Android Studio 入门：（七） 安卓蓝牙聊天功能的实现

目录

1. 清单文件注册权限

2. 在文件res/values/strings.xml里，添加程序运行过程中的状态描述文本及配色代码等

3.修改聊天界面布局文件

4.用于蓝牙会话的服务组件ChatService

5.建立选择蓝牙设备的布局文件 device_list.xml

6.新建Activity组件DeviceList，实现选取与之会话的蓝牙设备

7. 界面程序weixinFragment.java

8.源码地址

---

1. 清单文件注册权限

2. 在文件res/values/strings.xml里，添加程序运行过程中的状态描述文本及配色代码等

    BlueTooth_Chat
    蓝牙聊天
    底部图标
    微信
    朋友
    通讯录
    设置

    发送
    你没有链接一个设备
    蓝牙不可用，离开聊天室
    链接中...
    连接到：
    无链接
    蓝牙设备搜索中...
    选择一个好友链接
    没有配对好友
    附近没有发现好友
    已配对好友
    其它可连接好友
    搜索好友
    我的好友
    设置在线
    退出
    开始聊天
    结束聊天

    
    Hello blank fragment

3.修改聊天界面布局文件

4.用于蓝牙会话的服务组件ChatService

package com.e.bluetooth_chat;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;

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

public class ChatService {
    //本应用的主Activity组件名称
    private static final String NAME = "BlueToothChat";
    // UUID：通用唯一识别码,是一个128位长的数字，一般用十六进制表示
    //算法的核心思想是结合机器的网卡、当地时间、一个随机数来生成
    //在创建蓝牙连接
    private static final UUID MY_UUID = UUID.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66");
    private final BluetoothAdapter mAdapter;
    private final Handler mHandler;
    private AcceptThread mAcceptThread;
    private ConnectThread mConnectThread;
    private ConnectedThread mConnectedThread;
    private int mState;
    public static final int STATE_NONE = 0;
    public static final int STATE_LISTEN = 1;
    public static final int STATE_CONNECTING = 2;
    public static final int STATE_CONNECTED = 3;

    //构造方法，接收UI主线程传递的对象
    public ChatService(Context context,Handler handler){
        //构造方法完成蓝牙对象的创建
        mAdapter = BluetoothAdapter.getDefaultAdapter();
        mState = STATE_NONE;
        mHandler = handler;
    }

    private synchronized void setState(int state){
        mState = state;
        mHandler.obtainMessage(weixinFragment.MESSAGE_STATE_CHANGE, state, -1).sendToTarget();
    }

    public synchronized int getState(){
        return mState;
    }

    public synchronized void start(){
        if (mConnectThread != null) {
            mConnectThread.cancel();
            mConnectThread = null;
        }
        if (mConnectedThread != null) {
            mConnectedThread.cancel();
            mConnectedThread = null;
        }
        if (mAcceptThread == null) {
            mAcceptThread = new AcceptThread();
            mAcceptThread.start();
        }
        setState(STATE_LISTEN);
    }

    //取消 CONNECTING 和 CONNECTED 状态下的相关线程，然后运行新的 mConnectThread 线程
    public synchronized void connect(BluetoothDevice device) {
        if (mState == STATE_CONNECTING) {
            if (mConnectThread != null) {
                mConnectThread.cancel();
                mConnectThread = null;
            }
        }
        if (mConnectedThread != null) {
            mConnectedThread.cancel();
            mConnectedThread = null;
        }
        mConnectThread = new ConnectThread(device);
        mConnectThread.start();
        setState(STATE_CONNECTING);
    }

    /*
        开启一个 ConnectedThread 来管理对应的当前连接。之前先取消任意现存的 mConnectThread 、
        mConnectedThread 、 mAcceptThread 线程，然后开启新 mConnectedThread ，传入当前刚刚接受的
        socket 连接。最后通过 Handler来通知UI连接
     */
    public synchronized void connected(BluetoothSocket socket, BluetoothDevice device) {
        if (mConnectThread != null) {
            mConnectThread.cancel();
            mConnectThread = null;
        }
        if (mConnectedThread != null) {
            mConnectedThread.cancel();
            mConnectedThread = null;
        }
        if (mAcceptThread != null) {
            mAcceptThread.cancel();
            mAcceptThread = null;
        }
        mConnectedThread = new ConnectedThread(socket);
        mConnectedThread.start();
        Message msg = mHandler.obtainMessage(weixinFragment.MESSAGE_DEVICE_NAME);
        Bundle bundle = new Bundle();
        bundle.putString(weixinFragment.DEVICE_NAME, device.getName());
        msg.setData(bundle);
        mHandler.sendMessage(msg);
        setState(STATE_CONNECTED);
    }

