Merge pull request #217 from dweymouth/perf/reuse-widgets

Reuse complex widgets across pages to reduce memory spikes when browsing

ui/browsing/albumpage.go

@@ -25,6 +25,7 @@ type AlbumPage struct {
 
 	albumPageState
 
+	disposed     bool
 	header       *AlbumPageHeader
 	tracks       []*mediaprovider.Track
 	tracklist    *widgets.Tracklist
@@ -36,6 +37,7 @@ type albumPageState struct {
 	albumID string
 	sort    widgets.TracklistSort
 	cfg     *backend.AlbumPageConfig
+	pool    *util.WidgetPool
 	mp      mediaprovider.MediaProvider
 	pm      *backend.PlaybackManager
 	im      *backend.ImageManager
@@ -45,17 +47,19 @@ type albumPageState struct {
 func NewAlbumPage(
 	albumID string,
 	cfg *backend.AlbumPageConfig,
+	pool *util.WidgetPool,
 	pm *backend.PlaybackManager,
 	mp mediaprovider.MediaProvider,
 	im *backend.ImageManager,
 	contr *controller.Controller,
 ) *AlbumPage {
-	return newAlbumPage(albumID, cfg, pm, mp, im, contr, widgets.TracklistSort{})
+	return newAlbumPage(albumID, cfg, pool, pm, mp, im, contr, widgets.TracklistSort{})
 }
 
 func newAlbumPage(
 	albumID string,
 	cfg *backend.AlbumPageConfig,
+	pool *util.WidgetPool,
 	pm *backend.PlaybackManager,
 	mp mediaprovider.MediaProvider,
 	im *backend.ImageManager,
@@ -66,6 +70,7 @@ func newAlbumPage(
 		albumPageState: albumPageState{
 			albumID: albumID,
 			cfg:     cfg,
+			pool:    pool,
 			pm:      pm,
 			mp:      mp,
 			im:      im,
@@ -73,8 +78,20 @@ func newAlbumPage(
 		},
 	}
 	a.ExtendBaseWidget(a)
-	a.header = NewAlbumPageHeader(a)
-	a.tracklist = widgets.NewTracklist(nil)
+	if h := pool.Obtain(util.WidgetTypeAlbumPageHeader); h != nil {
+		a.header = h.(*AlbumPageHeader)
+		a.header.page = a
+		a.header.Clear()
+	} else {
+		a.header = NewAlbumPageHeader(a)
+	}
+	a.header.page = a
+	if t := a.pool.Obtain(util.WidgetTypeTracklist); t != nil {
+		a.tracklist = t.(*widgets.Tracklist)
+		a.tracklist.Reset()
+	} else {
+		a.tracklist = widgets.NewTracklist(nil)
+	}
 	a.tracklist.SetVisibleColumns(a.cfg.TracklistColumns)
 	a.tracklist.SetSorting(sort)
 	a.tracklist.OnVisibleColumnsChanged = func(cols []string) {
@@ -95,8 +112,13 @@ func (a *AlbumPage) CreateRenderer() fyne.WidgetRenderer {
 }
 
 func (a *AlbumPage) Save() SavedPage {
+	a.disposed = true
 	s := a.albumPageState
 	s.sort = a.tracklist.Sorting()
+	a.header.page = nil
+	a.pool.Release(util.WidgetTypeAlbumPageHeader, a.header)
+	a.tracklist.Clear()
+	a.pool.Release(util.WidgetTypeTracklist, a.tracklist)
 	return &s
 }
 
@@ -133,8 +155,13 @@ func (a *AlbumPage) load() {
 		log.Printf("Failed to get album: %s", err.Error())
 		return
 	}
+	if a.disposed {
+		return
+	}
 	a.header.Update(album, a.im)
-	a.tracklist.ShowDiscNumber = album.Tracks[0].DiscNumber != album.Tracks[len(album.Tracks)-1].DiscNumber
+	a.tracklist.Options = widgets.TracklistOptions{
+		ShowDiscNumber: album.Tracks[0].DiscNumber != album.Tracks[len(album.Tracks)-1].DiscNumber,
+	}
 	a.tracks = album.Tracks
 	a.tracklist.SetTracks(album.Tracks)
 	a.tracklist.SetNowPlaying(a.nowPlayingID)
@@ -256,6 +283,19 @@ func (a *AlbumPageHeader) Update(album *mediaprovider.AlbumWithTracks, im *backe
 	}()
 }
 
+func (a *AlbumPageHeader) Clear() {
+	a.albumID = ""
+	a.coverID = ""
+	a.artistID = ""
+	a.titleLabel.Segments[0].(*widget.TextSegment).Text = ""
+	a.artistLabel.SetText("")
+	a.genreLabel.SetText("")
+	a.miscLabel.SetText("")
+	a.toggleFavButton.IsFavorited = false
+	a.cover.Image.Image = nil
+	a.cover.Refresh()
+}
+
 func (a *AlbumPageHeader) toggleFavorited() {
 	params := mediaprovider.RatingFavoriteParameters{AlbumIDs: []string{a.albumID}}
 	a.page.mp.SetFavorite(params, a.toggleFavButton.IsFavorited)
@@ -267,7 +307,9 @@ func (a *AlbumPageHeader) showPopUpCover() {
 		log.Printf("error getting full size album cover: %s", err.Error())
 		return
 	}
-	a.page.contr.ShowPopUpImage(cover)
+	if a.page != nil {
+		a.page.contr.ShowPopUpImage(cover)
+	}
 }
 
 func formatMiscLabelStr(a *mediaprovider.AlbumWithTracks) string {
@@ -283,5 +325,5 @@ func formatMiscLabelStr(a *mediaprovider.AlbumWithTracks) string {
 }
 
 func (s *albumPageState) Restore() Page {
-	return newAlbumPage(s.albumID, s.cfg, 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)
 }

ui/browsing/albumspage.go

@@ -21,20 +21,22 @@ var _ fyne.Widget = (*AlbumsPage)(nil)
 type AlbumsPage struct {
 	widget.BaseWidget
 
-	cfg        *backend.AlbumsPageConfig
-	contr      *controller.Controller
-	pm         *backend.PlaybackManager
-	im         *backend.ImageManager
-	mp         mediaprovider.MediaProvider
-	grid       *widgets.GridView
-	searchGrid *widgets.GridView
-	searcher   *widgets.SearchEntry
-	filterBtn  *widgets.AlbumFilterButton
-	searchText string
-	filter     mediaprovider.AlbumFilter
-	titleDisp  *widget.RichText
-	sortOrder  *selectWidget
-	container  *fyne.Container
+	cfg             *backend.AlbumsPageConfig
+	pool            *util.WidgetPool
+	contr           *controller.Controller
+	pm              *backend.PlaybackManager
+	im              *backend.ImageManager
+	mp              mediaprovider.MediaProvider
+	grid            *widgets.GridView
+	gridState       *widgets.GridViewState
+	searchGridState *widgets.GridViewState
+	searcher        *widgets.SearchEntry
+	filterBtn       *widgets.AlbumFilterButton
+	searchText      string
+	filter          mediaprovider.AlbumFilter
+	titleDisp       *widget.RichText
+	sortOrder       *selectWidget
+	container       *fyne.Container
 }
 
 type selectWidget struct {
@@ -56,8 +58,9 @@ func (s *selectWidget) MinSize() fyne.Size {
 	return fyne.NewSize(170, s.Select.MinSize().Height)
 }
 
-func NewAlbumsPage(cfg *backend.AlbumsPageConfig, contr *controller.Controller, pm *backend.PlaybackManager, mp mediaprovider.MediaProvider, im *backend.ImageManager) *AlbumsPage {
+func NewAlbumsPage(cfg *backend.AlbumsPageConfig, pool *util.WidgetPool, contr *controller.Controller, pm *backend.PlaybackManager, mp mediaprovider.MediaProvider, im *backend.ImageManager) *AlbumsPage {
 	a := &AlbumsPage{
+		pool:  pool,
 		cfg:   cfg,
 		contr: contr,
 		pm:    pm,
@@ -76,10 +79,16 @@ func NewAlbumsPage(cfg *backend.AlbumsPageConfig, contr *controller.Controller,
 	}
 	a.sortOrder.Selected = cfg.SortOrder
 	iter := mp.IterateAlbums(a.sortOrder.Selected, a.filter)
-	a.grid = widgets.NewGridView(widgets.NewGridViewAlbumIterator(iter), im, myTheme.AlbumIcon)
+	if g := pool.Obtain(util.WidgetTypeGridView); g != nil {
+		a.grid = g.(*widgets.GridView)
+		a.grid.Placeholder = myTheme.AlbumIcon
+		a.grid.Reset(widgets.NewGridViewAlbumIterator(iter))
+	} else {
+		a.grid = widgets.NewGridView(widgets.NewGridViewAlbumIterator(iter), im, myTheme.AlbumIcon)
+	}
 	contr.ConnectAlbumGridActions(a.grid)
 	a.createSearchAndFilter()
-	a.createContainer(false)
+	a.createContainer()
 
 	return a
 }
@@ -92,31 +101,30 @@ func (a *AlbumsPage) createSearchAndFilter() {
 	a.filterBtn.OnChanged = a.Reload
 }
 
-func (a *AlbumsPage) createContainer(searchgrid bool) {
+func (a *AlbumsPage) createContainer() {
 	searchVbox := container.NewVBox(layout.NewSpacer(), a.searcher, layout.NewSpacer())
 	sortVbox := container.NewVBox(layout.NewSpacer(), a.sortOrder, layout.NewSpacer())
-	g := a.grid
-	if searchgrid {
-		g = a.searchGrid
-	}
 	a.container = container.NewBorder(
 		container.NewHBox(util.NewHSpace(6), a.titleDisp, sortVbox, layout.NewSpacer(), container.NewCenter(a.filterBtn), searchVbox, util.NewHSpace(12)),
 		nil,
 		nil,
 		nil,
-		g,
+		a.grid,
 	)
 }
 
 func restoreAlbumsPage(saved *savedAlbumsPage) *AlbumsPage {
 	a := &AlbumsPage{
-		cfg:        saved.cfg,
-		contr:      saved.contr,
-		pm:         saved.pm,
-		mp:         saved.mp,
-		im:         saved.im,
-		searchText: saved.searchText,
-		filter:     saved.filter,
+		cfg:             saved.cfg,
+		pool:            saved.pool,
+		contr:           saved.contr,
+		pm:              saved.pm,
+		mp:              saved.mp,
+		im:              saved.im,
+		gridState:       saved.gridState,
+		searchGridState: saved.searchGridState,
+		searchText:      saved.searchText,
+		filter:          saved.filter,
 	}
 	a.ExtendBaseWidget(a)
 
