通过蓝牙传输字符串

Question

我们能够在文本视图中列出配对的蓝牙设备。该应用程序有两个EditText，一个接受字符串消息，另一个接受目标设备的MAC地址，另一个发送按钮将消息发送到目的地地址，但点击发送按钮时应用程序将关闭。请帮助我们。 提前致谢。          package com.example.javapoint;

     import android.os.Bundle;

 import android.app.Activity;  
  import android.util.Log;
   import android.view.Menu;  
   import android.view.View;

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

   import android.bluetooth.BluetoothAdapter;  
     import android.bluetooth.BluetoothDevice;  
     import android.bluetooth.BluetoothSocket;
   import android.content.Intent;  
    import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;  
    import android.view.View.OnClickListener;


   public class MainActivity extends Activity {
 TextView textview1;  
 UUID applicationUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

 private static final int REQUEST_ENABLE_BT = 1;  
 BluetoothAdapter btAdapter;   
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    textview1 = (TextView)findViewById(R.id.textView1);


    // Getting the Bluetooth adapter  
    btAdapter = BluetoothAdapter.getDefaultAdapter();  
    textview1.append("\nAdapter: " + btAdapter);  


        CheckBluetoothState();  

  }  

  /* It is called when an activity completes.*/  
  @Override  
  protected void onActivityResult(int requestCode, int resultCode, Intent data) {  
    super.onActivityResult(requestCode, resultCode, data);  
    if (requestCode == REQUEST_ENABLE_BT) {  
      CheckBluetoothState();  
    }  
  }  

  @Override  
  protected void onDestroy() {  
    super.onDestroy();  
  }  

  private void CheckBluetoothState() {  
    // Checks for the Bluetooth support and then makes sure it is turned on  
    // If it isn't turned on, request to turn it on  
    // List paired devices  
    if(btAdapter==null) {   
      textview1.append("\nBluetooth NOT supported. Aborting.");  
      return;  
    } else {  
      if (btAdapter.isEnabled()) {  
        textview1.append("\nBluetooth is enabled...");  

        // Listing paired devices  
        textview1.append("\nPaired Devices are:");  
        Set<BluetoothDevice> devices = btAdapter.getBondedDevices();  
        for (BluetoothDevice device : devices) {  
          textview1.append("\n  Device: " + device.getName() + ", " + device);  
        }  
      } else {  
        //Prompt user to turn on Bluetooth  
        Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);  
        startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);  
      }  
    }  


    Button sbtn=(Button)findViewById(R.id.btn2);
    final EditText et=(EditText)findViewById(R.id.message);
final String msg=et.getText().toString();
     final EditText et1=(EditText)findViewById(R.id.macaddress);
    final String mac=et1.getText().toString();
     sbtn.setOnClickListener(new OnClickListener()
        {




            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                 byte[] toSend = msg.getBytes();


                 try {

                     BluetoothDevice mBluetoothDevice =    btAdapter.getRemoteDevice(mac);
BluetoothSocket socket       =mBluetoothDevice.createInsecureRfcommSocketToServiceRecord(applicationUUID);
                        socket.connect();
    OutputStream mmOutStream = socket.getOutputStream();
                        mmOutStream.write(toSend);
                        socket.close();
    // Your Data is sent to  BT connected paired device ENJOY.
                    } catch (IOException e) {

                    }
            }
        });


    }






@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

  }