    // 停止所有相关线程，设当前状态为 NONE
    public synchronized void stop() {
        if (mConnectThread != null) {
            mConnectThread.cancel();
            mConnectThread = null;
        }
        if (mConnectedThread != null) {
            mConnectedThread.cancel();
            mConnectedThread = null;
        }
        if (mAcceptThread != null) {
            mAcceptThread.cancel();
            mAcceptThread = null;
        }
        setState(STATE_NONE);
    }

    // 在 STATE_CONNECTED 状态下，调用 mConnectedThread 里的 write 方法，写入 byte
    public void write(byte[] out) {
        ConnectedThread r;
        synchronized (this) {
            if (mState != STATE_CONNECTED)
                return;
            r = mConnectedThread;
        }
        r.write(out);
    }

    // 连接失败的时候处理，通知 ui ，并设为 STATE_LISTEN 状态
    public void connectionFailed() {
        setState(STATE_LISTEN);
        Message msg = mHandler.obtainMessage(weixinFragment.MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(weixinFragment.TOAST, "链接不到设备");
        msg.setData(bundle);
        mHandler.sendMessage(msg);
    }

    // 当连接失去的时候，设为 STATE_LISTEN 状态并通知 ui
    public void connectionLost() {
        setState(STATE_LISTEN);
        Message msg = mHandler.obtainMessage(weixinFragment.MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(weixinFragment.TOAST, "设备链接中断");
        msg.setData(bundle);
        mHandler.sendMessage(msg);
    }


    private class AcceptThread extends Thread {
        private final BluetoothServerSocket mmServerSocket;

        public AcceptThread() {
            BluetoothServerSocket tmp = null;
            try {
                //使用射频端口（RF comm）监听
                tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID);
            } catch (IOException e) {
            }
            mmServerSocket = tmp;
        }

        @Override
        public void run() {
            setName("AcceptThread");
            BluetoothSocket socket = null;
            while (mState != STATE_CONNECTED) {
                try {
                    socket = mmServerSocket.accept();
                } catch (IOException e) {
                    e.printStackTrace();
                    break;
                }
                if (socket != null) {
                    synchronized (ChatService.this) {
                        switch (mState) {
                            case STATE_LISTEN:
                            case STATE_CONNECTING:
                                connected(socket, socket.getRemoteDevice());
                                break;
                            case STATE_NONE:
                            case STATE_CONNECTED:
                                try {
                                    socket.close();
                                } catch (IOException e) {
                                    e.printStackTrace();
                                }
                                break;
                        }
                    }
                }
            }
        }


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

    /*
        连接线程，专门用来对外发出连接对方蓝牙的请求和处理流程。
        构造函数里通过 BluetoothDevice.createRfcommSocketToServiceRecord() ，
        从待连接的 device 产生 BluetoothSocket. 然后在 run 方法中 connect ，
        成功后调用 BluetoothChatSevice 的 connected() 方法。定义 cancel() 在关闭线程时能够关闭相关socket 。
     */
    private class ConnectThread extends Thread{
        private final BluetoothSocket mmSocket;
        private final BluetoothDevice mmDevice;

        public ConnectThread(BluetoothDevice device) {
            mmDevice = device;
            BluetoothSocket tmp = null;
            try {
                tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
            } catch (IOException e) {
                e.printStackTrace();
            }
            mmSocket = tmp;
        }

        @Override
        public void run() {
            setName("ConnectThread");
            mAdapter.cancelDiscovery();
            try {
                mmSocket.connect();
            } catch (IOException e) {
                connectionFailed();
                try {
                    mmSocket.close();
                } catch (IOException e2) {
                    e.printStackTrace();
                }
                ChatService.this.start();
                return;
            }
            synchronized (ChatService.this) {
                mConnectThread = null;
            }
            connected(mmSocket, mmDevice);
        }

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

    /*
        双方蓝牙连接后一直运行的线程；构造函数中设置输入输出流。
        run()方法中使用阻塞模式的 InputStream.read()循环读取输入流，然后发送到 UI 线程中更新聊天消息。
        本线程也提供了 write() 将聊天消息写入输出流传输至对方，传输成功后回写入 UI 线程。最后使用cancel()关闭连接的 socket
     */
    private class ConnectedThread extends Thread{
        private final BluetoothSocket mmSocket;
        private final InputStream mmInStream;
        private final OutputStream mmOutStream;

        public ConnectedThread(BluetoothSocket socket) {
            mmSocket = socket;
            InputStream tmpIn = null;
            OutputStream tmpOut = null;
            try {
                tmpIn = socket.getInputStream();
                tmpOut = socket.getOutputStream();
            } catch (IOException e) {
                e.printStackTrace();
            }
            mmInStream = tmpIn;
            mmOutStream = tmpOut;
        }

