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我是 Android 开发人员的新手。我尝试创建一个简单的应用程序来打开和关闭 LED。然后，我将它安装在我的 Android 手机上。但是当我点击开或关按钮时，它说：

致命错误 - 在 onResume() 和 write:socket close 期间发生异常。

希望有人帮助我更改我的代码。

这是我的代码：

package com.example.ledonoff;

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

import com.example.ledonoff.R;

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.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Toast;


public class Main extends Activity {
 private static final String TAG = "Main";

  private static final int REQUEST_ENABLE_BT = 1;
  private BluetoothAdapter btAdapter = null;
  private BluetoothSocket btSocket = null;
  private OutputStream outStream = null;

  // Well known SPP UUID
  private static final UUID MY_UUID =
      UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

  // Insert your server's MAC address
  private static String address = "50:F5:20:42:7F:2B";


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
     Log.d(TAG, "In onCreate()");
    setContentView(R.layout.activity_main);

    btAdapter = BluetoothAdapter.getDefaultAdapter();
    checkBTState();
}
      public void buttonOn(View v) {
        sendData("1");
        Toast msg = Toast.makeText(getBaseContext(),"LED On", Toast.LENGTH_SHORT);
        msg.show();
      }
        public void buttonOff(View v) {
          sendData("0");
          Toast msg = Toast.makeText(getBaseContext(),"LED Off", Toast.LENGTH_SHORT);
          msg.show();
        }


 @Override
  public void onResume() {
    super.onResume();

    Log.d(TAG, "...In onResume - Attempting client connect...");

    // Set up a pointer to the remote node using it's address.
    BluetoothDevice device = btAdapter.getRemoteDevice(address);

    // Two things are needed to make a connection:
    //   A MAC address, which we got above.
    //   A Service ID or UUID.  In this case we are using the
    //     UUID for SPP.
    try {
      btSocket = device.createRfcommSocketToServiceRecord(MY_UUID);
    } catch (IOException e) {
      errorExit("Fatal Error", "In onResume() and socket create failed: " + e.getMessage() + ".");
    }

    // Discovery is resource intensive.  Make sure it isn't going on
    // when you attempt to connect and pass your message.
    btAdapter.cancelDiscovery();

    // Establish the connection.  This will block until it connects.
    Log.d(TAG, "...Connecting to Remote...");
    try {
      btSocket.connect();
      Log.d(TAG, "...Connection established and data link opened...");
    } catch (IOException e) {
      try {
        btSocket.close();
      } catch (IOException e2) {
        errorExit("Fatal Error", "In onResume() and unable to close socket during connection failure" + e2.getMessage() + ".");
      }
    }

    // Create a data stream so we can talk to server.
    Log.d(TAG, "...Creating Socket...");

    try {
      outStream = btSocket.getOutputStream();
    } catch (IOException e) {
      errorExit("Fatal Error", "In onResume() and output stream creation failed:" + e.getMessage() + ".");
    }
  }

  @Override
  public void onPause() {
    super.onPause();

    Log.d(TAG, "...In onPause()...");

    if (outStream != null) {
      try {
        outStream.flush();
      } catch (IOException e) {
        errorExit("Fatal Error", "In onPause() and failed to flush output stream: " + e.getMessage() + ".");
      }
    }

    try     {
      btSocket.close();
    } catch (IOException e2) {
      errorExit("Fatal Error", "In onPause() and failed to close socket." + e2.getMessage() + ".");
    }
  }

  private void checkBTState() {
    // Check for Bluetooth support and then check to make sure it is turned on

    // Emulator doesn't support Bluetooth and will return null
    if(btAdapter==null) {
      errorExit("Fatal Error", "Bluetooth Not supported. Aborting.");
    } else {
      if (btAdapter.isEnabled()) {
        Log.d(TAG, "...Bluetooth is enabled...");
      } else {
        //Prompt user to turn on Bluetooth
        Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
        startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
      }
    }
  }

  private void errorExit(String title, String message){
    Toast msg = Toast.makeText(getBaseContext(),
        title + " - " + message, Toast.LENGTH_SHORT);
    msg.show();
    finish();
  }

  private void sendData(String message) {
    byte[] msgBuffer = message.getBytes();

    Log.d(TAG, "...Sending data: " + message + "...");

    try {
      outStream.write(msgBuffer);
    } catch (IOException e) {
      String msg = "In onResume() and an exception occurred during write: " + e.getMessage();
      if (address.equals("00:00:00:00:00:00"))
        msg = msg + ".\n\nUpdate your server address from 00:00:00:00:00:00 to the correct address on line 37 in the java code";
      msg = msg +  ".\n\nCheck that the SPP UUID: " + MY_UUID.toString() + " exists on server.\n\n";

      errorExit("Fatal Error", msg);      
    }
  }

@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;
}

}

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1 回答 1

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我想这是因为您在连接 btSocket 时遇到异常，然后在异常处理程序中您捕获 btSocket.close() 的另一个异常（如果 connect() 失败，则无法关闭它）

于 2017-10-14T15:56:39.813 回答