Preferences API

Learn how to use Fyne’s Preferences API to store and retrieve user settings, such as theme choices, window size, or custom app configurations.

Usage

Show Code

package main

import (
  "fmt"

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

func main() {
  // Use app.NewWithID so preferences persist across runs
  a := app.NewWithID("com.example.preferences")
  w := a.NewWindow("Preferences API")

  // Get Preferences API
  prefs := a.Preferences()

  // Load stored value or default
  username := prefs.StringWithFallback("username", "Guest")

  label := widget.NewLabel("Hello, " + username)

  entry := widget.NewEntry()
  entry.SetPlaceHolder("Enter your name")
  entry.SetText(username)

  saveBtn := widget.NewButton("Save", func() {
    name := entry.Text
    prefs.SetString("username", name) // ✅ Save to preferences
    label.SetText("Hello, " + name)
    fmt.Println("Saved username:", name)
  })

  clearBtn := widget.NewButton("Clear", func() {
    prefs.RemoveValue("username") // ❌ Remove saved key
    label.SetText("Hello, Guest")
    fmt.Println("Cleared username")
  })

  w.SetContent(container.NewVBox(
    label,
    entry,
    saveBtn,
    clearBtn,
  ))

  w.Resize(fyne.NewSize(300, 200))
  w.ShowAndRun()
}