save only page state in history and reconstruct page UI

go.mod

@@ -44,4 +44,4 @@ require (
 	honnef.co/go/js/dom v0.0.0-20210725211120-f030747120f2 // indirect
 )
 
-replace fyne.io/fyne/v2 v2.2.4 => github.com/dweymouth/fyne/v2 v2.2.5-0.20221227225053-ae75dfbeb567
+replace fyne.io/fyne/v2 v2.2.4 => github.com/dweymouth/fyne/v2 v2.2.5-0.20230110012952-10b53c64afce

go.sum

@@ -72,8 +72,8 @@ github.com/danieljoos/wincred v1.1.0/go.mod h1:XYlo+eRTsVA9aHGp7NGjFkPla4m+DCL7h
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/dweymouth/fyne/v2 v2.2.5-0.20221227225053-ae75dfbeb567 h1:JEBJ5YN74ryKQNW1TgH0GjHkVpgmHMb1oYuz8ZShjY8=
+github.com/dweymouth/fyne/v2 v2.2.5-0.20230110012952-10b53c64afce h1:hoKExh5/o+OEO0Aq2IE3pwL8qSfRk/6JE/Y+82BKvuE=
-github.com/dweymouth/fyne/v2 v2.2.5-0.20221227225053-ae75dfbeb567/go.mod h1:MBoGuHzLLSXdQOWFAwWhIhYTEMp33zqtGCReSWhaQTA=
+github.com/dweymouth/fyne/v2 v2.2.5-0.20230110012952-10b53c64afce/go.mod h1:MBoGuHzLLSXdQOWFAwWhIhYTEMp33zqtGCReSWhaQTA=
 github.com/dweymouth/go-subsonic v0.0.0-20221214005741-bd8048fa1863 h1:bOWMpFJ9zY839T1EngQ5nxVCiMlatPtpGkg/yHK6szg=
 github.com/dweymouth/go-subsonic v0.0.0-20221214005741-bd8048fa1863/go.mod h1:fUez6NFiEJiQTZizZ1BThZr5GJXAbigzGYjEPNm4tdI=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=

ui/browsing/albumpage.go

@@ -52,6 +52,15 @@ func (a *AlbumPage) SetPlayAlbumCallback(cb func(string, int)) {
 	a.OnPlayAlbum = cb
 }
 
+func (a *AlbumPage) Save() SavedPage {
+	return &savedAlbumPage{
+		albumID: a.albumID,
+		lm:      a.lm,
+		im:      a.im,
+		nav:     a.nav,
+	}
+}
+
 func (a *AlbumPage) Route() Route {
 	return AlbumRoute(a.albumID)
 }
@@ -175,3 +184,14 @@ func (a *AlbumPageHeader) Update(album *subsonic.AlbumID3, im *backend.ImageMana
 func formatMiscLabelStr(a *subsonic.AlbumID3) string {
 	return fmt.Sprintf("%d · %d tracks · %s", a.Year, a.SongCount, util.SecondsToTimeString(float64(a.Duration)))
 }
+
+type savedAlbumPage struct {
+	albumID string
+	lm      *backend.LibraryManager
+	im      *backend.ImageManager
+	nav     func(Route)
+}
+
+func (s *savedAlbumPage) Restore() Page {
+	return NewAlbumPage(s.albumID, s.lm, s.im, s.nav)
+}

ui/browsing/albumspage.go

@@ -16,6 +16,7 @@ var _ fyne.Widget = (*AlbumsPage)(nil)
 type AlbumsPage struct {
 	widget.BaseWidget
 
+	title       string
 	im          *backend.ImageManager
 	lm          *backend.LibraryManager
 	nav         func(Route)
@@ -52,6 +53,7 @@ func (s *selectWidget) MinSize() fyne.Size {
 
