restore scroll position when navigating back to Album and Playlist pages

ui/browsing/albumpage.go

@@ -37,6 +37,7 @@ type AlbumPage struct {
 type albumPageState struct {
 	albumID string
 	sort    widgets.TracklistSort
+	scroll  float32
 	cfg     *backend.AlbumPageConfig
 	pool    *util.WidgetPool
 	mp      mediaprovider.MediaProvider
@@ -54,7 +55,7 @@ func NewAlbumPage(
 	im *backend.ImageManager,
 	contr *controller.Controller,
 ) *AlbumPage {
-	return newAlbumPage(albumID, cfg, pool, pm, mp, im, contr, widgets.TracklistSort{})
+	return newAlbumPage(albumID, cfg, pool, pm, mp, im, contr, widgets.TracklistSort{}, 0)
 }
 
 func newAlbumPage(
@@ -66,6 +67,7 @@ func newAlbumPage(
 	im *backend.ImageManager,
 	contr *controller.Controller,
 	sort widgets.TracklistSort,
+	scroll float32,
 ) *AlbumPage {
 	a := &AlbumPage{
 		albumPageState: albumPageState{
@@ -76,6 +78,7 @@ func newAlbumPage(
 			mp:      mp,
 			im:      im,
 			contr:   contr,
+			scroll:  scroll,
 		},
 	}
 	a.ExtendBaseWidget(a)
@@ -122,6 +125,7 @@ func (a *AlbumPage) Save() SavedPage {
 	a.tracklist.SetLoading(false)
 	s := a.albumPageState
 	s.sort = a.tracklist.Sorting()
+	s.scroll = a.tracklist.GetScrollOffset()
 	a.header.page = nil
 	a.pool.Release(util.WidgetTypeAlbumPageHeader, a.header)
 	a.tracklist.Clear()
@@ -159,7 +163,7 @@ func (a *AlbumPage) UnselectAll() {
 var _ Scrollable = (*AlbumPage)(nil)
 
 func (a *AlbumPage) Scroll(scrollAmt float32) {
-	a.tracklist.Scroll(scrollAmt)
+	a.tracklist.ScrollBy(scrollAmt)
 }
 
 // should be called asynchronously
@@ -188,6 +192,10 @@ func (a *AlbumPage) load() {
 		a.tracks = album.Tracks
 		a.tracklist.SetTracks(album.Tracks)
 		a.tracklist.SetNowPlaying(a.nowPlayingID)
+		if a.scroll != 0 {
+			a.tracklist.ScrollToOffset(a.scroll)
+			a.scroll = 0
+		}
 	})
 }
 
@@ -396,5 +404,5 @@ func formatMiscLabelStr(a *mediaprovider.AlbumWithTracks) string {
 }
 
 func (s *albumPageState) Restore() Page {
-	return newAlbumPage(s.albumID, s.cfg, s.pool, s.pm, s.mp, s.im, s.contr, s.sort)
+	return newAlbumPage(s.albumID, s.cfg, s.pool, s.pm, s.mp, s.im, s.contr, s.sort, s.scroll)
 }

ui/browsing/favoritespage.go

@@ -175,7 +175,7 @@ func (a *FavoritesPage) Scroll(amount float32) {
 		grid = a.artistGrid
 	default:
 		if tr := a.tracklistOrNil(); tr != nil {
-			tr.Scroll(amount)
+			tr.ScrollBy(amount)
 		}
 		return
 	}

ui/browsing/playlistpage.go

@@ -46,6 +46,7 @@ type playlistPageState struct {
 	pm         *backend.PlaybackManager
 	im         *backend.ImageManager
 	trackSort  widgets.TracklistSort
+	scroll     float32
 }
 
 func NewPlaylistPage(
@@ -57,7 +58,7 @@ func NewPlaylistPage(
 	pm *backend.PlaybackManager,
 	im *backend.ImageManager,
 ) *PlaylistPage {
-	return newPlaylistPage(playlistID, conf, contr, pool, sm, pm, im, widgets.TracklistSort{})
+	return newPlaylistPage(playlistID, conf, contr, pool, sm, pm, im, widgets.TracklistSort{}, 0)
 }
 
