问在Android中打开摄像头时检查NFC是否处于活动状态。

EN

// Listen to NFC setting changes
    this.registerReceiver(mReceiver, filter);
    }

    // Listen for NFC being turned on while in the App
    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            final String action = intent.getAction();

            if (action.equals(NfcAdapter.ACTION_ADAPTER_STATE_CHANGED)) {
                final int state = intent.getIntExtra(NfcAdapter.EXTRA_ADAPTER_STATE,
                        NfcAdapter.STATE_OFF);
                switch (state) {
                    case NfcAdapter.STATE_OFF:
                    // Tell the user to turn NFC on if App requires it
                        break;
                    case NfcAdapter.STATE_TURNING_OFF:
                        break;
                    case NfcAdapter.STATE_ON:
                        // Enabled NFC;
                        break;
                    case NfcAdapter.STATE_TURNING_ON:
                        break;
                }
            }
        }
    };