Custom Theme

Create and apply a custom theme in Fyne by overriding colors, fonts, and icons to match your app’s branding.

Usage

Show Code

package main

import (
  "image/color"

  "fyne.io/fyne/v2"
  "fyne.io/fyne/v2/app"
  "fyne.io/fyne/v2/container"
  "fyne.io/fyne/v2/theme"
  "fyne.io/fyne/v2/widget"
)

// MyTheme is a custom theme implementing fyne.Theme
type MyTheme struct{}

// -------- COLORS ----------
func (m MyTheme) Color(name fyne.ThemeColorName, variant fyne.ThemeVariant) color.Color {
  switch name {
  case theme.ColorNameBackground:
    // Set custom background (light gray)
    return color.NRGBA{R: 240, G: 240, B: 240, A: 255}
  case theme.ColorNameButton:
    // Custom button color (blue)
    return color.NRGBA{R: 52, G: 152, B: 219, A: 255}
  case theme.ColorNameDisabledButton:
    return color.NRGBA{R: 180, G: 180, B: 180, A: 255}
  case theme.ColorNameFocus:
    // Dark text
    return color.NRGBA{R: 33, G: 33, B: 33, A: 255}
  case theme.ColorNameDisabled:
    return color.NRGBA{R: 120, G: 120, B: 120, A: 255}
  }
  // Fallback → use default theme colors
  return theme.DefaultTheme().Color(name, variant)
}

// -------- ICONS ----------
func (m MyTheme) Icon(name fyne.ThemeIconName) fyne.Resource {
  switch name {
  case theme.IconNameConfirm:
    return theme.CancelIcon()
  }
  return theme.DefaultTheme().Icon(name)
}

// -------- FONTS ----------
func (m MyTheme) Font(style fyne.TextStyle) fyne.Resource {
  return theme.DefaultTheme().Font(style)
}

// -------- SIZES ----------
func (m MyTheme) Size(name fyne.ThemeSizeName) float32 {
  switch name {
  case theme.SizeNameText:
    return 18 // larger text
  case theme.SizeNamePadding:
    return 12 // more padding
  }
  return theme.DefaultTheme().Size(name)
}

func main() {
  a := app.New()
  w := a.NewWindow("Custom Theme Demo")

  // Apply our theme
  a.Settings().SetTheme(&MyTheme{})

  btn := widget.NewButton("Custom Themed Button", func() {})
  label := widget.NewLabel("Hello from custom theme!")
  entry := widget.NewEntry()
  entry.SetPlaceHolder("Type here...")

  w.SetContent(
    container.NewVBox(
      label,
      btn,
      entry,
      widget.NewButtonWithIcon("Confirm", theme.ConfirmIcon(), func() {}),
    ),
  )

  w.Resize(fyne.NewSize(400, 250))
  w.ShowAndRun()
}