toggleTheme method
void
toggleTheme()
Implementation
void toggleTheme() {
//var theme = Get.isDarkMode? ThemeData.light(): ThemeData.dark();
//Get.changeTheme(theme);
_isBrightnessDark = !_isBrightnessDark;
sharedPreferences.setBool('isDark', _isBrightnessDark);
update();
}