[Android] get SharedPreferences name from its resource id

SharedPreferencesName.java

public static String getSharedPreferenceName(Context ctx, int prefResId) {
	String packageName = ctx.getApplicationContext().getPackageName();
	Resources res = ctx.getResources();
	String entryName = res.getResourceEntryName(prefResId);
	return packageName + "_" + entryName;
}