 func newPlaylistPage(
@@ -69,8 +70,9 @@ func newPlaylistPage(
 	pm *backend.PlaybackManager,
 	im *backend.ImageManager,
 	trackSort widgets.TracklistSort,
+	scroll float32,
 ) *PlaylistPage {
-	a := &PlaylistPage{playlistPageState: playlistPageState{playlistID: playlistID, conf: conf, contr: contr, widgetPool: pool, sm: sm, pm: pm, im: im}}
+	a := &PlaylistPage{playlistPageState: playlistPageState{playlistID: playlistID, conf: conf, contr: contr, widgetPool: pool, sm: sm, pm: pm, im: im, scroll: scroll}}
 	a.ExtendBaseWidget(a)
 	if h := a.widgetPool.Obtain(util.WidgetTypePlaylistPageHeader); h != nil {
 		a.header = h.(*PlaylistPageHeader)
@@ -123,6 +125,7 @@ func (a *PlaylistPage) Save() SavedPage {
 	a.tracklist.SetLoading(false)
 	p := a.playlistPageState
 	p.trackSort = a.tracklist.Sorting()
+	p.scroll = a.tracklist.GetScrollOffset()
 	p.widgetPool.Release(util.WidgetTypePlaylistPageHeader, a.header)
 	a.tracklist.Clear()
 	a.tracklist.OnReorderTracks = nil
@@ -160,7 +163,7 @@ func (a *PlaylistPage) UnselectAll() {
 var _ Scrollable = (*PlaylistPage)(nil)
 
 func (a *PlaylistPage) Scroll(scrollAmt float32) {
-	a.tracklist.Scroll(scrollAmt)
+	a.tracklist.ScrollBy(scrollAmt)
 }
 
 // should be called asynchronously
@@ -188,6 +191,10 @@ func (a *PlaylistPage) load() {
 		a.tracks = playlist.Tracks
 		a.tracklist.SetTracks(playlist.Tracks)
 		a.tracklist.SetNowPlaying(a.nowPlayingID)
+		if a.scroll != 0 {
+			a.tracklist.ScrollToOffset(a.scroll)
+			a.scroll = 0
+		}
 		a.header.Update(playlist)
 	})
 }
@@ -495,5 +502,5 @@ func (a *PlaylistPageHeader) formatPlaylistTrackTimeStr(p *mediaprovider.Playlis
 }
 
 func (s *playlistPageState) Restore() Page {
-	return newPlaylistPage(s.playlistID, s.conf, s.contr, s.widgetPool, s.sm, s.pm, s.im, s.trackSort)
+	return newPlaylistPage(s.playlistID, s.conf, s.contr, s.widgetPool, s.sm, s.pm, s.im, s.trackSort, s.scroll)
 }

ui/browsing/trackspage.go

@@ -128,7 +128,7 @@ func (t *TracksPage) OnSongChange(item mediaprovider.MediaItem, lastScrobbledIfA
 var _ Scrollable = (*TracksPage)(nil)
 
 func (g *TracksPage) Scroll(scrollAmt float32) {
-	g.tracklist.Scroll(scrollAmt)
+	g.tracklist.ScrollBy(scrollAmt)
 }
 
 var _ Searchable = (*TracksPage)(nil)

ui/widgets/tracklist.go

@@ -215,10 +215,18 @@ func (t *Tracklist) SetLoading(loading bool) {
 	}
 }
 
-func (t *Tracklist) Scroll(amount float32) {
+func (t *Tracklist) ScrollBy(amount float32) {
 	t.list.ScrollToOffset(t.list.GetScrollOffset() + amount)
 }
 
+func (t *Tracklist) GetScrollOffset() float32 {
+	return t.list.GetScrollOffset()
+}
+
+func (t *Tracklist) ScrollToOffset(offset float32) {
+	t.list.ScrollToOffset(offset)
+}
+
 // Gets the track at the given index.
 func (t *Tracklist) TrackAt(idx int) *mediaprovider.Track {
 	if idx >= len(t.tracks) {