@@ -127,27 +135,33 @@ func restoreAlbumsPage(saved *savedAlbumsPage) *AlbumsPage {
 	a.sortOrder = NewSelect(a.mp.AlbumSortOrders(), nil)
 	a.sortOrder.Selected = saved.sortOrder
 	a.sortOrder.OnChanged = a.onSortOrderChanged
-	a.grid = widgets.NewGridViewFromState(saved.gridState)
+	state := saved.gridState
 	if a.searchText != "" {
-		a.searchGrid = widgets.NewGridViewFromState(saved.searchGridState)
+		a.sortOrder.Disable()
+		state = saved.searchGridState
+	}
+	if g := a.pool.Obtain(util.WidgetTypeGridView); g != nil {
+		a.grid = g.(*widgets.GridView)
+		a.grid.ResetFromState(state)
+	} else {
+		a.grid = widgets.NewGridViewFromState(state)
 	}
 	a.createSearchAndFilter()
-	a.createContainer(saved.searchText != "")
+	a.createContainer()
 
 	return a
 }
 
 func (a *AlbumsPage) OnSearched(query string) {
-	a.searchText = query
 	if query == "" {
-		a.container.Objects[0] = a.grid
-		if a.searchGrid != nil {
-			a.searchGrid.Clear()
-		}
-		a.Refresh()
-		return
+		a.sortOrder.Enable()
+		a.grid.ResetFromState(a.gridState)
+		a.searchGridState = nil
+	} else {
+		a.sortOrder.Disable()
+		a.doSearch(query)
 	}
-	a.doSearch(query)
+	a.searchText = query
 }
 
 func (a *AlbumsPage) Route() controller.Route {
@@ -166,48 +180,45 @@ func (a *AlbumsPage) Reload() {
 	} else {
 		iter := a.mp.IterateAlbums(a.sortOrder.Selected, a.filter)
 		a.grid.Reset(widgets.NewGridViewAlbumIterator(iter))
-		a.grid.Refresh()
 	}
 }
 
 func (a *AlbumsPage) Save() SavedPage {
 	sa := &savedAlbumsPage{
-		cfg:        a.cfg,
-		contr:      a.contr,
-		pm:         a.pm,
-		mp:         a.mp,
-		im:         a.im,
-		searchText: a.searchText,
-		filter:     a.filter,
-		sortOrder:  a.sortOrder.Selected,
-		gridState:  a.grid.SaveToState(),
+		cfg:             a.cfg,
+		pool:            a.pool,
+		contr:           a.contr,
+		pm:              a.pm,
+		mp:              a.mp,
+		im:              a.im,
+		searchText:      a.searchText,
+		filter:          a.filter,
+		sortOrder:       a.sortOrder.Selected,
+		gridState:       a.gridState,
+		searchGridState: a.searchGridState,
 	}
-	if a.searchGrid != nil {
-		sa.searchGridState = a.searchGrid.SaveToState()
+	if a.searchText == "" {
+		sa.gridState = a.grid.SaveToState()
+	} else {
+		sa.searchGridState = a.grid.SaveToState()
 	}
+	a.grid.Clear()
+	a.pool.Release(util.WidgetTypeGridView, a.grid)
 	return sa
 }
 
 func (a *AlbumsPage) doSearch(query string) {
-	iter := widgets.NewGridViewAlbumIterator(a.mp.SearchAlbums(query, a.filter))
-	if a.searchGrid == nil {
-		a.searchGrid = widgets.NewGridView(iter, a.im, myTheme.AlbumIcon)
-		a.contr.ConnectAlbumGridActions(a.searchGrid)
-	} else {
-		a.searchGrid.Reset(iter)
+	if a.searchText == "" {
+		a.gridState = a.grid.SaveToState()
 	}
-	a.container.Objects[0] = a.searchGrid
-	a.Refresh()
+	iter := widgets.NewGridViewAlbumIterator(a.mp.SearchAlbums(query, a.filter))
+	a.grid.Reset(iter)
 }
 
 func (a *AlbumsPage) onSortOrderChanged(order string) {
 	a.cfg.SortOrder = a.sortOrder.Selected
 	iter := a.mp.IterateAlbums(order, a.filter)
 	a.grid.Reset(widgets.NewGridViewAlbumIterator(iter))
-	if a.searchText == "" {
-		a.container.Objects[0] = a.grid
-		a.Refresh()
-	}
 }
 
 func (a *AlbumsPage) CreateRenderer() fyne.WidgetRenderer {
@@ -219,13 +230,14 @@ type savedAlbumsPage struct {
 	searchText      string
 	filter          mediaprovider.AlbumFilter
 	cfg             *backend.AlbumsPageConfig
+	pool            *util.WidgetPool
 	contr           *controller.Controller
 	pm              *backend.PlaybackManager
 	mp              mediaprovider.MediaProvider
 	im              *backend.ImageManager
 	sortOrder       string
-	gridState       widgets.GridViewState
-	searchGridState widgets.GridViewState
+	gridState       *widgets.GridViewState
+	searchGridState *widgets.GridViewState
 }
 
 func (s *savedAlbumsPage) Restore() Page {

ui/browsing/artistpage.go

@@ -28,6 +28,7 @@ type artistPageState struct {
 	activeView int
 	trackSort  widgets.TracklistSort
 
+	pool  *util.WidgetPool
 	cfg   *backend.ArtistPageConfig
 	pm    *backend.PlaybackManager
 	mp    mediaprovider.MediaProvider
@@ -39,6 +40,7 @@ type ArtistPage struct {
 	widget.BaseWidget
 
 	artistPageState
+	disposed bool
 
 	artistInfo *mediaprovider.ArtistWithAlbums
 
@@ -49,18 +51,19 @@ type ArtistPage struct {
 	container    *fyne.Container
 }
 
-func NewArtistPage(artistID string, cfg *backend.ArtistPageConfig, pm *backend.PlaybackManager, mp mediaprovider.MediaProvider, im *backend.ImageManager, contr *controller.Controller) *ArtistPage {
+func NewArtistPage(artistID string, cfg *backend.ArtistPageConfig, pool *util.WidgetPool, pm *backend.PlaybackManager, mp mediaprovider.MediaProvider, im *backend.ImageManager, contr *controller.Controller) *ArtistPage {
 	activeView := 0
 	if cfg.InitialView == "Top Tracks" {
 		activeView = 1
 	}
-	return newArtistPage(artistID, cfg, pm, mp, im, contr, activeView, widgets.TracklistSort{})
+	return newArtistPage(artistID, cfg, pool, pm, mp, im, contr, activeView, widgets.TracklistSort{})
 }
 
-func newArtistPage(artistID string, cfg *backend.ArtistPageConfig, pm *backend.PlaybackManager, mp mediaprovider.MediaProvider, im *backend.ImageManager, contr *controller.Controller, activeView int, sort widgets.TracklistSort) *ArtistPage {
+func newArtistPage(artistID string, cfg *backend.ArtistPageConfig, pool *util.WidgetPool, pm *backend.PlaybackManager, mp mediaprovider.MediaProvider, im *backend.ImageManager, contr *controller.Controller, activeView int, sort widgets.TracklistSort) *ArtistPage {
 	a := &ArtistPage{artistPageState: artistPageState{
 		artistID:   artistID,
 		cfg:        cfg,
+		pool:       pool,
 		pm:         pm,
 		mp:         mp,
 		im:         im,
@@ -69,7 +72,14 @@ func newArtistPage(artistID string, cfg *backend.ArtistPageConfig, pm *backend.P
 		trackSort:  sort,
 	}}
 	a.ExtendBaseWidget(a)
-	a.header = NewArtistPageHeader(a)
+	if h := a.pool.Obtain(util.WidgetTypeArtistPageHeader); h != nil {
+		a.header = h.(*ArtistPageHeader)
+		a.header.artistPage = a
+		a.header.Clear()
+	} else {
+		a.header = NewArtistPageHeader(a)
+	}
+	a.header.artistPage = a
 	if img, ok := im.GetCachedArtistImage(artistID); ok {
 		a.header.artistImage.SetImage(img, true /*tappable*/)
 	}
@@ -112,9 +122,18 @@ func (a *ArtistPage) Reload() {
 }
 
 func (a *ArtistPage) Save() SavedPage {
+	a.disposed = true
 	s := a.artistPageState
 	if a.tracklistCtr != nil {
-		s.trackSort = a.tracklistCtr.Objects[0].(*widgets.Tracklist).Sorting()
+		tl := a.tracklistCtr.Objects[0].(*widgets.Tracklist)
+		s.trackSort = tl.Sorting()
+		tl.Clear()
+		a.pool.Release(util.WidgetTypeTracklist, tl)
+	}
+	a.pool.Release(util.WidgetTypeArtistPageHeader, a.header)
+	if a.albumGrid != nil {
+		a.albumGrid.Clear()
+		a.pool.Release(util.WidgetTypeGridView, a.albumGrid)
 	}
 	return &s
 }
@@ -141,6 +160,9 @@ func (a *ArtistPage) load() {
 		log.Printf("Failed to get artist: %s", err.Error())
 		return
 	}
+	if a.disposed {
+		return
+	}
 	a.artistInfo = artist
 	a.header.Update(artist)
 	if a.activeView == 0 {
@@ -170,7 +192,13 @@ func (a *ArtistPage) showAlbumGrid() {
 				Secondary:  strconv.Itoa(al.Year),
 			}
 		})
-		a.albumGrid = widgets.NewFixedGridView(model, a.im, myTheme.AlbumIcon)
+		if g := a.pool.Obtain(util.WidgetTypeGridView); g != nil {
+			a.albumGrid = g.(*widgets.GridView)
+			a.albumGrid.Placeholder = myTheme.AlbumIcon
+			a.albumGrid.ResetFixed(model)
+		} else {
+			a.albumGrid = widgets.NewFixedGridView(model, a.im, myTheme.AlbumIcon)
+		}
 		a.contr.ConnectAlbumGridActions(a.albumGrid)
 	}
 	a.container.Objects[0].(*fyne.Container).Objects[0] = a.albumGrid
@@ -189,8 +217,18 @@ func (a *ArtistPage) showTopTracks() {
 			log.Printf("error getting top songs: %s", err.Error())
 			return
 		}
-		tl := widgets.NewTracklist(ts)
-		tl.AutoNumber = true
+		if a.disposed {
+			return
+		}
+		var tl *widgets.Tracklist
+		if t := a.pool.Obtain(util.WidgetTypeTracklist); t != nil {
+			tl = t.(*widgets.Tracklist)
+			tl.Reset()
+			tl.SetTracks(ts)
+		} else {
+			tl = widgets.NewTracklist(ts)
+		}
+		tl.Options = widgets.TracklistOptions{AutoNumber: true}
 		tl.SetVisibleColumns(a.cfg.TracklistColumns)
 		tl.SetSorting(a.trackSort)
 		tl.OnVisibleColumnsChanged = func(cols []string) {
@@ -228,9 +266,11 @@ func (a *ArtistPage) CreateRenderer() fyne.WidgetRenderer {
 }
 
 func (s *artistPageState) Restore() Page {
-	return newArtistPage(s.artistID, s.cfg, s.pm, s.mp, s.im, s.contr, s.activeView, s.trackSort)
+	return newArtistPage(s.artistID, s.cfg, s.pool, s.pm, s.mp, s.im, s.contr, s.activeView, s.trackSort)
 }
 
+const artistBioNotAvailableStr = "Artist biography not available."
+
 type ArtistPageHeader struct {
 	widget.BaseWidget
 
@@ -250,7 +290,7 @@ func NewArtistPageHeader(page *ArtistPage) *ArtistPageHeader {
 	a := &ArtistPageHeader{
 		artistPage:     page,
 		titleDisp:      widget.NewRichTextWithText(""),
-		biographyDisp:  widget.NewRichTextWithText("Artist biography not available."),
+		biographyDisp:  widget.NewRichTextWithText(artistBioNotAvailableStr),
 		similarArtists: container.NewHBox(),
 	}
 	a.titleDisp.Segments[0].(*widget.TextSegment).Style = widget.RichTextStyle{
@@ -273,6 +313,17 @@ func NewArtistPageHeader(page *ArtistPage) *ArtistPageHeader {
 	return a
 }
 