 func NewAlbumsPage(title string, sortOrder string, lm *backend.LibraryManager, im *backend.ImageManager, nav func(Route)) *AlbumsPage {
 	a := &AlbumsPage{
+		title: title,
 		lm:    lm,
 		im:    im,
 		nav:   nav,
@@ -65,7 +67,6 @@ func NewAlbumsPage(title string, sortOrder string, lm *backend.LibraryManager, i
 	a.sortOrder = NewSelect(backend.AlbumSortOrders, nil)
 	a.sortOrder.Selected = sortOrder
 	a.sortOrder.OnChanged = a.onSortOrderChanged
-	sortVbox := container.NewVBox(layout.NewSpacer(), a.sortOrder, layout.NewSpacer())
 	iter := lm.AlbumsIter(backend.AlbumSortOrder(a.sortOrder.Selected))
 	a.grid = widgets.NewAlbumGrid(iter, im, false /*showYear*/)
 	a.grid.OnPlayAlbum = a.onPlayAlbum
@@ -73,7 +74,14 @@ func NewAlbumsPage(title string, sortOrder string, lm *backend.LibraryManager, i
 	a.grid.OnShowAlbumPage = a.onShowAlbumPage
 	a.searcher = widgets.NewSearcher()
 	a.searcher.OnSearched = a.OnSearched
+	a.createContainer()
+
+	return a
+}
+
+func (a *AlbumsPage) createContainer() {
 	searchVbox := container.NewVBox(layout.NewSpacer(), a.searcher.Entry, layout.NewSpacer())
+	sortVbox := container.NewVBox(layout.NewSpacer(), a.sortOrder, layout.NewSpacer())
 	a.container = container.NewBorder(
 		container.NewHBox(widgets.NewHSpace(9), a.titleDisp, sortVbox, layout.NewSpacer(), searchVbox, widgets.NewHSpace(15)),
 		nil,
@@ -81,6 +89,29 @@ func NewAlbumsPage(title string, sortOrder string, lm *backend.LibraryManager, i
 		nil,
 		a.grid,
 	)
+}
+
+func restoreAlbumsPage(saved *savedAlbumsPage) *AlbumsPage {
+	a := &AlbumsPage{
+		title: saved.title,
+		lm:    saved.lm,
+		im:    saved.im,
+		nav:   saved.nav,
+	}
+	a.ExtendBaseWidget(a)
+
+	a.titleDisp = widget.NewRichTextWithText(a.title)
+	a.titleDisp.Segments[0].(*widget.TextSegment).Style = widget.RichTextStyle{
+		SizeName: theme.SizeNameHeadingText,
+	}
+	a.sortOrder = NewSelect(backend.AlbumSortOrders, nil)
+	a.sortOrder.Selected = saved.sortOrder
+	a.sortOrder.OnChanged = a.onSortOrderChanged
+	a.grid = widgets.NewAlbumGridFromState(saved.gridState)
+	a.searcher = widgets.NewSearcher()
+	a.searcher.OnSearched = a.OnSearched
+	a.createContainer()
+
 	return a
 }
 
@@ -114,6 +145,17 @@ func (a *AlbumsPage) Reload() {
 	}
 }
 
+func (a *AlbumsPage) Save() SavedPage {
+	return &savedAlbumsPage{
+		title:     a.title,
+		lm:        a.lm,
+		im:        a.im,
+		nav:       a.nav,
+		sortOrder: a.sortOrder.Selected,
+		gridState: a.grid.SaveToState(),
+	}
+}
+
 func (a *AlbumsPage) doSearch(query string) {
 	if a.searchGrid == nil {
 		a.searchGrid = widgets.NewAlbumGrid(a.lm.SearchIter(query), a.im, false /*showYear*/)
@@ -153,3 +195,16 @@ func (a *AlbumsPage) CreateRenderer() fyne.WidgetRenderer {
 	a.ExtendBaseWidget(a)
 	return widget.NewSimpleRenderer(a.container)
 }
+
+type savedAlbumsPage struct {
+	title     string
+	lm        *backend.LibraryManager
+	im        *backend.ImageManager
+	nav       func(Route)
+	sortOrder string
+	gridState widgets.AlbumGridState
+}
+
+func (s *savedAlbumsPage) Restore() Page {
+	return restoreAlbumsPage(s)
+}

ui/browsing/artistpage.go

@@ -57,6 +57,15 @@ func (a *ArtistPage) Reload() {
 	a.loadAsync()
 }
 
+func (a *ArtistPage) Save() SavedPage {
+	return &savedArtistPage{
+		artistID: a.artistID,
+		sm:       a.sm,
+		im:       a.im,
+		nav:      a.nav,
+	}
+}
+
 func (a *ArtistPage) onPlayAlbum(albumID string) {
 	if a.OnPlayAlbum != nil {
 		a.OnPlayAlbum(albumID, 0)
@@ -88,3 +97,14 @@ func (a *ArtistPage) CreateRenderer() fyne.WidgetRenderer {
 	a.ExtendBaseWidget(a)
 	return widget.NewSimpleRenderer(a.container)
 }
+
+type savedArtistPage struct {
+	artistID string
+	sm       *backend.ServerManager
+	im       *backend.ImageManager
+	nav      func(Route)
+}
+
+func (s *savedArtistPage) Restore() Page {
+	return NewArtistPage(s.artistID, s.sm, s.im, s.nav)
+}

ui/browsing/browsingpane.go

@@ -2,6 +2,7 @@ package browsing
 
 import (
 	"image/color"
+	"log"
 	"supersonic/backend"
 
