Flutter：类型'Future<bool?>'不是类型'FutureOr<bool>'在类型转换中的子类型

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I'm new on the Flutter & working on the integration of POS printing machine in flutter & using the pos_printer_manager 包。

它显示在这个包的捕获部分有一个错误，即【替换代码0

& pointing out in this code

/// [writeBytes] let you write raw list int data into socket
  @override
  Future<ConnectionResponse> writeBytes(List<int> data,
      {bool isDisconnect: true}) async {
    try {
      if (!isConnected) {
        await connect();
      if (Platform.isAndroid || Platform.isIOS) {
        if ((await (bluetooth.isConnected as FutureOr<bool>))) {
          Uint8List message = Uint8List.fromList(data);
          PosPrinterManager.logger.warning("message.length ${message.length}");
          await bluetooth.writeBytes(message);
          if (isDisconnect) {
            await disconnect();
          return ConnectionResponse.success;
        return ConnectionResponse.printerNotConnected;
      //  else if (Platform.isIOS) {
      //   // var services = (await fbdevice.discoverServices());
      //   // var service = services.firstWhere((e) => e.isPrimary);
      //   // var charactor =
      //   //     service.characteristics.firstWhere((e) => e.properties.write);
      //   // await charactor?.write(data, withoutResponse: true);
      //   return ConnectionResponse.success;
      return ConnectionResponse.unsupport;
    } catch (e) {
      print("Error : $e");
      return ConnectionResponse.unknown;
This is due to bluetooth.isConnected as FutureOr<bool>.
So any big difference between Future<bool?> & FutureOr<bool> ?
Basically I faced type casting error in the package & I need a solution to handle this on the package side & how to manage the optional.


         android

ios


         flutter


         dart


         thermal-printer


        
         
         
          Ankush Lokhande
         
        
        
         发布于
         
         2022-12-29


        2
        
        个回答


          
           
           
            Abhi Tripathi
           
          
          
           发布于
           
           2022-12-29


         0
         
         人赞同


          
           根据你的发现，typecast是不需要的，它需要一个空检查
          
          if (Platform.isAndroid || Platform.isIOS) {
         bool? isConnected  = await bluetooth.isConnected;
        if (isConnected != null && isConnected!) {
          Uint8List message = Uint8List.fromList(data);
          PosPrinterManager.logger.warning("message.length ${message.length}");
          await bluetooth.writeBytes(message);
          if (isDisconnect) {
            await disconnect();
          return ConnectionResponse.success;
        return ConnectionResponse.printerNotConnected;