+func (a *ArtistPageHeader) Clear() {
+	a.artistID = ""
+	a.favoriteBtn.IsFavorited = false
+	a.titleDisp.Segments[0].(*widget.TextSegment).Text = ""
+	a.biographyDisp.Segments[0].(*widget.TextSegment).Text = artistBioNotAvailableStr
+	for _, obj := range a.similarArtists.Objects {
+		obj.Hide()
+	}
+	a.artistImage.SetImage(nil, false)
+}
+
 func (a *ArtistPageHeader) Update(artist *mediaprovider.ArtistWithAlbums) {
 	if artist == nil {
 		return
@@ -299,21 +350,29 @@ func (a *ArtistPageHeader) UpdateInfo(info *mediaprovider.ArtistInfo) {
 		}
 	}
 
-	a.similarArtists.RemoveAll()
+	if len(a.similarArtists.Objects) == 0 {
+		a.similarArtists.Add(widget.NewLabel("Similar Artists:"))
+	}
+	for _, obj := range a.similarArtists.Objects {
+		obj.Hide()
+	}
 	for i, art := range info.SimilarArtists {
 		if i == 0 {
-			a.similarArtists.Add(widget.NewLabel("Similar Artists:"))
+			a.similarArtists.Objects[0].Show() // "Similar Artists:" label
 		}
 		if i == 4 {
 			break
 		}
-		h := widgets.NewCustomHyperlink()
+		if len(a.similarArtists.Objects) <= i+1 {
+			a.similarArtists.Add(widgets.NewCustomHyperlink())
+		}
+		h := a.similarArtists.Objects[i+1].(*widgets.CustomHyperlink)
 		h.NoTruncate = true
 		h.SetText(art.Name)
 		h.OnTapped = func(id string) func() {
 			return func() { a.artistPage.contr.NavigateTo(controller.ArtistRoute(id)) }
 		}(art.ID)
-		a.similarArtists.Add(h)
+		h.Show()
 	}
 	a.similarArtists.Refresh()
 

ui/browsing/artistspage.go

@@ -23,6 +23,7 @@ type ArtistsPage struct {
 	widget.BaseWidget
 
 	contr               *controller.Controller
+	pool                *util.WidgetPool
 	im                  *backend.ImageManager
 	pm                  *backend.PlaybackManager
 	mp                  mediaprovider.MediaProvider
@@ -40,15 +41,17 @@ type ArtistsPage struct {
 
 func NewArtistsPage(
 	contr *controller.Controller,
+	pool *util.WidgetPool,
 	pm *backend.PlaybackManager,
 	mp mediaprovider.MediaProvider,
 	im *backend.ImageManager,
 ) *ArtistsPage {
-	return newArtistsPage(contr, pm, mp, im, "", 0, 0)
+	return newArtistsPage(contr, pool, pm, mp, im, "", 0, 0)
 }
 
 func newArtistsPage(
 	contr *controller.Controller,
+	pool *util.WidgetPool,
 	pm *backend.PlaybackManager,
 	mp mediaprovider.MediaProvider,
 	im *backend.ImageManager,
@@ -58,6 +61,7 @@ func newArtistsPage(
 ) *ArtistsPage {
 	a := &ArtistsPage{
 		contr:               contr,
+		pool:                pool,
 		pm:                  pm,
 		mp:                  mp,
 		im:                  im,
@@ -74,7 +78,13 @@ func newArtistsPage(
 	a.searcher = widgets.NewSearchEntry()
 	a.searcher.OnSearched = func(query string) { a.onSearched(query, false /*firstLoad*/) }
 	a.searcher.Entry.Text = searchText
-	a.grid = widgets.NewFixedGridView(nil, a.im, myTheme.ArtistIcon)
+	if g := pool.Obtain(util.WidgetTypeGridView); g != nil {
+		a.grid = g.(*widgets.GridView)
+		a.grid.Placeholder = myTheme.ArtistIcon
+		a.grid.Clear()
+	} else {
+		a.grid = widgets.NewFixedGridView(nil, a.im, myTheme.ArtistIcon)
+	}
 	a.contr.ConnectArtistGridActions(a.grid)
 
 	searchVbox := container.NewVBox(layout.NewSpacer(), a.searcher, layout.NewSpacer())
@@ -158,6 +168,7 @@ func (a *ArtistsPage) Route() controller.Route {
 func (a *ArtistsPage) Save() SavedPage {
 	s := &savedArtistsPage{
 		contr:             a.contr,
+		pool:              a.pool,
 		im:                a.im,
 		pm:                a.pm,
 		mp:                a.mp,
@@ -169,11 +180,14 @@ func (a *ArtistsPage) Save() SavedPage {
 	} else {
 		s.searchGridScrollPos = a.grid.GetScrollOffset()
 	}
+	a.grid.Clear()
+	a.pool.Release(util.WidgetTypeGridView, a.grid)
 	return s
 }
 
 type savedArtistsPage struct {
 	contr               *controller.Controller
+	pool                *util.WidgetPool
 	im                  *backend.ImageManager
 	pm                  *backend.PlaybackManager
 	mp                  mediaprovider.MediaProvider
@@ -183,5 +197,5 @@ type savedArtistsPage struct {
 }
 
 func (s *savedArtistsPage) Restore() Page {
-	return newArtistsPage(s.contr, s.pm, s.mp, s.im, s.searchText, s.fullGridScrollPos, s.searchGridScrollPos)
+	return newArtistsPage(s.contr, s.pool, s.pm, s.mp, s.im, s.searchText, s.fullGridScrollPos, s.searchGridScrollPos)
 }

ui/browsing/browsingpane.go

@@ -233,17 +233,21 @@ func (b *BrowsingPane) GoHome() {
 
 func (b *BrowsingPane) GoBack() {
 	if b.historyIdx > 0 {
+		// due to widget reuse between pages,
+		// we must create the new page before calling addPageToHistory
+		p := b.history[b.historyIdx-1].Restore()
 		b.addPageToHistory(b.curPage, false)
 		b.historyIdx -= 2
-		b.doSetPage(b.history[b.historyIdx].Restore())
+		b.doSetPage(p)
 		b.updateHistoryButtons()
 	}
 }
 
 func (b *BrowsingPane) GoForward() {
 	if b.historyIdx < len(b.history)-1 {
+		p := b.history[b.historyIdx+1].Restore()
 		b.addPageToHistory(b.curPage, false)
-		b.doSetPage(b.history[b.historyIdx].Restore())
+		b.doSetPage(p)
 		b.updateHistoryButtons()
 	}
 }

ui/browsing/favoritespage.go

@@ -23,32 +23,36 @@ type FavoritesPage struct {
 	widget.BaseWidget
 
 	cfg   *backend.FavoritesPageConfig
+	pool  *util.WidgetPool
 	contr *controller.Controller
 	pm    *backend.PlaybackManager
 	im    *backend.ImageManager
 	mp    mediaprovider.MediaProvider
 
+	disposed          bool
 	trackSort         widgets.TracklistSort
 	filter            mediaprovider.AlbumFilter
 	searchText        string
 	nowPlayingID      string
 	pendingViewSwitch bool
 
-	grid         *widgets.GridView
-	searchGrid   *widgets.GridView
-	artistGrid   *widgets.GridView
-	tracklistCtr *fyne.Container
-	searcher     *widgets.SearchEntry
-	filterBtn    *widgets.AlbumFilterButton
-	titleDisp    *widget.RichText
-	toggleBtns   *widgets.ToggleButtonGroup
-	container    *fyne.Container
+	grid            *widgets.GridView
+	gridState       *widgets.GridViewState
+	searchGridState *widgets.GridViewState
+	artistGrid      *widgets.GridView
+	tracklistCtr    *fyne.Container
+	searcher        *widgets.SearchEntry
+	filterBtn       *widgets.AlbumFilterButton
+	titleDisp       *widget.RichText
+	toggleBtns      *widgets.ToggleButtonGroup
+	container       *fyne.Container
 }
 
-func NewFavoritesPage(cfg *backend.FavoritesPageConfig, contr *controller.Controller, mp mediaprovider.MediaProvider, pm *backend.PlaybackManager, im *backend.ImageManager) *FavoritesPage {
+func NewFavoritesPage(cfg *backend.FavoritesPageConfig, pool *util.WidgetPool, contr *controller.Controller, mp mediaprovider.MediaProvider, pm *backend.PlaybackManager, im *backend.ImageManager) *FavoritesPage {
 	a := &FavoritesPage{
 		filter: mediaprovider.AlbumFilter{ExcludeUnfavorited: true},
 		cfg:    cfg,
+		pool:   pool,
 		contr:  contr,
 		pm:     pm,
 		mp:     mp,
@@ -56,8 +60,14 @@ func NewFavoritesPage(cfg *backend.FavoritesPageConfig, contr *controller.Contro
 	}
 	a.ExtendBaseWidget(a)
 	a.createHeader(0)
-	iter := mp.IterateAlbums("", a.filter)
-	a.grid = widgets.NewGridView(widgets.NewGridViewAlbumIterator(iter), a.im, myTheme.AlbumIcon)
+	iter := widgets.NewGridViewAlbumIterator(mp.IterateAlbums("", a.filter))
+	if g := pool.Obtain(util.WidgetTypeGridView); g != nil {
+		a.grid = g.(*widgets.GridView)
+		a.grid.Placeholder = myTheme.AlbumIcon
+		a.grid.Reset(iter)
+	} else {
+		a.grid = widgets.NewGridView(iter, a.im, myTheme.AlbumIcon)
+	}
 	a.contr.ConnectAlbumGridActions(a.grid)
 	if cfg.InitialView == "Artists" {
 		a.toggleBtns.SetActivatedButton(1)
@@ -97,21 +107,30 @@ func (a *FavoritesPage) createContainer(initialView fyne.CanvasObject) {
 
 func restoreFavoritesPage(saved *savedFavoritesPage) *FavoritesPage {
 	a := &FavoritesPage{
-		cfg:        saved.cfg,
-		contr:      saved.contr,
-		pm:         saved.pm,
-		mp:         saved.mp,
-		im:         saved.im,
-		searchText: saved.searchText,
-		filter:     saved.filter,
-		trackSort:  saved.trackSort,
+		cfg:             saved.cfg,
+		contr:           saved.contr,
+		pool:            saved.pool,
+		pm:              saved.pm,
+		mp:              saved.mp,
+		im:              saved.im,
+		gridState:       saved.gridState,
+		searchGridState: saved.searchGridState,
+		searchText:      saved.searchText,
+		filter:          saved.filter,
+		trackSort:       saved.trackSort,
 	}
 	a.ExtendBaseWidget(a)
 	a.createHeader(saved.activeToggleBtn)
-	a.grid = widgets.NewGridViewFromState(saved.gridState)
-
+	state := saved.gridState
 	if saved.searchText != "" {
-		a.searchGrid = widgets.NewGridViewFromState(saved.searchGridState)
+		state = saved.searchGridState
+	}
+	if g := a.pool.Obtain(util.WidgetTypeGridView); g != nil {
+		a.grid = g.(*widgets.GridView)
+		a.grid.Placeholder = myTheme.AlbumIcon
+		a.grid.ResetFromState(state)
+	} else {
+		a.grid = widgets.NewGridViewFromState(state)
 	}
 	a.toggleBtns.SetActivatedButton(saved.activeToggleBtn)
 