        @Override
        public void run() {
            byte[] buffer = new byte[1024];
            int bytes;
            while (true) {
                try {
                    bytes = mmInStream.read(buffer);
                    mHandler.obtainMessage(weixinFragment.MESSAGE_READ, bytes, -1, buffer).sendToTarget();
                } catch (IOException e) {
                    connectionLost();
                    break;
                }
            }
        }

        public void write(byte[] buffer) {
            try {
                mmOutStream.write(buffer);
                mHandler.obtainMessage(weixinFragment.MESSAGE_WRITE, -1, -1, buffer).sendToTarget();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

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

5.建立选择蓝牙设备的布局文件 device_list.xml

6.新建Activity组件DeviceList，实现选取与之会话的蓝牙设备

package com.e.bluetooth_chat;

import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.provider.Settings;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

import java.util.Set;

/*
        本程序供菜单项主界面的选项菜单“我的友好”调用，用于：
        （1）显示已配对的好友列表；
        （2）搜索可配对的好友进行配对
        （3）新选择并配对的蓝牙设备将刷新好友列表
        注意：发现新的蓝牙设备并请求配对时，需要对应接受
        关键技术：动态注册一个广播接收者，处理蓝牙设备扫描的结果
    */
public class DeviceList extends AppCompatActivity {
    private BluetoothAdapter mBtAdapter;
    private ArrayAdapter mPairedDevicesArrayAdapter;
    private ArrayAdapter mNewDevicesArrayAdapter;
    public static String EXTRA_DEVICE_ADDRESS = "device_address";  //Mac地址
    //定义广播接收者，用于处理扫描蓝牙设备后的结果
    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if(BluetoothDevice.ACTION_FOUND.equals(action)){
                BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                if(device.getBondState()!=BluetoothDevice.BOND_BONDED){
                    mNewDevicesArrayAdapter.add(device.getName()+"\n"+device.getAddress());
                }
            }else if(BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)){
                if(mNewDevicesArrayAdapter.getCount() == 0){
                    String noDevices = getResources().getText(R.string.none_found).toString();
                    mNewDevicesArrayAdapter.add(noDevices);
                }
            }
        }
    };

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.device_list);
        //在被调用活动里，设置返回结果码
        setResult(Activity.RESULT_CANCELED);
        init();  //活动界面
    }

    private void init() {
        Button scanButton = findViewById(R.id.button_scan);
        scanButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(DeviceList.this,R.string.scanning,Toast.LENGTH_LONG).show();
                doDiscovery();  //搜索蓝牙设备
            }
        });
        mPairedDevicesArrayAdapter = new ArrayAdapter(this,R.layout.device_name);
        mNewDevicesArrayAdapter = new ArrayAdapter(this, R.layout.device_name);
//        mPairedDevicesArrayAdapter = new ArrayAdapter(this,R.layout.device_name);
//        mNewDevicesArrayAdapter = new ArrayAdapter(this, R.layout.device_name);
        //已配对蓝牙设备列表
        ListView pairedListView =findViewById(R.id.paired_devices);
        pairedListView.setAdapter(mPairedDevicesArrayAdapter);
        pairedListView.setOnItemClickListener(mPaireDeviceClickListener);
        //未配对蓝牙设备列表
        ListView newDevicesListView = findViewById(R.id.new_devices);
        newDevicesListView.setAdapter(mNewDevicesArrayAdapter);
        newDevicesListView.setOnItemClickListener(mNewDeviceClickListener);
        //动态注册广播接收者
        IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
        registerReceiver(mReceiver, filter);
        filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
        registerReceiver(mReceiver, filter);
        mBtAdapter = BluetoothAdapter.getDefaultAdapter();
        Set pairedDevices = mBtAdapter.getBondedDevices();
        if (pairedDevices.size() > 0) {
            findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);
            for (BluetoothDevice device : pairedDevices) {
                mPairedDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
            }
        } else {
            String noDevices;
            noDevices = getResources().getText(R.string.none_paired).toString();
            mPairedDevicesArrayAdapter.add(noDevices);
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if(mBtAdapter!=null){
            mBtAdapter.cancelDiscovery();
        }
        this.unregisterReceiver(mReceiver);
    }