 	"fyne.io/fyne/v2"
@@ -16,10 +17,15 @@ import (
 type Page interface {
 	fyne.CanvasObject
 
+	Save() SavedPage
 	Reload()
 	Route() Route
 }
 
+type SavedPage interface {
+	Restore() Page
+}
+
 type CanPlayAlbum interface {
 	SetPlayAlbumCallback(func(albumID string, startingTrack int))
 }
@@ -42,7 +48,7 @@ type BrowsingPane struct {
 	forward    *widget.Button
 	back       *widget.Button
 	reload     *widget.Button
-	history    []Page
+	history    []SavedPage
 	historyIdx int
 
 	pageContainer *fyne.Container
@@ -67,8 +73,9 @@ func NewBrowsingPane(app *backend.App) *BrowsingPane {
 }
 
 func (b *BrowsingPane) SetPage(p Page) {
-	if b.doSetPage(p) {
+	oldPage := b.curPage
-		b.addPageToHistory(p)
+	if b.doSetPage(p) && oldPage != nil {
+		b.addPageToHistory(oldPage, true)
 	}
 }
 
@@ -99,13 +106,19 @@ func (b *BrowsingPane) onSongChange(song *subsonic.Child) {
 	}
 }
 
-func (b *BrowsingPane) addPageToHistory(p Page) {
+func (b *BrowsingPane) addPageToHistory(p Page, truncate bool) {
+	if truncate {
 		// allow garbage collection of pages that will be removed from the history
 		for i := b.historyIdx; i < len(b.history); i++ {
 			b.history[i] = nil
 		}
 		b.history = b.history[:b.historyIdx]
-	b.history = append(b.history, p)
+	}
+	if b.historyIdx < len(b.history) {
+		b.history[b.historyIdx] = p.Save()
+	} else {
+		b.history = append(b.history, p.Save())
+	}
 	b.historyIdx++
 }
 
@@ -116,16 +129,19 @@ func (b *BrowsingPane) goHome() {
 }
 
 func (b *BrowsingPane) GoBack() {
-	if b.historyIdx > 1 {
+	log.Printf("goBack called! historyIdx=%d, len=%d", b.historyIdx, len(b.history))
-		b.historyIdx -= 1
+	if b.historyIdx > 0 {
-		b.doSetPage(b.history[b.historyIdx-1])
+		b.addPageToHistory(b.curPage, false)
+		b.historyIdx -= 2
+		b.doSetPage(b.history[b.historyIdx].Restore())
 	}
 }
 
 func (b *BrowsingPane) GoForward() {
-	if b.historyIdx < len(b.history) {
+	log.Printf("goForward called! historyIdx=%d, len=%d", b.historyIdx, len(b.history))
-		b.historyIdx++
+	if b.historyIdx < len(b.history)-1 {
-		b.doSetPage(b.history[b.historyIdx-1])
+		b.addPageToHistory(b.curPage, false)
+		b.doSetPage(b.history[b.historyIdx].Restore())
 	}
 }
 

ui/browsing/genrepage.go

@@ -51,6 +51,12 @@ func NewGenrePage(genre string, lm *backend.LibraryManager, im *backend.ImageMan
 	g.grid.OnShowAlbumPage = g.onShowAlbumPage
 	g.searcher = widgets.NewSearcher()
 	g.searcher.OnSearched = g.OnSearched
+	g.createContainer()
+
+	return g
+}
+
+func (g *GenrePage) createContainer() {
 	searchVbox := container.NewVBox(layout.NewSpacer(), g.searcher.Entry, layout.NewSpacer())
 	g.container = container.NewBorder(
 		container.NewHBox(widgets.NewHSpace(9), g.titleDisp, layout.NewSpacer(), searchVbox, widgets.NewHSpace(15)),
@@ -59,6 +65,26 @@ func NewGenrePage(genre string, lm *backend.LibraryManager, im *backend.ImageMan
 		nil,
 		g.grid,
 	)
+}
+
+func restoreGenrePage(saved *savedGenrePage) *GenrePage {
+	g := &GenrePage{
+		genre: saved.genre,
+		lm:    saved.lm,
+		im:    saved.im,
+		nav:   saved.nav,
+	}
+	g.ExtendBaseWidget(g)
+
+	g.titleDisp = widget.NewRichTextWithText(g.genre)
+	g.titleDisp.Segments[0].(*widget.TextSegment).Style = widget.RichTextStyle{
+		SizeName: theme.SizeNameHeadingText,
+	}
+	g.grid = widgets.NewAlbumGridFromState(saved.gridState)
+	g.searcher = widgets.NewSearcher()
+	g.searcher.OnSearched = g.OnSearched
+	g.createContainer()
+
 	return g
 }
 
