code: public static void onCreate(Context context) {
          SharedPreferences pref = context.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
          Editor editor = pref.edit();
          // If it is the first launch, save the date in shared preference.
          if (pref.getLong(KEY_INSTALL_DATE, 0) == 0L) {
              storeInstallDate(context, editor);
          }
          // Increment launch times
          int launchTimes = pref.getInt(KEY_LAUNCH_TIMES, 0);
          launchTimes++;
          editor.putInt(KEY_LAUNCH_TIMES, launchTimes);
          log("Launch times; " + launchTimes);
  
          editor.apply();
  
          mInstallDate = new Date(pref.getLong(KEY_INSTALL_DATE, 0));
          mLaunchTimes = pref.getInt(KEY_LAUNCH_TIMES, 0);
          mOptOut = pref.getBoolean(KEY_OPT_OUT, false);
          mAskLaterDate = new Date(pref.getLong(KEY_ASK_LATER_DATE, 0));
  
          printStatus(context);
      }
docs: Call this API when the launcher activity is launched.<br>
  It is better to call this API in onCreate() of the launcher activity.
  @param context Context