如何从另一个活动更改一个活动的背景颜色？

Question

I have MainActivty and SettingsActivity , when I press a button in my SettingsActivity I want the background color of the MainActivity to change.

How do I achieve this? Sorry if this question is a bit dumb, I recently started out and I'm a bit lost.

Answer 1

Save the color Hex as String or Integer of Color to SharedPreferences and get it on activity @onCreate()

SharedPreferences preferences= context.getSharedPreferences(
      "SharedPrefName", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("SharedPrefKey","#FF0000" /*change this to what you want*/);
editor.apply();

then in activity get color

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
String color = preferences.getString("SharedPrefKey", "#000000");