// Obtain shared preferences.final prefs = await SharedPreferences.getInstance();// Save an integer value to 'counter' key.await prefs.setInt('counter', 10);// Save an boolean value to 'repeat' key.await prefs.setBool('repeat', true);// Save an double value to 'decimal' key.await prefs.setDouble('decimal', 1.5);// Save an String value to 'action' key.await prefs.setString('action', 'Start');// Save an list of strings to 'items' key.await prefs.setStringList('items', <String>['Earth', 'Moon', 'Sun']);// Try reading data from the 'counter' key. If it doesn't exist, returns null.final int? counter = prefs.getInt('counter');// Try reading data from the 'repeat' key. If it doesn't exist, returns null.final bool? repeat = prefs.getBool('repeat');// Try reading data from the 'decimal' key. If it doesn't exist, returns null.final double? decimal = prefs.getDouble('decimal');// Try reading data from the 'action' key. If it doesn't exist, returns null.final String? action = prefs.getString('action');// Try reading data from the 'items' key. If it doesn't exist, returns null.final List<String>? items = prefs.getStringList('items');