@@ -119,8 +138,6 @@ func restoreFavoritesPage(saved *savedFavoritesPage) *FavoritesPage {
 		a.onShowFavoriteArtists()
 	} else if saved.activeToggleBtn == 2 {
 		a.onShowFavoriteSongs()
-	} else if saved.searchText != "" {
-		a.createContainer(a.searchGrid)
 	} else {
 		a.createContainer(a.grid)
 	}
@@ -154,6 +171,9 @@ func (a *FavoritesPage) Reload() {
 				log.Printf("error getting starred items: %s", err.Error())
 				return
 			}
+			if a.disposed {
+				return
+			}
 			if a.tracklistCtr != nil {
 				// refresh favorite songs view
 				tr := a.tracklistCtr.Objects[0].(*widgets.Tracklist)
@@ -176,22 +196,36 @@ func (a *FavoritesPage) Reload() {
 }
 
 func (a *FavoritesPage) Save() SavedPage {
+	a.disposed = true
 	sf := &savedFavoritesPage{
 		cfg:             a.cfg,
 		contr:           a.contr,
+		pool:            a.pool,
 		pm:              a.pm,
 		mp:              a.mp,
 		im:              a.im,
 		filter:          a.filter,
 		searchText:      a.searchText,
-		gridState:       a.grid.SaveToState(),
+		gridState:       a.gridState,
+		searchGridState: a.searchGridState,
 		activeToggleBtn: a.toggleBtns.ActivatedButtonIndex(),
 	}
-	if a.searchGrid != nil {
-		sf.searchGridState = a.searchGrid.SaveToState()
+	if a.searchText != "" {
+		sf.searchGridState = a.grid.SaveToState()
+	} else {
+		sf.gridState = a.grid.SaveToState()
+	}
+	a.grid.Clear()
+	a.pool.Release(util.WidgetTypeGridView, a.grid)
+	if a.artistGrid != nil {
+		a.artistGrid.Clear()
+		a.pool.Release(util.WidgetTypeGridView, a.artistGrid)
 	}
 	if a.tracklistCtr != nil {
-		sf.trackSort = a.tracklistCtr.Objects[0].(*widgets.Tracklist).Sorting()
+		tl := a.tracklistCtr.Objects[0].(*widgets.Tracklist)
+		sf.trackSort = tl.Sorting()
+		tl.Clear()
+		a.pool.Release(util.WidgetTypeTracklist, tl)
 	}
 	return sf
 }
@@ -203,16 +237,13 @@ func (a *FavoritesPage) SearchWidget() fyne.Focusable {
 }
 
 func (a *FavoritesPage) OnSearched(query string) {
-	a.searchText = query
 	if query == "" {
-		a.container.Objects[0] = a.grid
-		if a.searchGrid != nil {
-			a.searchGrid.Clear()
-		}
-		a.Refresh()
-		return
+		a.grid.ResetFromState(a.gridState)
+		a.searchGridState = nil
+	} else {
+		a.doSearchAlbums(query)
 	}
-	a.doSearchAlbums(query)
+	a.searchText = query
 }
 
 var _ CanShowNowPlaying = (*FavoritesPage)(nil)
@@ -236,26 +267,18 @@ func (a *FavoritesPage) SelectAll() {
 }
 
 func (a *FavoritesPage) doSearchAlbums(query string) {
-	iter := a.mp.SearchAlbums(query, a.filter)
-	if a.searchGrid == nil {
-		a.searchGrid = widgets.NewGridView(widgets.NewGridViewAlbumIterator(iter), a.im, myTheme.AlbumIcon)
-		a.contr.ConnectAlbumGridActions(a.searchGrid)
-	} else {
-		a.searchGrid.Reset(widgets.NewGridViewAlbumIterator(iter))
+	if a.searchText == "" {
+		a.gridState = a.grid.SaveToState()
 	}
-	a.container.Objects[0] = a.searchGrid
-	a.Refresh()
+	iter := widgets.NewGridViewAlbumIterator(a.mp.SearchAlbums(query, a.filter))
+	a.grid.Reset(iter)
 }
 
 func (a *FavoritesPage) onShowFavoriteAlbums() {
 	a.cfg.InitialView = "Albums" // save setting
 	a.searcher.Entry.Show()
 	a.filterBtn.Show()
-	if a.searchText == "" {
-		a.container.Objects[0] = a.grid
-	} else {
-		a.container.Objects[0] = a.searchGrid
-	}
+	a.container.Objects[0] = a.grid
 	a.Refresh()
 }
 
@@ -277,8 +300,17 @@ func (a *FavoritesPage) onShowFavoriteArtists() {
 				log.Printf("error getting starred items: %s", err.Error())
 				return
 			}
+			if a.disposed {
+				return
+			}
 			model := buildArtistGridViewModel(fav.Artists)
-			a.artistGrid = widgets.NewFixedGridView(model, a.im, myTheme.ArtistIcon)
+			if g := a.pool.Obtain(util.WidgetTypeGridView); g != nil {
+				a.artistGrid = g.(*widgets.GridView)
+				a.artistGrid.Placeholder = myTheme.ArtistIcon
+				a.artistGrid.ResetFixed(model)
+			} else {
+				a.artistGrid = widgets.NewFixedGridView(model, a.im, myTheme.ArtistIcon)
+			}
 			a.contr.ConnectArtistGridActions(a.artistGrid)
 			a.container.Objects[0] = a.artistGrid
 			a.Refresh()
@@ -325,8 +357,18 @@ func (a *FavoritesPage) onShowFavoriteSongs() {
 				log.Printf("error getting starred items: %s", err.Error())
 				return
 			}
-			tracklist := widgets.NewTracklist(fav.Tracks)
-			tracklist.AutoNumber = true
+			if a.disposed {
+				return
+			}
+			var tracklist *widgets.Tracklist
+			if tl := a.pool.Obtain(util.WidgetTypeTracklist); tl != nil {
+				tracklist = tl.(*widgets.Tracklist)
+				tracklist.Reset()
+				tracklist.SetTracks(fav.Tracks)
+			} else {
+				tracklist = widgets.NewTracklist(fav.Tracks)
+			}
+			tracklist.Options = widgets.TracklistOptions{AutoNumber: true}
 			tracklist.SetVisibleColumns(a.cfg.TracklistColumns)
 			tracklist.SetSorting(a.trackSort)
 			tracklist.OnVisibleColumnsChanged = func(cols []string) {
@@ -355,11 +397,12 @@ func (a *FavoritesPage) CreateRenderer() fyne.WidgetRenderer {
 type savedFavoritesPage struct {
 	cfg             *backend.FavoritesPageConfig
 	contr           *controller.Controller
+	pool            *util.WidgetPool
 	pm              *backend.PlaybackManager
 	mp              mediaprovider.MediaProvider
 	im              *backend.ImageManager
-	gridState       widgets.GridViewState
-	searchGridState widgets.GridViewState
+	gridState       *widgets.GridViewState
+	searchGridState *widgets.GridViewState
 	filter          mediaprovider.AlbumFilter
 	searchText      string
 	activeToggleBtn int

ui/browsing/genrepage.go

@@ -19,26 +19,29 @@ import (
 type GenrePage struct {
 	widget.BaseWidget
 
-	genre      string
-	contr      *controller.Controller
-	im         *backend.ImageManager
-	pm         *backend.PlaybackManager
-	mp         mediaprovider.MediaProvider
-	grid       *widgets.GridView
-	searchGrid *widgets.GridView
-	searcher   *widgets.SearchEntry
-	searchText string
-	filter     mediaprovider.AlbumFilter
-	filterBtn  *widgets.AlbumFilterButton
-	titleDisp  *widget.RichText
-	playRandom *widget.Button
+	genre           string
+	pool            *util.WidgetPool
+	contr           *controller.Controller
+	im              *backend.ImageManager
+	pm              *backend.PlaybackManager
+	mp              mediaprovider.MediaProvider
+	grid            *widgets.GridView
+	gridState       *widgets.GridViewState
+	searchGridState *widgets.GridViewState
+	searcher        *widgets.SearchEntry
+	searchText      string
+	filter          mediaprovider.AlbumFilter
+	filterBtn       *widgets.AlbumFilterButton
+	titleDisp       *widget.RichText
+	playRandom      *widget.Button
 
 	container *fyne.Container
 }
 
-func NewGenrePage(genre string, contr *controller.Controller, pm *backend.PlaybackManager, mp mediaprovider.MediaProvider, im *backend.ImageManager) *GenrePage {
+func NewGenrePage(genre string, pool *util.WidgetPool, contr *controller.Controller, pm *backend.PlaybackManager, mp mediaprovider.MediaProvider, im *backend.ImageManager) *GenrePage {
 	g := &GenrePage{
 		genre:  genre,
+		pool:   pool,
 		filter: mediaprovider.AlbumFilter{Genres: []string{genre}},
 		contr:  contr,
 		pm:     pm,
@@ -52,11 +55,17 @@ func NewGenrePage(genre string, contr *controller.Controller, pm *backend.Playba
 		SizeName: theme.SizeNameHeadingText,
 	}
 	g.playRandom = widget.NewButtonWithIcon(" Play random", myTheme.ShuffleIcon, g.playRandomSongs)
-	iter := g.mp.IterateAlbums("", g.filter)
-	g.grid = widgets.NewGridView(widgets.NewGridViewAlbumIterator(iter), g.im, myTheme.AlbumIcon)
+	iter := widgets.NewGridViewAlbumIterator(g.mp.IterateAlbums("", g.filter))
+	if gv := pool.Obtain(util.WidgetTypeGridView); gv != nil {
+		g.grid = gv.(*widgets.GridView)
+		g.grid.Placeholder = myTheme.AlbumIcon
+		g.grid.Reset(iter)
+	} else {
+		g.grid = widgets.NewGridView(iter, g.im, myTheme.AlbumIcon)
+	}
 	g.contr.ConnectAlbumGridActions(g.grid)
 	g.createSearchAndFilter()
-	g.createContainer(false)
+	g.createContainer()
 
 	return g
 }
@@ -71,29 +80,28 @@ func (g *GenrePage) createSearchAndFilter() {
 	g.filterBtn.OnChanged = g.Reload
 }
 
-func (g *GenrePage) createContainer(searchGrid bool) {
+func (g *GenrePage) createContainer() {
 	searchVbox := container.NewVBox(layout.NewSpacer(), g.searcher, layout.NewSpacer())
-	gr := g.grid
-	if searchGrid {
-		gr = g.searchGrid
-	}
 	playRandomVbox := container.NewVBox(layout.NewSpacer(), g.playRandom, layout.NewSpacer())
 	g.container = container.NewBorder(
 		container.NewHBox(util.NewHSpace(6),
 			g.titleDisp, playRandomVbox, layout.NewSpacer(), container.NewCenter(g.filterBtn), searchVbox, util.NewHSpace(15)),
-		nil, nil, nil, gr,
+		nil, nil, nil, g.grid,
 	)
 }
 
 func restoreGenrePage(saved *savedGenrePage) *GenrePage {
 	g := &GenrePage{
-		genre:      saved.genre,
-		contr:      saved.contr,
-		pm:         saved.pm,
-		mp:         saved.mp,
-		im:         saved.im,
-		searchText: saved.searchText,
-		filter:     saved.filter,
+		genre:           saved.genre,
+		pool:            saved.pool,
+		contr:           saved.contr,
+		pm:              saved.pm,
+		mp:              saved.mp,
+		im:              saved.im,
+		gridState:       saved.gridState,
+		searchGridState: saved.searchGridState,
+		searchText:      saved.searchText,
+		filter:          saved.filter,
 	}
 	g.ExtendBaseWidget(g)
 
