How to send a character(char) via bluetooth

Question

I’d like to send the number 1 via bluetooth on android, already made the part of connection to send
- this is the source code

    public void  conectar(ProgressBar loading, BluetoothSocket socket) { 
        loading.Visibility = Android.Views.ViewStates.Visible;      

        try {

            socket.Connect();

        }
        catch (Exception)
        {
            loading.Visibility = Android.Views.ViewStates.Gone;
            Toast.MakeText(this, "Não foi possivel conectar", ToastLength.Long).Show();


        }
        try
        {
            var output = socket.InputStream;
            loading.Visibility = Android.Views.ViewStates.Gone;

            Toast.MakeText(this, "pode escrever", ToastLength.Long).Show();
            byte[] buffer = new byte[1024];

            output.Write(buffer, 1, 1);

        }
        catch (Exception) { 
        Toast.MakeText(this, "Não foi possivel enviar a mensagem", ToastLength.Long).Show();
        loading.Visibility = Android.Views.ViewStates.Gone;
        }





    }

    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        SetContentView(Resource.Layout.tela);

        BluetoothAdapter adaptador = BluetoothAdapter.DefaultAdapter; // procura o adap. bluetooth 

        TextView aparelho1 = FindViewById<TextView>(Resource.Id.aparelho1);
        TextView aparelhoconfig = FindViewById<TextView>(Resource.Id.aparelhoconfig);
        TextView aparelho2 = FindViewById<TextView>(Resource.Id.aparelho2);
        TextView aparelho2config = FindViewById<TextView>(Resource.Id.aparelho2config);
        RelativeLayout layout1 = FindViewById<RelativeLayout>(Resource.Id.layoutaparelho1);
        RelativeLayout layout2 = FindViewById<RelativeLayout>(Resource.Id.layoutaparelho2);
        ProgressBar loading = FindViewById<ProgressBar>(Resource.Id.progressBar1);

        loading.Visibility = Android.Views.ViewStates.Gone;

        if (adaptador == null)
        {
            Toast.MakeText(this, "Esse aparelho não tem bluetooth", ToastLength.Long).Show();
        }
        else {
            if (adaptador.IsEnabled == true)
            {
                ICollection<BluetoothDevice> aparelhos = adaptador.BondedDevices;
                BluetoothDevice[] apa = new BluetoothDevice[aparelhos.Count];
                ParcelUuid[] chaves;
                BluetoothSocket[] socket = new BluetoothSocket[aparelhos.Count];
                int i = 0;


                foreach (BluetoothDevice aparelho in aparelhos)
                {
                    apa[i] = aparelho;
                    chaves = aparelho.GetUuids();
                    socket[i] = aparelho.CreateInsecureRfcommSocketToServiceRecord(chaves[i].Uuid);
                    i++;

                }
                if (apa.Length > 0)
                {

                    aparelho1.Append(apa[0].Name);
                    aparelhoconfig.Append(apa[0].Address);
                    /// <summary>
                    /// evento ao clicar no outro relative layout1
                    /// </summary>

                    layout1.Click += delegate
                    {
                        Toast.MakeText(this,"clicou",ToastLength.Short).Show();
                        conectar(loading,socket[0]);
                    };
                    //final

                    if (apa.Length > 1)
                    {
                        aparelho2.Append(apa[1].Name);
                        aparelhoconfig.Append(apa[1].Address);
                        /// <summary>
                        /// evento ao clicar no outro relative layout2
                        /// </summary>
                        layout2.Click += delegate
                        {


                        };
                        //final
                    }


                }




            }
            else {
                Toast.MakeText(this, "Ative o bluetooth para continuar", ToastLength.Long).Show();

            }



        }
    }`

Answer 1

When you connect with two (or more) devices, each will have one Bluetoothsocket connected. Basically you would have to use the Connectedthread passing as parameter your socket, and then the fun begins. See below:

ConnectedThread mConnectedThread = new ConnectedThread(socket);
mConnectedThread.start();

To read and write data, it is necessary to use read(byte[]) and write(byte[]). Below is a basic example of how you should use using two buttons:

    btnDesliga.setOnClickListener(new OnClickListener() {
      public void onClick(View v) {
        mConnectedThread.write("0");              
      }
    });

    btnLiga.setOnClickListener(new OnClickListener() {
      public void onClick(View v) {
        mConnectedThread.write("1");
      }
    });

Hugs.