this - Activity context
getApplicationContext() - Application context
個々に面白いことが書いてあった
http://bokukoko.hatenablog.com/entry/2014/05/08/Android_%E3%81%A7_Context_%E3%82%92%E6%B8%A1%E3%81%95%E3%81%AA%E3%81%8F%E3%81%A6%E3%82%82_getString_%E3%82%84Shared_Preference_%E3%82%92%E4%BD%BF%E3%81%88%E3%82%8B%E3%82%88%E3%81%86%E3%81%AB%E3%81%99
要はiOSっぽくグローバル変数を持たせる方法らしい
ApplicationController.java
public class ApplicationController extends Application { private static ApplicationController sInstance; @Override public void onCreate() { super.onCreate(); sInstance = this; } public static synchronized ApplicationController getInstance() { return sInstance; } }