@@ -102,12 +110,19 @@ func restoreGenrePage(saved *savedGenrePage) *GenrePage {
 		SizeName: theme.SizeNameHeadingText,
 	}
 	g.playRandom = widget.NewButtonWithIcon(" Play random", myTheme.ShuffleIcon, g.playRandomSongs)
-	g.grid = widgets.NewGridViewFromState(saved.gridState)
-	g.createSearchAndFilter()
+	state := saved.gridState
 	if g.searchText != "" {
-		g.searchGrid = widgets.NewGridViewFromState(saved.searchGridState)
+		state = saved.searchGridState
 	}
-	g.createContainer(saved.searchText != "")
+	if gv := g.pool.Obtain(util.WidgetTypeGridView); gv != nil {
+		g.grid = gv.(*widgets.GridView)
+		g.grid.Placeholder = myTheme.AlbumIcon
+		g.grid.ResetFromState(state)
+	} else {
+		g.grid = widgets.NewGridViewFromState(state)
+	}
+	g.createSearchAndFilter()
+	g.createContainer()
 
 	return g
 }
@@ -126,24 +141,29 @@ func (g *GenrePage) Reload() {
 	} else {
 		iter := g.mp.IterateAlbums("", g.filter)
 		g.grid.Reset(widgets.NewGridViewAlbumIterator(iter))
-		g.grid.Refresh()
 	}
 }
 
 func (g *GenrePage) Save() SavedPage {
 	sg := &savedGenrePage{
-		genre:      g.genre,
-		filter:     g.filter,
-		searchText: g.searchText,
-		contr:      g.contr,
-		pm:         g.pm,
-		mp:         g.mp,
-		im:         g.im,
-		gridState:  g.grid.SaveToState(),
+		genre:           g.genre,
+		pool:            g.pool,
+		filter:          g.filter,
+		searchText:      g.searchText,
+		contr:           g.contr,
+		pm:              g.pm,
+		mp:              g.mp,
+		im:              g.im,
+		gridState:       g.gridState,
+		searchGridState: g.searchGridState,
 	}
-	if g.searchGrid != nil {
-		sg.searchGridState = g.searchGrid.SaveToState()
+	if g.searchText != "" {
+		sg.searchGridState = g.grid.SaveToState()
+	} else {
+		sg.gridState = g.grid.SaveToState()
 	}
+	g.grid.Clear()
+	g.pool.Release(util.WidgetTypeGridView, g.grid)
 	return sg
 }
 
@@ -154,28 +174,20 @@ func (g *GenrePage) SearchWidget() fyne.Focusable {
 }
 
 func (g *GenrePage) OnSearched(query string) {
-	g.searchText = query
 	if query == "" {
-		g.container.Objects[0] = g.grid
-		if g.searchGrid != nil {
-			g.searchGrid.Clear()
-		}
-		g.Refresh()
-		return
+		g.grid.ResetFromState(g.gridState)
+	} else {
+		g.doSearch(query)
 	}
-	g.doSearch(query)
+	g.searchText = query
 }
 
 func (g *GenrePage) doSearch(query string) {
-	iter := g.mp.SearchAlbums(query, g.filter)
-	if g.searchGrid == nil {
-		g.searchGrid = widgets.NewGridView(widgets.NewGridViewAlbumIterator(iter), g.im, myTheme.AlbumIcon)
-		g.contr.ConnectAlbumGridActions(g.searchGrid)
-	} else {
-		g.searchGrid.Reset(widgets.NewGridViewAlbumIterator(iter))
+	if g.searchText == "" {
+		g.gridState = g.grid.SaveToState()
 	}
-	g.container.Objects[0] = g.searchGrid
-	g.Refresh()
+	iter := g.mp.SearchAlbums(query, g.filter)
+	g.grid.Reset(widgets.NewGridViewAlbumIterator(iter))
 }
 
 func (g *GenrePage) playRandomSongs() {
@@ -185,13 +197,14 @@ func (g *GenrePage) playRandomSongs() {
 type savedGenrePage struct {
 	genre           string
 	searchText      string
+	pool            *util.WidgetPool
 	filter          mediaprovider.AlbumFilter
 	contr           *controller.Controller
 	pm              *backend.PlaybackManager
 	mp              mediaprovider.MediaProvider
 	im              *backend.ImageManager
-	gridState       widgets.GridViewState
-	searchGridState widgets.GridViewState
+	gridState       *widgets.GridViewState
+	searchGridState *widgets.GridViewState
 }
 
 func (s *savedGenrePage) Restore() Page {

ui/browsing/nowplayingpage.go

@@ -38,6 +38,7 @@ type NowPlayingPage struct {
 
 type nowPlayingPageState struct {
 	contr *controller.Controller
+	pool  *util.WidgetPool
 	conf  *backend.NowPlayingPageConfig
 	pm    *backend.PlaybackManager
 	p     *player.Player
@@ -46,30 +47,40 @@ type nowPlayingPageState struct {
 func NewNowPlayingPage(
 	highlightedTrackID string,
 	contr *controller.Controller,
+	pool *util.WidgetPool,
 	conf *backend.NowPlayingPageConfig,
 	pm *backend.PlaybackManager,
 	p *player.Player, // TODO: once other player backends are supported (eg uPnP), refactor
 ) *NowPlayingPage {
-	a := &NowPlayingPage{nowPlayingPageState: nowPlayingPageState{contr: contr, conf: conf, pm: pm, p: p}}
+	a := &NowPlayingPage{nowPlayingPageState: nowPlayingPageState{
+		contr: contr, pool: pool, conf: conf, pm: pm, p: p,
+	}}
 	a.ExtendBaseWidget(a)
 
 	p.OnPaused(a.formatStatusLine)
 	p.OnPlaying(a.formatStatusLine)
 	p.OnStopped(a.formatStatusLine)
 
-	a.tracklist = widgets.NewTracklist(nil)
+	if t := a.pool.Obtain(util.WidgetTypeTracklist); t != nil {
+		a.tracklist = t.(*widgets.Tracklist)
+		a.tracklist.Reset()
+	} else {
+		a.tracklist = widgets.NewTracklist(nil)
+	}
 	a.tracklist.SetVisibleColumns(conf.TracklistColumns)
 	a.tracklist.OnVisibleColumnsChanged = func(cols []string) {
 		a.conf.TracklistColumns = cols
 	}
-	a.tracklist.AutoNumber = true
-	a.tracklist.DisablePlaybackMenu = true
+	a.tracklist.Options = widgets.TracklistOptions{
+		AutoNumber:          true,
+		DisablePlaybackMenu: true,
+		AuxiliaryMenuItems: []*fyne.MenuItem{
+			fyne.NewMenuItem("Remove from queue", a.onRemoveSelectedFromQueue),
+		},
+	}
 	contr.ConnectTracklistActions(a.tracklist)
 	// override the default OnPlayTrackAt handler b/c we don't need to re-load the tracks into the queue
 	a.tracklist.OnPlayTrackAt = a.onPlayTrackAt
-	a.tracklist.AuxiliaryMenuItems = []*fyne.MenuItem{
-		fyne.NewMenuItem("Remove from queue", a.onRemoveSelectedFromQueue),
-	}
 	a.title = widget.NewRichTextWithText("Now Playing")
 	a.title.Segments[0].(*widget.TextSegment).Style.SizeName = widget.RichTextStyleHeading.SizeName
 	a.statusLabel = widget.NewRichTextWithText("Stopped")
@@ -88,6 +99,8 @@ func (a *NowPlayingPage) CreateRenderer() fyne.WidgetRenderer {
 }
 
 func (a *NowPlayingPage) Save() SavedPage {
+	a.tracklist.Clear()
+	a.pool.Release(util.WidgetTypeTracklist, a.tracklist)
 	nps := a.nowPlayingPageState
 	return &nps
 }
@@ -205,5 +218,5 @@ func (a *NowPlayingPage) load(highlightedTrackID string) {
 }
 
 func (s *nowPlayingPageState) Restore() Page {
-	return NewNowPlayingPage("", s.contr, s.conf, s.pm, s.p)
+	return NewNowPlayingPage("", s.contr, s.pool, s.conf, s.pm, s.p)
 }

ui/browsing/playlistpage.go

@@ -24,6 +24,7 @@ type PlaylistPage struct {
 
 	playlistPageState
 
+	disposed     bool
 	header       *PlaylistPageHeader
 	tracklist    *widgets.Tracklist
 	tracks       []*mediaprovider.Track
@@ -35,6 +36,7 @@ type playlistPageState struct {
 	playlistID string
 	conf       *backend.PlaylistPageConfig
 	contr      *controller.Controller
+	widgetPool *util.WidgetPool
 	sm         *backend.ServerManager
 	pm         *backend.PlaybackManager
 	im         *backend.ImageManager
@@ -44,27 +46,41 @@ type playlistPageState struct {
 func NewPlaylistPage(
 	playlistID string,
 	conf *backend.PlaylistPageConfig,
+	pool *util.WidgetPool,
 	contr *controller.Controller,
 	sm *backend.ServerManager,
 	pm *backend.PlaybackManager,
 	im *backend.ImageManager,
 ) *PlaylistPage {
-	return newPlaylistPage(playlistID, conf, contr, sm, pm, im, widgets.TracklistSort{})
+	return newPlaylistPage(playlistID, conf, contr, pool, sm, pm, im, widgets.TracklistSort{})
 }
 
 func newPlaylistPage(
 	playlistID string,
 	conf *backend.PlaylistPageConfig,
 	contr *controller.Controller,
+	pool *util.WidgetPool,
 	sm *backend.ServerManager,
 	pm *backend.PlaybackManager,
 	im *backend.ImageManager,
 	trackSort widgets.TracklistSort,
 ) *PlaylistPage {
-	a := &PlaylistPage{playlistPageState: playlistPageState{playlistID: playlistID, conf: conf, contr: contr, sm: sm, pm: pm, im: im}}
+	a := &PlaylistPage{playlistPageState: playlistPageState{playlistID: playlistID, conf: conf, contr: contr, widgetPool: pool, sm: sm, pm: pm, im: im}}
 	a.ExtendBaseWidget(a)
-	a.header = NewPlaylistPageHeader(a)
-	a.tracklist = widgets.NewTracklist(nil)
+	if h := a.widgetPool.Obtain(util.WidgetTypePlaylistPageHeader); h != nil {
+		a.header = h.(*PlaylistPageHeader)
+		a.header.page = a
+		a.header.Clear()
+	} else {
+		a.header = NewPlaylistPageHeader(a)
+	}
+	a.header.page = a
+	if tl := a.widgetPool.Obtain(util.WidgetTypeTracklist); tl != nil {
+		a.tracklist = tl.(*widgets.Tracklist)
+		a.tracklist.Reset()
+	} else {
+		a.tracklist = widgets.NewTracklist(nil)
+	}
 	a.tracklist.SetVisibleColumns(conf.TracklistColumns)
 	a.tracklist.SetSorting(trackSort)
 	a.tracklist.OnVisibleColumnsChanged = func(cols []string) {
@@ -77,8 +93,10 @@ func newPlaylistPage(
 		fyne.NewMenuItem("Move down", a.onMoveSelectedDown),
 		fyne.NewMenuItem("Move to bottom", a.onMoveSelectedToBottom),
 	}...)
-	a.tracklist.AuxiliaryMenuItems = []*fyne.MenuItem{reorderMenu,
-		fyne.NewMenuItem("Remove from playlist", a.onRemoveSelectedFromPlaylist)}
+	a.tracklist.Options = widgets.TracklistOptions{
+		AuxiliaryMenuItems: []*fyne.MenuItem{reorderMenu,
+			fyne.NewMenuItem("Remove from playlist", a.onRemoveSelectedFromPlaylist)},
+	}
 	// connect tracklist actions
 	a.contr.ConnectTracklistActions(a.tracklist)
 
