some tweaks to ui theming for Fyne 2.3

ui/browsing/browsingpane.go

@@ -1,10 +1,10 @@
 package browsing
 
 import (
-	"image/color"
 	"supersonic/backend"
 	"supersonic/ui/controller"
 	"supersonic/ui/layouts"
+	myTheme "supersonic/ui/theme"
 
 	"fyne.io/fyne/v2"
 	"fyne.io/fyne/v2/canvas"
@@ -69,7 +69,9 @@ func NewBrowsingPane(app *backend.App) *BrowsingPane {
 	b.app.PlaybackManager.OnSongChange(b.onSongChange)
 	b.pageContainer = container.NewMax(
 		// TODO: get this color into the theme
-		canvas.NewRectangle(color.RGBA{R: 24, G: 24, B: 40, A: 255}),
+		canvas.NewRectangle(fyne.CurrentApp().Settings().Theme().Color(
+			myTheme.ColorNamePageBackground, theme.VariantDark,
+		)),
 		layout.NewSpacer())
 	b.settingsBtn = widget.NewButtonWithIcon("", theme.SettingsIcon(), func() {
 		p := widget.NewPopUpMenu(b.settingsMenu,

ui/theme/theme.go

@@ -0,0 +1,40 @@
+package theme
+
+import (
+	"image/color"
+
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/theme"
+)
+
+const ColorNamePageBackground fyne.ThemeColorName = "PageBackground"
+
+type MyTheme struct{}
+
+var _ fyne.Theme = (*MyTheme)(nil)
+
+func (m MyTheme) Color(name fyne.ThemeColorName, variant fyne.ThemeVariant) color.Color {
+	switch name {
+	case ColorNamePageBackground:
+		return color.RGBA{R: 20, G: 20, B: 20, A: 255}
+	case theme.ColorNameBackground:
+		return color.RGBA{R: 40, G: 40, B: 40, A: 255}
+	case theme.ColorNameScrollBar:
+		return theme.DarkTheme().Color(theme.ColorNameForeground, variant)
+	case theme.ColorNameButton:
+		return theme.DarkTheme().Color(theme.ColorNameInputBackground, variant)
+	}
+	return theme.DarkTheme().Color(name, variant)
+}
+
+func (m MyTheme) Icon(name fyne.ThemeIconName) fyne.Resource {
+	return theme.DefaultTheme().Icon(name)
+}
+
+func (m MyTheme) Font(style fyne.TextStyle) fyne.Resource {
+	return theme.DefaultTheme().Font(style)
+}
+
+func (m MyTheme) Size(name fyne.ThemeSizeName) float32 {
+	return theme.DefaultTheme().Size(name)
+}

ui/widgets/listheader.go

@@ -42,7 +42,7 @@ func NewListHeader(cols []ListColumn, layout *layouts.ColumnsLayout) *ListHeader
 	for i, _ := range l.columnVisible {
 		l.columnVisible[i] = true
 	}
-	l.container = container.NewMax(canvas.NewRectangle(theme.ButtonColor()), l.columnsContainer)
+	l.container = container.NewMax(canvas.NewRectangle(theme.BackgroundColor()), l.columnsContainer)
 	l.ExtendBaseWidget(l)
 	l.buildColumns()
 	return l

ui/widgets/nowplayingcard.go

@@ -36,7 +36,7 @@ func NewNowPlayingCard() *NowPlayingCard {
 	n.cover.SetMinSize(fyne.NewSize(85, 85))
 	n.cover.FillMode = canvas.ImageFillContain
 
-	n.c = container.NewBorder(nil, nil, container.New(&layouts.CenterPadLayout{PadLeftRight: 3, PadTopBottom: 5}, n.cover), nil,
+	n.c = container.NewBorder(nil, nil, n.cover, nil,
 		container.New(&layouts.VboxCustomPadding{ExtraPad: -12}, n.trackName, n.artistName, n.albumName))
 	return n
 }