private int mNumSlots;


        final TelephonyManager tm =
                (TelephonyManager) getActivity().getSystemService(Context.TELEPHONY_SERVICE);
        mNumSlots = tm.getSimCount();


        for (int i = 0; i < mNumSlots; ++i) {
            final SubscriptionInfo sir = mSubscriptionManager.getActiveSubscriptionInfoForSimSlotIndex(i);  //當sir 為空時。說明那個卡槽沒卡，可以得到當前手機運營商

        }

 當sir 為空時。說明那個卡槽沒卡