@@ -94,8 +112,12 @@ func (a *PlaylistPage) CreateRenderer() fyne.WidgetRenderer {
 }
 
 func (a *PlaylistPage) Save() SavedPage {
+	a.disposed = true
 	p := a.playlistPageState
 	p.trackSort = a.tracklist.Sorting()
+	p.widgetPool.Release(util.WidgetTypePlaylistPageHeader, a.header)
+	a.tracklist.Clear()
+	p.widgetPool.Release(util.WidgetTypeTracklist, a.tracklist)
 	return &p
 }
 
@@ -132,6 +154,9 @@ func (a *PlaylistPage) load() {
 		log.Printf("Failed to get playlist: %s", err.Error())
 		return
 	}
+	if a.disposed {
+		return
+	}
 	renumberTracks(playlist.Tracks)
 	a.tracks = playlist.Tracks
 	a.tracklist.SetTracks(playlist.Tracks)
@@ -200,7 +225,7 @@ func (a *PlaylistPage) onRemoveSelectedFromPlaylist() {
 	}
 	a.sm.Server.EditPlaylistTracks(a.playlistID, nil, idxs)
 	a.tracklist.UnselectAll()
-	go a.Reload()
+	a.Reload()
 }
 
 type PlaylistPageHeader struct {
@@ -280,6 +305,14 @@ func NewPlaylistPageHeader(page *PlaylistPage) *PlaylistPageHeader {
 	return a
 }
 
+func (a *PlaylistPageHeader) Clear() {
+	a.titleLabel.Segments[0].(*widget.TextSegment).Text = ""
+	a.createdAtLabel.Text = ""
+	a.descriptionLabel.Text = ""
+	a.ownerLabel.Text = ""
+	a.image.SetImage(nil, false)
+}
+
 func (a *PlaylistPageHeader) CreateRenderer() fyne.WidgetRenderer {
 	return widget.NewSimpleRenderer(a.container)
 }
@@ -325,5 +358,5 @@ func (a *PlaylistPageHeader) formatPlaylistTrackTimeStr(p *mediaprovider.Playlis
 }
 
 func (s *playlistPageState) Restore() Page {
-	return newPlaylistPage(s.playlistID, s.conf, s.contr, 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)
 }

ui/browsing/playlistspage.go

@@ -13,6 +13,7 @@ import (
 	"github.com/dweymouth/supersonic/ui/controller"
 	"github.com/dweymouth/supersonic/ui/layouts"
 	myTheme "github.com/dweymouth/supersonic/ui/theme"
+	"github.com/dweymouth/supersonic/ui/util"
 	"github.com/dweymouth/supersonic/ui/widgets"
 
 	"fyne.io/fyne/v2"
@@ -25,6 +26,7 @@ import (
 type PlaylistsPage struct {
 	widget.BaseWidget
 
+	pool              *util.WidgetPool
 	cfg               *backend.PlaylistsPageConfig
 	contr             *controller.Controller
 	mp                mediaprovider.MediaProvider
@@ -39,16 +41,17 @@ type PlaylistsPage struct {
 	gridView   *widgets.GridView
 }
 
-func NewPlaylistsPage(contr *controller.Controller, cfg *backend.PlaylistsPageConfig, mp mediaprovider.MediaProvider) *PlaylistsPage {
+func NewPlaylistsPage(contr *controller.Controller, pool *util.WidgetPool, cfg *backend.PlaylistsPageConfig, mp mediaprovider.MediaProvider) *PlaylistsPage {
 	activeView := 0
 	if cfg.InitialView == "Grid" {
 		activeView = 1
 	}
-	return newPlaylistsPage(contr, cfg, mp, "", activeView)
+	return newPlaylistsPage(contr, pool, cfg, mp, "", activeView)
 }
 
-func newPlaylistsPage(contr *controller.Controller, cfg *backend.PlaylistsPageConfig, mp mediaprovider.MediaProvider, searchText string, activeView int) *PlaylistsPage {
+func newPlaylistsPage(contr *controller.Controller, pool *util.WidgetPool, cfg *backend.PlaylistsPageConfig, mp mediaprovider.MediaProvider, searchText string, activeView int) *PlaylistsPage {
 	a := &PlaylistsPage{
+		pool:      pool,
 		cfg:       cfg,
 		mp:        mp,
 		contr:     contr,
@@ -95,7 +98,13 @@ func (a *PlaylistsPage) createListView() {
 
 func (a *PlaylistsPage) createGridView(playlists []*mediaprovider.Playlist) {
 	model := createPlaylistGridViewModel(playlists)
-	a.gridView = widgets.NewFixedGridView(model, a.contr.App.ImageManager, myTheme.PlaylistIcon)
+	if g := a.pool.Obtain(util.WidgetTypeGridView); g != nil {
+		a.gridView = g.(*widgets.GridView)
+		a.gridView.Placeholder = myTheme.PlaylistIcon
+		a.gridView.ResetFixed(model)
+	} else {
+		a.gridView = widgets.NewFixedGridView(model, a.contr.App.ImageManager, myTheme.PlaylistIcon)
+	}
 	a.gridView.OnPlay = func(id string, shuffle bool) {
 		go a.contr.App.PlaybackManager.PlayPlaylist(id, 0, shuffle)
 	}
@@ -103,6 +112,7 @@ func (a *PlaylistsPage) createGridView(playlists []*mediaprovider.Playlist) {
 		go a.contr.App.PlaybackManager.LoadPlaylist(id, true, false)
 	}
 	a.gridView.OnShowItemPage = a.showPlaylistPage
+	a.gridView.OnShowSecondaryPage = nil
 	a.gridView.OnAddToPlaylist = func(id string) {
 		go func() {
 			pl, err := a.contr.App.ServerManager.Server.GetPlaylist(id)
@@ -221,17 +231,24 @@ func (a *PlaylistsPage) Reload() {
 }
 
 func (a *PlaylistsPage) Save() SavedPage {
-	return &savedPlaylistsPage{
+	s := &savedPlaylistsPage{
 		contr:      a.contr,
+		pool:       a.pool,
 		cfg:        a.cfg,
 		mp:         a.mp,
 		searchText: a.searcher.Entry.Text,
 		activeView: a.viewToggle.ActivatedButtonIndex(),
 	}
+	if a.gridView != nil {
+		a.gridView.Clear()
+		a.pool.Release(util.WidgetTypeGridView, a.gridView)
+	}
+	return s
 }
 
 type savedPlaylistsPage struct {
 	contr      *controller.Controller
+	pool       *util.WidgetPool
 	cfg        *backend.PlaylistsPageConfig
 	mp         mediaprovider.MediaProvider
 	searchText string
@@ -239,7 +256,7 @@ type savedPlaylistsPage struct {
 }
 
 func (s *savedPlaylistsPage) Restore() Page {
-	return newPlaylistsPage(s.contr, s.cfg, s.mp, s.searchText, s.activeView)
+	return newPlaylistsPage(s.contr, s.pool, s.cfg, s.mp, s.searchText, s.activeView)
 }
 
 func (a *PlaylistsPage) buildContainer(initialView fyne.CanvasObject) {

ui/browsing/router.go

@@ -3,6 +3,7 @@ package browsing
 import (
 	"github.com/dweymouth/supersonic/backend"
 	"github.com/dweymouth/supersonic/ui/controller"
+	"github.com/dweymouth/supersonic/ui/util"
 )
 
 type NavigationHandler interface {
@@ -14,6 +15,7 @@ type Router struct {
 	App        *backend.App
 	Controller *controller.Controller
 	Nav        NavigationHandler
+	widgetPool *util.WidgetPool
 }
 
 func NewRouter(app *backend.App, controller *controller.Controller, nav NavigationHandler) Router {
@@ -21,6 +23,7 @@ func NewRouter(app *backend.App, controller *controller.Controller, nav Navigati
 		App:        app,
 		Controller: controller,
 		Nav:        nav,
+		widgetPool: util.NewWidgetPool(),
 	}
 	return r
 }
@@ -28,27 +31,27 @@ func NewRouter(app *backend.App, controller *controller.Controller, nav Navigati
 func (r Router) CreatePage(rte controller.Route) Page {
 	switch rte.Page {
 	case controller.Album:
-		return NewAlbumPage(rte.Arg, &r.App.Config.AlbumPage, r.App.PlaybackManager, r.App.ServerManager.Server, r.App.ImageManager, r.Controller)
+		return NewAlbumPage(rte.Arg, &r.App.Config.AlbumPage, r.widgetPool, r.App.PlaybackManager, r.App.ServerManager.Server, r.App.ImageManager, r.Controller)
 	case controller.Albums:
-		return NewAlbumsPage(&r.App.Config.AlbumsPage, r.Controller, r.App.PlaybackManager, r.App.ServerManager.Server, r.App.ImageManager)
+		return NewAlbumsPage(&r.App.Config.AlbumsPage, r.widgetPool, r.Controller, r.App.PlaybackManager, r.App.ServerManager.Server, r.App.ImageManager)
 	case controller.Artist:
-		return NewArtistPage(rte.Arg, &r.App.Config.ArtistPage, r.App.PlaybackManager, r.App.ServerManager.Server, r.App.ImageManager, r.Controller)
+		return NewArtistPage(rte.Arg, &r.App.Config.ArtistPage, r.widgetPool, r.App.PlaybackManager, r.App.ServerManager.Server, r.App.ImageManager, r.Controller)
 	case controller.Artists:
-		return NewArtistsPage(r.Controller, r.App.PlaybackManager, r.App.ServerManager.Server, r.App.ImageManager)
+		return NewArtistsPage(r.Controller, r.widgetPool, r.App.PlaybackManager, r.App.ServerManager.Server, r.App.ImageManager)
 	case controller.Favorites:
-		return NewFavoritesPage(&r.App.Config.FavoritesPage, r.Controller, r.App.ServerManager.Server, r.App.PlaybackManager, r.App.ImageManager)
+		return NewFavoritesPage(&r.App.Config.FavoritesPage, r.widgetPool, r.Controller, r.App.ServerManager.Server, r.App.PlaybackManager, r.App.ImageManager)
 	case controller.Genre:
-		return NewGenrePage(rte.Arg, r.Controller, r.App.PlaybackManager, r.App.ServerManager.Server, r.App.ImageManager)
+		return NewGenrePage(rte.Arg, r.widgetPool, r.Controller, r.App.PlaybackManager, r.App.ServerManager.Server, r.App.ImageManager)
 	case controller.Genres:
 		return NewGenresPage(r.Controller, r.App.ServerManager.Server)
 	case controller.NowPlaying:
-		return NewNowPlayingPage(rte.Arg, r.Controller, &r.App.Config.NowPlayingPage, r.App.PlaybackManager, r.App.Player)
+		return NewNowPlayingPage(rte.Arg, r.Controller, r.widgetPool, &r.App.Config.NowPlayingPage, r.App.PlaybackManager, r.App.Player)
 	case controller.Playlist:
-		return NewPlaylistPage(rte.Arg, &r.App.Config.PlaylistPage, r.Controller, r.App.ServerManager, r.App.PlaybackManager, r.App.ImageManager)
+		return NewPlaylistPage(rte.Arg, &r.App.Config.PlaylistPage, r.widgetPool, r.Controller, r.App.ServerManager, r.App.PlaybackManager, r.App.ImageManager)
 	case controller.Playlists:
-		return NewPlaylistsPage(r.Controller, &r.App.Config.PlaylistsPage, r.App.ServerManager.Server)
+		return NewPlaylistsPage(r.Controller, r.widgetPool, &r.App.Config.PlaylistsPage, r.App.ServerManager.Server)
 	case controller.Tracks:
-		return NewTracksPage(r.Controller, &r.App.Config.TracksPage, r.App.ServerManager.Server)
+		return NewTracksPage(r.Controller, &r.App.Config.TracksPage, r.widgetPool, r.App.ServerManager.Server)
 	}
 	return nil
 }

