodels.mobile.getViewModel
 
@@ -206,13 +207,12 @@ class AudioBrowserFragment : BaseAudioBrowser<AudioBrowserViewModel>() {
         songsAdapter = AudioBrowserAdapter(MediaLibraryItem.TYPE_MEDIA, this, cardSize = if (viewModel.providersInCard[2]) itemSize else -1)
         genresAdapter = AudioBrowserAdapter(MediaLibraryItem.TYPE_GENRE, this)
         adapters = arrayOf(artistsAdapter, albumsAdapter, songsAdapter, genresAdapter)
-        setupProvider(viewModel.providers[currentTab], currentTab)
-            for ((index, provider) in viewModel.providers.withIndex()) {
-                if (index != currentTab) setupProvider(provider, index)
-            }
+        setupProvider()
     }
 
-    private fun setupProvider(provider: MedialibraryProvider<out MediaLibraryItem>, index: Int) {
+    private fun setupProvider(index: Int = viewModel.currentTab) {
+        val provider = viewModel.providers[index]
+        if (provider.loading.hasObservers()) return
         provider.pagedList.observe(viewLifecycleOwner, Observer { items ->
             @Suppress("UNCHECKED_CAST")
             if (items != null) adapters[index].submitList(items as PagedList<MediaLibraryItem>?)
@@ -222,7 +222,7 @@ class AudioBrowserFragment : BaseAudioBrowser<AudioBrowserViewModel>() {
                 restorePositions.delete(index)
             }
         })
-        provider.loading.observe(this, Observer { loading ->
+        provider.loading.observe(viewLifecycleOwner, Observer { loading ->
             if (loading == null || currentTab != index) return at Observer
             setRefreshing(loading)
             if (loading) empty_loading.state = EmptyLoadingState.LOADING
@@ -309,6 +309,7 @@ class AudioBrowserFragment : BaseAudioBrowser<AudioBrowserViewModel>() {
     override fun onTabSelected(tab: TabLayout.Tab) {
         adapter = adapters[tab.position]
         viewModel.currentTab = tab.position
+        setupProvider()
         super.onTabSelected(tab)
         songs_fast_scroller?.setRecyclerView(lists[tab.position], viewModel.providers[tab.position])
         settings.edit().putInt(KEY_AUDIO_CURRENT_TAB, tab.position).apply()
diff --git a/application/vlc-android/src/org/videolan/vlc/viewmodels/mobile/AudioBrowserViewModel.kt b/application/vlc-android/src/org/videolan/vlc/viewmodels/mobile/AudioBrowserViewModel.kt
index 881f0bbca..58530efaf 100644
--- a/application/vlc-android/src/org/videolan/vlc/viewmodels/mobile/AudioBrowserViewModel.kt
+++ b/application/vlc-android/src/org/videolan/vlc/viewmodels/mobile/AudioBrowserViewModel.kt
@@ -38,7 +38,6 @@ import org.videolan.tools.KEY_ARTISTS_SHOW_ALL
 import org.videolan.tools.Settings
 import org.videolan.vlc.viewmodels.MedialibraryViewModel
 
-
 @ExperimentalCoroutinesApi
 class AudioBrowserViewModel(context: Context) : MedialibraryViewModel(context) {
 
@@ -73,7 +72,7 @@ class AudioBrowserViewModel(context: Context) : MedialibraryViewModel(context) {
         viewModelScope.launch {
             providers[currentTab].let { if (!it.isRefreshing) it.awaitRefresh() }
             for ((index, provider) in providers.withIndex()) {
-                if (index != currentTab && !provider.isRefreshing) provider.awaitRefresh()
+                if (index != currentTab && provider.loading.hasObservers() && !provider.isRefreshing) provider.awaitRefresh()
             }
         }
     }