Files and “preferences”

This page is honest about a removal. If you’re looking for SharedPreferences/UserDefaults, stop: in CrossFly that mechanism does not exist.

⚠️ Lightweight persistence has been removed

Settings.appSettings, appSecretKey, refresh() and the old “preferences” no longer exist — and there is no automatic write on exit. You write explicitly, at the right moment.

What to use instead

Key/value in SQLite (recommended for settings)

try (SqliteDb db = SqliteDb.open("app.db")) {
   db.exec("CREATE TABLE IF NOT EXISTS kv(k TEXT PRIMARY KEY, v TEXT)");
   db.execute("INSERT OR REPLACE INTO kv(k, v) VALUES(?, ?)", "tema", "escuro");
   String tema = db.queryString("SELECT v FROM kv WHERE k=?", "tema");   // null if absent
}

Simple file in Device.homeFolder

Device.homeFolder is the app’s base directory (varies by platform):

String path = Device.homeFolder + "config.json";

byte[] bytes = Utils.readBytes(path);   // ⚠️ null if the file does not exist
if (bytes != null) {
   String json = new String(bytes);
   // … parse …
}
// FileHandle (libGDX) for cases that need more control:
FileHandle fh = Utils.loadFile(path);   // null if not found

Best practices

• Write explicitly at the right points (when saving config, when leaving a screen) — nothing is persisted on its own.
• Prefer SQLite kv over a loose file for settings (transactional, queryable).
• Always check for null from Utils.readBytes/loadFile (the file may not exist).

Common mistakes

• Looking for Settings.appSettings/SharedPreferences — it was removed; it’s not coming back.
• Assuming an automatic write on close — there is none; write it yourself.
• Not handling null when reading a nonexistent file.

See also

• Persistence with SQLite