ui/browsing/trackspage.go

@@ -7,6 +7,7 @@ import (
 	"github.com/dweymouth/supersonic/ui/controller"
 	"github.com/dweymouth/supersonic/ui/layouts"
 	"github.com/dweymouth/supersonic/ui/theme"
+	"github.com/dweymouth/supersonic/ui/util"
 	"github.com/dweymouth/supersonic/ui/widgets"
 
 	"fyne.io/fyne/v2"
@@ -34,18 +35,26 @@ type TracksPage struct {
 
 type tracksPageState struct {
 	searchText string
+	widgetPool *util.WidgetPool
 	contr      *controller.Controller
 	conf       *backend.TracksPageConfig
 	mp         mediaprovider.MediaProvider
 }
 
-func NewTracksPage(contr *controller.Controller, conf *backend.TracksPageConfig, mp mediaprovider.MediaProvider) *TracksPage {
-	t := &TracksPage{tracksPageState: tracksPageState{contr: contr, conf: conf, mp: mp}}
+func NewTracksPage(contr *controller.Controller, conf *backend.TracksPageConfig, pool *util.WidgetPool, mp mediaprovider.MediaProvider) *TracksPage {
+	t := &TracksPage{tracksPageState: tracksPageState{contr: contr, conf: conf, widgetPool: pool, mp: mp}}
 	t.ExtendBaseWidget(t)
 
-	t.tracklist = widgets.NewTracklist(nil)
-	t.tracklist.DisableSorting = true
-	t.tracklist.AutoNumber = true
+	if tl := t.widgetPool.Obtain(util.WidgetTypeTracklist); tl != nil {
+		t.tracklist = tl.(*widgets.Tracklist)
+		t.tracklist.Reset()
+	} else {
+		t.tracklist = widgets.NewTracklist(nil)
+	}
+	t.tracklist.Options = widgets.TracklistOptions{
+		DisableSorting: true,
+		AutoNumber:     true,
+	}
 	t.tracklist.SetVisibleColumns(conf.TracklistColumns)
 	t.tracklist.OnVisibleColumnsChanged = func(cols []string) {
 		t.conf.TracklistColumns = cols
@@ -119,7 +128,7 @@ func (t *TracksPage) OnSearched(query string) {
 func (t *TracksPage) doSearch(query string) {
 	if t.searchTracklist == nil {
 		t.searchTracklist = widgets.NewTracklist(nil)
-		t.searchTracklist.AutoNumber = true
+		t.searchTracklist.Options = widgets.TracklistOptions{AutoNumber: true}
 		t.searchTracklist.SetVisibleColumns(t.conf.TracklistColumns)
 		t.searchTracklist.SetNowPlaying(t.nowPlayingID)
 		t.searchTracklist.OnVisibleColumnsChanged = func(cols []string) {
@@ -141,12 +150,15 @@ func (t *TracksPage) CreateRenderer() fyne.WidgetRenderer {
 }
 
 func (t *TracksPage) Save() SavedPage {
+	t.loader.Dispose()
+	t.tracklist.Clear()
+	t.widgetPool.Release(util.WidgetTypeTracklist, t.tracklist)
 	state := t.tracksPageState
 	return &state
 }
 
 func (s *tracksPageState) Restore() Page {
-	t := NewTracksPage(s.contr, s.conf, s.mp)
+	t := NewTracksPage(s.contr, s.conf, s.widgetPool, s.mp)
 	t.searchText = s.searchText
 	if t.searchText != "" {
 		t.searcher.Entry.Text = t.searchText

ui/util/widgetpool.go

@@ -0,0 +1,99 @@
+package util
+
+import (
+	"sync"
+	"time"
+
+	"fyne.io/fyne/v2"
+)
+
+type WidgetType int
+
+const (
+	WidgetTypeAlbumPageHeader WidgetType = iota
+	WidgetTypeArtistPageHeader
+	WidgetTypeGridView
+	WidgetTypePlaylistPageHeader
+	WidgetTypeTracklist
+
+	// keep at bottom
+	numWidgetTypes
+)
+
+const (
+	multipleItemsExpiry = 2 * time.Minute
+	singleItemExpiry    = 5 * time.Minute
+)
+
+// A pool to share commonly-used widgets across pages to reduce
+// creation of new widgets and memory allocations.
+type WidgetPool struct {
+	mut   sync.Mutex
+	pools [][]pooledWidget
+}
+
+type pooledWidget struct {
+	widget     fyne.CanvasObject
+	releasedAt int64 // unixMillis
+}
+
+func NewWidgetPool() *WidgetPool {
+	p := &WidgetPool{
+		pools: make([][]pooledWidget, numWidgetTypes),
+	}
+	go func() {
+		t := time.NewTicker(2 * time.Minute)
+		for range t.C {
+			p.cleanUpExpiredItems()
+		}
+	}()
+	return p
+}
+
+// Obtain obtains a widget of the given type from the pool, if one exists.
+// Returns nil if there is no available widget.
+func (w *WidgetPool) Obtain(typ WidgetType) fyne.CanvasObject {
+	w.mut.Lock()
+	defer w.mut.Unlock()
+	var widget fyne.CanvasObject
+	if l := len(w.pools[typ]); l > 0 {
+		i := l - 1
+		widget = w.pools[typ][i].widget
+		w.pools[typ][i].widget = nil
+		w.pools[typ] = w.pools[typ][:i]
+	}
+	return widget
+}
+
+// Release releases a widget into the pool.
+// The widget must not be modified by the releaser after release,
+// since it may be Obtained for a new use at any time.
+func (w *WidgetPool) Release(typ WidgetType, wid fyne.CanvasObject) {
+	w.mut.Lock()
+	defer w.mut.Unlock()
+	w.pools[typ] = append(w.pools[typ], pooledWidget{
+		widget:     wid,
+		releasedAt: time.Now().UnixMilli(),
+	})
+}
+
+func (w *WidgetPool) cleanUpExpiredItems() {
+	w.mut.Lock()
+	defer w.mut.Unlock()
+	for widTyp, pool := range w.pools {
+		newP := make([]pooledWidget, 0, len(pool))
+		l := len(pool)
+		for _, wid := range pool {
+			timeSinceRelease := time.Since(time.UnixMilli(wid.releasedAt))
+			if l > 1 && timeSinceRelease > multipleItemsExpiry {
+				l-- // let expire if >1 item in pool and released long enough ago
+			} else if l == 1 && timeSinceRelease > singleItemExpiry {
+				l-- // let expire if last item in pool and released long enough ago
+			} else {
+				newP = append(newP, wid) // not expired
+			}
+		}
+		// re-assign non-expired items back to this widget type pool
+		w.pools[widTyp] = newP
+	}
+}

ui/util/widgetpool_test.go

@@ -0,0 +1,24 @@
+package util
+
+import (
+	"testing"
+	"time"
+)
+
+func Test_WidgetPool_CleanupExpiredItems(t *testing.T) {
+	now := time.Now()
+	threeMinAgo := now.Add(-3 * time.Minute)
+	w := &WidgetPool{
+		pools: [][]pooledWidget{
+			{
+				{releasedAt: threeMinAgo.UnixMilli()},
+				{releasedAt: threeMinAgo.UnixMilli()},
+				{releasedAt: threeMinAgo.UnixMilli()},
+			},
+		},
+	}
+	w.cleanUpExpiredItems()
+	if l := len(w.pools[0]); l != 1 {
+		t.Errorf("Expected one widget in pool after cleanup, got %d", l)
+	}
+}

ui/widgets/gridview.go

@@ -71,6 +71,8 @@ func NewGridViewAlbumIterator(iter mediaprovider.AlbumIterator) GridViewIterator
 type GridView struct {
 	widget.BaseWidget
 
+	stateMutex  sync.RWMutex
+	fetchCancel context.CancelFunc
 	GridViewState
 
 	grid *xwidget.GridWrap
@@ -78,12 +80,10 @@ type GridView struct {
 
 type GridViewState struct {
 	items        []GridViewItemModel
-	itemsMutex   sync.RWMutex
 	iter         GridViewIterator
 	imageFetcher ImageFetcher
-	placeholder  fyne.Resource
+	Placeholder  fyne.Resource
 	highestShown int
-	fetchCancel  context.CancelFunc
 	done         bool
 
 	OnPlay              func(id string, shuffle bool)
@@ -104,7 +104,7 @@ func NewFixedGridView(items []GridViewItemModel, fetch ImageFetcher, placeholder
 			items:        items,
 			done:         true,
 			imageFetcher: fetch,
-			placeholder:  placeholder,
+			Placeholder:  placeholder,
 		},
 	}
 	g.ExtendBaseWidget(g)
@@ -117,7 +117,7 @@ func NewGridView(iter GridViewIterator, fetch ImageFetcher, placeholder fyne.Res
 		GridViewState: GridViewState{
 			iter:         iter,
 			imageFetcher: fetch,
-			placeholder:  placeholder,
+			Placeholder:  placeholder,
 		},
 	}
 	g.ExtendBaseWidget(g)
@@ -128,14 +128,16 @@ func NewGridView(iter GridViewIterator, fetch ImageFetcher, placeholder fyne.Res
 	return g
 }
 
-func (g *GridView) SaveToState() GridViewState {
+func (g *GridView) SaveToState() *GridViewState {
+	g.stateMutex.RLock()
 	s := g.GridViewState
+	g.stateMutex.RUnlock()
 	s.scrollPos = g.grid.GetScrollOffset()
-	return s
+	return &s
 }
 
