[Flutter / 기본] Pull To Refresh

Flutter 의 Pull To Refresh는 RefreshIndicator를 사용한다.

onRefresh 속성에 Pull 동작시 콜백되는 함수를 정의한다.

child: RefreshIndicator(
    onRefresh: _startScan,
    child: ListView.builder(
      itemCount: _foundBleUARTDevices.length,
      itemBuilder: (BuildContext context, int index) => Card(
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(16.0),
        ),
        elevation: 4.0,
        child: ListTile(
          dense: true,
          enabled: !(!_connected && _scanning),
          trailing: GestureDetector(
            behavior: HitTestBehavior.translucent,
            onTap: () {
              //(!_connected && _scanning) || (!_scanning && _connected)? (){}: onConnectDevice(index);
            },
            child: Container(
              width: 48,
              height: 48,
              padding: const EdgeInsets.symmetric(vertical: 4.0),
              alignment: Alignment.center,
              child: const Icon(Icons.add_link),
            ),
          ),
          subtitle: Text(_foundBleUARTDevices[index].id),
          title: Text("${_foundBleUARTDevices[index].name}",style: TextStyle(fontWeight: FontWeight.bold, fontSize: 20)),
        ),
      ),
    ),
  ),

콜백되는 함수에서 Refresh 처리를 수행하도록 하며,

콜백되는 함수는 Future 를 return하도록 작성되어야 한다.

Future<void> _startScan() async {
    if (Platform.isAndroid) {
      if(await checkIfPermissionGranted()) {
        if(_scanning==true) {
          _stopScan();
        }
          _foundBleUARTDevices = [];
          _scanning = true;
          setState(() {});
          _scanStream = flutterReactiveBle.scanForDevices(
            withServices: [_UART_UUID]).listen((device) {
            //withServices: []).listen((device) {
              if (_foundBleUARTDevices.every((element) => element.id != device.id)) {
                if(device.name.contains('ACRO')) {
                  _foundBleUARTDevices.add(device);
                  print("${device.name}\n");
                  setState(() {});
                }
              }
            }, onError: (Object error) {
              print("${_logTexts}ERROR while scanning:$error \n");
            }
          );
      } else {
        await showNoPermissionDialog();
        openAppSettings();
      }
    }
    return Future<void>.value();
  }