我無法通過藍牙發送數據

Question

我在Android Studio中編寫了應用程序，它必須在Arduino Pro Mini上發送1。數據已發送但未達到Arduino。我通過藍牙終端檢查了Arduino，一切正常，所以問題出在代碼中。哪裏不對？

package com.example.niko.motoco; 

import android.app.Activity; 
import android.bluetooth.BluetoothAdapter; 
import android.bluetooth.BluetoothDevice; 
import android.bluetooth.BluetoothSocket; 
import android.content.Intent; 
import android.os.Bundle; 
import android.support.design.widget.Snackbar; 
import android.support.v7.app.AppCompatActivity; 
import android.support.v7.widget.Toolbar; 
import android.util.Log; 
import android.view.View; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.widget.Button; 
import android.widget.TextView; 
import android.widget.Toast; 

import java.io.IOException; 
import java.io.OutputStream; 
import java.util.UUID; 

public class MainActivity extends AppCompatActivity { 

    BluetoothAdapter btAdapter = null ; 
    BluetoothDevice btDevice = null; 
    BluetoothSocket btSocket = null; 

    final String LOG_TAG = "myLogs"; 
    Button btConnect, btSend; 
    public TextView checkText; 

    private static final int REQUEST_ENABLE_BT = 1; 
    private static final int CONNECTEDdevice = 2; 

    Boolean connection = false; 
    private static String MAC = null; 
    UUID my_UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb"); 
    private ConnectedThread MyThread = null; 


    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 
     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     setSupportActionBar(toolbar); 

     checkText = (TextView) findViewById(R.id.checkText); 
     btConnect = (Button)findViewById(R.id.btConnect); 
     btSend = (Button)findViewById(R.id.btSend); 

     btAdapter = BluetoothAdapter.getDefaultAdapter(); 
     if (btAdapter == null) { 
      Toast.makeText(getApplicationContext(),"Device does not support Bluetooth",Toast.LENGTH_LONG).show(); 
     } else if (!btAdapter.isEnabled()) { 
      Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); 
      startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT); 
     } 


     btConnect.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       if (connection) { 
        // disconnect 
        try { 
         btSocket.close(); 
         connection = false; 
         btConnect.setText("Connect"); 
         Toast.makeText(getApplicationContext(),"Bluetooht is disconnected:",Toast.LENGTH_LONG).show(); 
        } catch (IOException error) { 
         Toast.makeText(getApplicationContext(),"Error;" + error,Toast.LENGTH_LONG).show(); 
        } 
       } else { 
        // connect 
        Intent ListDevices = new Intent(MainActivity.this, ListDevices.class); 
        startActivityForResult(ListDevices,CONNECTEDdevice); 
       } 

      } 
     }); 

     btSend.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       MyThread.write((byte) 1); 
       Toast.makeText(getApplicationContext(),"Sending 1",Toast.LENGTH_LONG).show(); 
      } 
     }); 


    } 

    @Override 
    protected void onActivityResult(int requestCode, int resultCode, Intent data) { 
     //super.onActivityResult(requestCode, resultCode, data); 
     switch (requestCode) { 
      case REQUEST_ENABLE_BT: 
       if(resultCode == Activity.RESULT_OK) { 
        Toast.makeText(getApplicationContext(),"bluetooth is activated",Toast.LENGTH_LONG).show(); 
       } else { 
        Toast.makeText(getApplicationContext(),"bluetooth is not activated",Toast.LENGTH_LONG).show(); 
        finish(); 
       } 
       break; 

      case CONNECTEDdevice : 
       if (resultCode == Activity.RESULT_OK) { 
        MAC = data.getExtras().getString(ListDevices.MACaddress); 

        btDevice = btAdapter.getRemoteDevice(MAC); 

        try { 
         btSocket = btDevice.createRfcommSocketToServiceRecord(my_UUID); 

         btSocket.connect(); 

         connection = true; 

         btConnect.setText("Disconnect"); 

         Toast.makeText(getApplicationContext(),"MAC of connected device:" + MAC,Toast.LENGTH_LONG).show(); 

         MyThread = new ConnectedThread(btSocket); 
         //MyThread.start(); 

        } catch (IOException error) { 
         connection = false; 
         Toast.makeText(getApplicationContext(),"Error:" + error,Toast.LENGTH_LONG).show(); 
        } 

       }else { 
        Toast.makeText(getApplicationContext(),"didn't get MAC",Toast.LENGTH_LONG).show(); 

       } 

     } 
    } 

    private class ConnectedThread extends Thread { 
     private final BluetoothSocket btSocket2; 
     private final OutputStream OutStream; 

     public ConnectedThread(BluetoothSocket socket) { 
      btSocket2 = socket; 
      OutputStream tmpOut = null; 


      try { 
       tmpOut = socket.getOutputStream(); 
      } catch (IOException e) { } 

      OutStream = tmpOut; 
     } 


     public void write(byte bytes) { 
      try { 
       OutStream.write(bytes); 
      } catch (IOException e) { } 
     } 


     public void cancel() { 
      try { 
       btSocket2.close(); 
      } catch (IOException e) { } 
     } 
    } 



} 

Answer 1

怎麼了？至少是2個代碼是錯誤的：

try { 
    tmpOut = socket.getOutputStream(); 
} catch (IOException e) { } 

及更高版本：

try { 
    OutStream.write(bytes); 
} catch (IOException e) { } 

當出現錯誤時，你捕獲該異常默默和適度寬鬆的一切機會，以確定根本原因。

更改代碼是這樣的：

try { 
    tmpOut = socket.getOutputStream(); 
} catch (IOException e) { 
    Log.(TAG, "Fail to get socket output stream" ,e); 
} 

及更高版本：

try { 
    OutStream.write(bytes); 
} catch (IOException e) { 
    Log.(TAG, "Fail to write on socket output stream" ,e); 
} 

然後重新運行你的代碼，並期待在logcat的。你可能會看到你的問題的原因。