@@ -83,6 +109,16 @@ func (g *GenrePage) Reload() {
 	}
 }
 
+func (g *GenrePage) Save() SavedPage {
+	return &savedGenrePage{
+		genre:     g.genre,
+		lm:        g.lm,
+		im:        g.im,
+		nav:       g.nav,
+		gridState: g.grid.SaveToState(),
+	}
+}
+
 func (a *GenrePage) onPlayAlbum(albumID string) {
 	if a.OnPlayAlbum != nil {
 		a.OnPlayAlbum(albumID, 0)
@@ -125,3 +161,15 @@ func (g *GenrePage) doSearch(query string) {
 	g.container.Objects[0] = g.searchGrid
 	g.Refresh()
 }
+
+type savedGenrePage struct {
+	genre     string
+	lm        *backend.LibraryManager
+	im        *backend.ImageManager
+	nav       func(Route)
+	gridState widgets.AlbumGridState
+}
+
+func (s *savedGenrePage) Restore() Page {
+	return restoreGenrePage(s)
+}

ui/widgets/albumgrid.go

@@ -22,7 +22,12 @@ type AlbumIterator interface {
 type AlbumGrid struct {
 	widget.BaseWidget
 
+	AlbumGridState
+
 	grid *widget.GridWrapList
+}
+
+type AlbumGridState struct {
 	albums   []*subsonic.AlbumID3
 	iter     AlbumIterator
 	fetching bool
@@ -33,16 +38,20 @@ type AlbumGrid struct {
 	OnPlayAlbum      func(string)
 	OnShowAlbumPage  func(string)
 	OnShowArtistPage func(string)
+
+	scrollPos float32
 }
 
 var _ fyne.Widget = (*AlbumGrid)(nil)
 
 func NewFixedAlbumGrid(albums []*subsonic.AlbumID3, fetch ImageFetcher, showYear bool) *AlbumGrid {
 	ag := &AlbumGrid{
+		AlbumGridState: AlbumGridState{
 			albums:       albums,
 			done:         true,
 			imageFetcher: fetch,
 			showYear:     showYear,
+		},
 	}
 	ag.ExtendBaseWidget(ag)
 	ag.createGridWrapList()
@@ -51,8 +60,10 @@ func NewFixedAlbumGrid(albums []*subsonic.AlbumID3, fetch ImageFetcher, showYear
 
 func NewAlbumGrid(iter AlbumIterator, fetch ImageFetcher, showYear bool) *AlbumGrid {
 	ag := &AlbumGrid{
+		AlbumGridState: AlbumGridState{
 			iter:         iter,
 			imageFetcher: fetch,
+		},
 	}
 	ag.ExtendBaseWidget(ag)
 
@@ -63,6 +74,22 @@ func NewAlbumGrid(iter AlbumIterator, fetch ImageFetcher, showYear bool) *AlbumG
 	return ag
 }
 
+func (ag *AlbumGrid) SaveToState() AlbumGridState {
+	s := ag.AlbumGridState
+	s.scrollPos = ag.grid.GetScrollOffset()
+	return s
+}
+
+func NewAlbumGridFromState(state AlbumGridState) *AlbumGrid {
+	log.Printf("restoring album grid from state: %+v", state)
+	ag := &AlbumGrid{AlbumGridState: state}
+	ag.ExtendBaseWidget(ag)
+	ag.createGridWrapList()
+	ag.Refresh()
+	ag.grid.ScrollToOffset(state.scrollPos)
+	return ag
+}
+
 func (ag *AlbumGrid) Clear() {
 	ag.albums = nil
 	ag.done = true