-func NewGridViewFromState(state GridViewState) *GridView {
-	g := &GridView{GridViewState: state}
+func NewGridViewFromState(state *GridViewState) *GridView {
+	g := &GridView{GridViewState: *state}
 	g.ExtendBaseWidget(g)
 	g.createGridWrap()
 	g.Refresh() // needed to initialize the widget
@@ -144,8 +146,12 @@ func NewGridViewFromState(state GridViewState) *GridView {
 }
 
 func (g *GridView) Clear() {
-	g.itemsMutex.Lock()
-	defer g.itemsMutex.Unlock()
+	if g.fetchCancel != nil {
+		g.fetchCancel()
+		g.fetchCancel = nil
+	}
+	g.stateMutex.Lock()
+	defer g.stateMutex.Unlock()
 	g.items = nil
 	g.done = true
 }
@@ -155,13 +161,27 @@ func (g *GridView) Reset(iter GridViewIterator) {
 		g.fetchCancel()
 		g.fetchCancel = nil
 	}
-	g.itemsMutex.Lock()
+	g.stateMutex.Lock()
 	g.items = nil
 	g.done = false
 	g.highestShown = 0
 	g.iter = iter
-	g.itemsMutex.Unlock()
+	g.stateMutex.Unlock()
 	g.fetchMoreItems(36)
+	g.Refresh()
+}
+
+func (g *GridView) ResetFromState(state *GridViewState) {
+	if g.fetchCancel != nil {
+		g.fetchCancel()
+		g.fetchCancel = nil
+	}
+	g.stateMutex.Lock()
+	g.GridViewState = *state
+	g.stateMutex.Unlock()
+	g.grid.Refresh()
+	g.grid.ScrollToOffset(state.scrollPos)
+	g.grid.Refresh()
 }
 
 func (g *GridView) ResetFixed(items []GridViewItemModel) {
@@ -169,12 +189,13 @@ func (g *GridView) ResetFixed(items []GridViewItemModel) {
 		g.fetchCancel()
 		g.fetchCancel = nil
 	}
-	g.itemsMutex.Lock()
+	g.stateMutex.Lock()
 	g.items = items
-	g.itemsMutex.Unlock()
 	g.done = true
 	g.highestShown = 0
 	g.iter = nil
+	g.stateMutex.Unlock()
+	g.Refresh()
 }
 
 func (g *GridView) GetScrollOffset() float32 {
@@ -192,7 +213,7 @@ func (g *GridView) createGridWrap() {
 		},
 		// create func
 		func() fyne.CanvasObject {
-			card := NewGridViewItem(g.placeholder)
+			card := NewGridViewItem(g.Placeholder)
 			card.OnPlay = func(shuffle bool) {
 				if g.OnPlay != nil {
 					g.OnPlay(card.ItemID(), shuffle)
@@ -220,7 +241,7 @@ func (g *GridView) createGridWrap() {
 			}
 			card.OnDownload = func() {
 				if g.OnDownload != nil {
-					g.OnDownload(card.itemID)
+					g.OnDownload(card.ItemID())
 				}
 			}
 			return card
@@ -238,13 +259,14 @@ func (g *GridView) doUpdateItemCard(itemIdx int, card *GridViewItem) {
 		g.highestShown = itemIdx
 	}
 	var item GridViewItemModel
-	g.itemsMutex.RLock()
+	g.stateMutex.RLock()
 	// itemIdx can rarely be out of range if the data is being updated
 	// as the view is requested to refresh
 	if itemIdx < len(g.items) {
 		item = g.items[itemIdx]
 	}
-	g.itemsMutex.RUnlock()
+	g.stateMutex.RUnlock()
+	card.Cover.Im.CenterIcon = g.Placeholder
 	if card.PrevID == item.ID {
 		// nothing to do
 		return
@@ -290,8 +312,8 @@ func (g *GridView) doUpdateItemCard(itemIdx int, card *GridViewItem) {
 }
 
 func (g *GridView) lenItems() int {
-	g.itemsMutex.RLock()
-	defer g.itemsMutex.RUnlock()
+	g.stateMutex.RLock()
+	defer g.stateMutex.RUnlock()
 	return len(g.items)
 }
 
@@ -314,15 +336,15 @@ func (g *GridView) fetchMoreItems(count int) {
 				case <-ctx.Done():
 					return
 				default:
-					g.itemsMutex.Lock()
+					g.stateMutex.Lock()
 					g.items = append(g.items, items...)
-					g.itemsMutex.Unlock()
+					g.stateMutex.Unlock()
 					if len(items) < batchFetchSize {
 						g.done = true
 					}
 					n += len(items)
 					if len(items) > 0 {
-						g.Refresh()
+						g.grid.Refresh()
 					}
 				}
 			}

ui/widgets/gridviewitem.go

@@ -211,6 +211,10 @@ func (g *GridViewItem) Update(model GridViewItemModel) {
 	g.Cover.ResetPlayButton()
 }
 
+func (g *GridViewItem) Refresh() {
+	g.BaseWidget.Refresh()
+}
+
 func (g *GridViewItem) ItemID() string {
 	return g.itemID
 }

ui/widgets/imageplaceholder.go

@@ -15,7 +15,8 @@ import (
 // a placeholder with a rectangular border frame
 // and an icon positioned in the center of the frame.
 type ImagePlaceholder struct {
-	ScaleMode canvas.ImageScale
+	ScaleMode  canvas.ImageScale
+	CenterIcon fyne.Resource
 
 	widget.BaseWidget
 	content   *fyne.Container
@@ -30,7 +31,7 @@ type ImagePlaceholder struct {
 }
 
 func NewImagePlaceholder(centerIcon fyne.Resource, minSize float32) *ImagePlaceholder {
-	i := &ImagePlaceholder{minSize: minSize}
+	i := &ImagePlaceholder{minSize: minSize, CenterIcon: centerIcon}
 	i.ExtendBaseWidget(i)
 	i.iconImage = canvas.NewImageFromResource(centerIcon)
 	i.iconImage.FillMode = canvas.ImageFillContain
@@ -86,6 +87,7 @@ func (i *ImagePlaceholder) MinSize() fyne.Size {
 
 func (i *ImagePlaceholder) Refresh() {
 	i.border.Hidden = i.HaveImage()
+	i.iconImage.Resource = i.CenterIcon
 	i.iconImage.Hidden = i.HaveImage()
 	i.imageDisp.Hidden = !i.HaveImage()
 	i.imageDisp.ScaleMode = i.ScaleMode

ui/widgets/tracklist.go

@@ -47,9 +47,7 @@ type TracklistSort struct {
 	ColumnName string
 }
 
-type Tracklist struct {
-	widget.BaseWidget
-
+type TracklistOptions struct {
 	// AutoNumber sets whether to auto-number the tracks 1..N in display order,
 	// or to use the number from the track's metadata
 	AutoNumber bool
@@ -68,6 +66,12 @@ type Tracklist struct {
 
 	// Disables sorting the tracklist by clicking individual columns.
 	DisableSorting bool
+}
+
+type Tracklist struct {
+	widget.BaseWidget
+
+	Options TracklistOptions
 
 	// user action callbacks
 	OnPlayTrackAt   func(int)
@@ -141,7 +145,7 @@ func NewTracklist(tracks []*mediaprovider.Track) *Tracklist {
 			tr := item.(*TrackRow)
 			tr.trackIdx = itemID
 			i := -1 // signal that we want to display the actual track num.
-			if t.AutoNumber {
+			if t.Options.AutoNumber {
 				i = itemID + 1
 			}
 			tr.Update(t.trackModelAt(itemID), i)
@@ -153,6 +157,13 @@ func NewTracklist(tracks []*mediaprovider.Track) *Tracklist {
 	return t
 }
 
+func (t *Tracklist) Reset() {
+	t.Clear()
+	t.Options = TracklistOptions{}
+	t.ctxMenu = nil
+	t.SetSorting(TracklistSort{})
+}
+
 func (t *Tracklist) buildHeader() {
 	t.hdr = NewListHeader([]ListColumn{
 		{Text: "#", Alignment: fyne.TextAlignTrailing, CanToggleVisible: false},
@@ -331,7 +342,7 @@ func (t *Tracklist) CreateRenderer() fyne.WidgetRenderer {
 }
 
 func (t *Tracklist) Refresh() {
-	t.hdr.DisableSorting = t.DisableSorting
+	t.hdr.DisableSorting = t.Options.DisableSorting
 	t.BaseWidget.Refresh()
 }
 
@@ -487,7 +498,7 @@ func (t *Tracklist) onShowContextMenu(e *fyne.PointEvent, trackIdx int) {
 	t.list.Refresh()
 	if t.ctxMenu == nil {
 		t.ctxMenu = fyne.NewMenu("")
-		if !t.DisablePlaybackMenu {
+		if !t.Options.DisablePlaybackMenu {
 			t.ctxMenu.Items = append(t.ctxMenu.Items,
 				fyne.NewMenuItem("Play", func() {
 					if t.OnPlaySelection != nil {
@@ -530,9 +541,9 @@ func (t *Tracklist) onShowContextMenu(e *fyne.PointEvent, trackIdx int) {
 			t.onSetRatings(t.selectedTracks(), rating, true)
 		})
 		t.ctxMenu.Items = append(t.ctxMenu.Items, ratingMenu)
-		if len(t.AuxiliaryMenuItems) > 0 {
+		if len(t.Options.AuxiliaryMenuItems) > 0 {
 			t.ctxMenu.Items = append(t.ctxMenu.Items, fyne.NewMenuItemSeparator())
-			t.ctxMenu.Items = append(t.ctxMenu.Items, t.AuxiliaryMenuItems...)
+			t.ctxMenu.Items = append(t.ctxMenu.Items, t.Options.AuxiliaryMenuItems...)
 		}
 	}
 	widget.ShowPopUpMenuAtPosition(t.ctxMenu, fyne.CurrentApp().Driver().CanvasForObject(t), e.AbsolutePosition)
@@ -754,7 +765,7 @@ func (t *TrackRow) Update(tm *trackModel, rowNum int) {
 		var str string
 		if rowNum < 0 {
 			rowNum = tr.TrackNumber
-			if t.tracklist.ShowDiscNumber {
+			if t.tracklist.Options.ShowDiscNumber {
 				discNum = tr.DiscNumber
 			}
 		}

ui/widgets/tracklistloader.go

@@ -7,6 +7,8 @@ import (
 // Component that manages lazily loading more tracks into a Tracklist
 // as the user scrolls near the bottom.
 type TracklistLoader struct {
+	disposed bool
+
 	tracklist *Tracklist
 	iter      mediaprovider.TrackIterator
 
@@ -28,11 +30,17 @@ func NewTracklistLoader(tracklist *Tracklist, iter mediaprovider.TrackIterator)
 	return t
 }
 
+// Cancels all asynchronous loads so that they will no longer modify the tracklist.
+func (t *TracklistLoader) Dispose() {
+	t.disposed = true
+	t.tracklist.OnTrackShown = nil
+}
+
 func (t *TracklistLoader) onTrackShown(tracknum int) {
 	if tracknum > t.highestShown {
 		t.highestShown = tracknum
 	}
-	if t.highestShown >= t.len-25 && !t.fetching && !t.done {
+	if t.highestShown >= t.len-25 && !t.fetching && !t.done && !t.disposed {
 		t.fetching = true
 		go t.loadMoreTracks(25)
 	}
@@ -52,6 +60,12 @@ func (t *TracklistLoader) loadMoreTracks(num int) {
 				break
 			}
 			t.trackBuffer = append(t.trackBuffer, tr)
+			if t.disposed {
+				break
+			}
+		}
+		if t.disposed {
+			return
 		}
 		t.tracklist.AppendTracks(t.trackBuffer)
 		t.tracklist.Refresh()