    private void doDiscovery() {
        findViewById(R.id.title_new_devices).setVisibility(View.VISIBLE);
        if (mBtAdapter.isDiscovering()) {
            mBtAdapter.cancelDiscovery();
        }
        mBtAdapter.startDiscovery();  //开始搜索蓝牙设备并产生广播
        //startDiscovery是一个异步方法
        //找到一个设备时就发送一个BluetoothDevice.ACTION_FOUND的广播
    }

    private AdapterView.OnItemClickListener mPaireDeviceClickListener = new AdapterView.OnItemClickListener() {
        public void onItemClick(AdapterView av, View v, int arg2, long arg3) {
            mBtAdapter.cancelDiscovery();
            String info = ((TextView) v).getText().toString();
            String address = info.substring(info.length() - 17);
            Intent intent = new Intent();
            intent.putExtra(EXTRA_DEVICE_ADDRESS, address);  //Mac地址
            setResult(Activity.RESULT_OK, intent);
            finish();
        }
    };

    private AdapterView.OnItemClickListener mNewDeviceClickListener = new AdapterView.OnItemClickListener() {
        public void onItemClick(AdapterView av, View v, int arg2, long arg3) {
            mBtAdapter.cancelDiscovery();
            Toast.makeText(DeviceList.this, "请在蓝牙设置界面手动连接设备",Toast.LENGTH_SHORT).show();
            Intent intent = new Intent(Settings.ACTION_BLUETOOTH_SETTINGS);
            startActivityForResult(intent,1);
        }
    };

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        init();
    }
}

7. 界面程序weixinFragment.java

package com.e.bluetooth_chat;

import android.Manifest;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;

import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.fragment.app.Fragment;

import android.os.Handler;
import android.os.Message;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.inputmethod.EditorInfo;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import androidx.appcompat.widget.Toolbar;


/**
 * A simple {@link Fragment} subclass.
 */
public class weixinFragment extends Fragment {

    //  蓝牙通信
    public static final int MESSAGE_STATE_CHANGE = 1;
    public static final int MESSAGE_READ = 2;
    public static final int MESSAGE_WRITE = 3;
    public static final int MESSAGE_DEVICE_NAME = 4;
    public static final int MESSAGE_TOAST = 5;
    public static final String DEVICE_NAME = "device_name";
    public static final String TOAST = "toast";
    private static final int REQUEST_CONNECT_DEVICE = 1;  //请求连接设备
    private static final int REQUEST_ENABLE_BT = 2;
    private TextView mTitle;
    private ListView mConversationView;
    private EditText mOutEditText;
    private Button mSendButton;
    private String mConnectedDeviceName = null;
    private ArrayAdapter mConversationArrayAdapter;
    private StringBuffer mOutStringBuffer;
    private BluetoothAdapter mBluetoothAdapter = null;
    private ChatService mChatService = null;

    View view;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.tab01, container, false);
        Toolbar toolbar = view.findViewById(R.id.toolbar);
        setHasOptionsMenu(true);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (ContextCompat.checkSelfPermission(view.getContext(), Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(getActivity(), new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, 1);
            }
        }
        //创建选项菜单
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            toolbar.inflateMenu(R.menu.option_menu);
        }
        //选项菜单监听
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            toolbar.setOnMenuItemClickListener(new MyMenuItemClickListener());
        }
        mTitle = view.findViewById(R.id.title_left_text);
        mTitle.setText("蓝牙通信");
        mTitle = view.findViewById(R.id.title_right_text);
        // 得到本地蓝牙适配器
        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        if (mBluetoothAdapter == null) {
            Toast.makeText(view.getContext(), "蓝牙不可用", Toast.LENGTH_LONG).show();
            getActivity().finish();
            return view;
        }
        if (!mBluetoothAdapter.isEnabled()) { //若当前设备蓝牙功能未开启
            Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableIntent, REQUEST_ENABLE_BT); //
        } else {
            if (mChatService == null) {
                setupChat();  //创建会话
            }
        }

        return view;
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if(grantResults.length>0){
            if(grantResults[0]!=PackageManager.PERMISSION_GRANTED){
                Toast.makeText(view.getContext(), "未授权，蓝牙搜索功能将不可用！", Toast.LENGTH_SHORT).show();
            }
        }
    }


    private void setupChat() {
        mConversationArrayAdapter = new ArrayAdapter(view.getContext(), R.layout.message);
        mConversationView = view.findViewById(R.id.in);
        mConversationView.setAdapter(mConversationArrayAdapter);
        mOutEditText = view.findViewById(R.id.edit_text_out);
        mOutEditText.setOnEditorActionListener(mWriteListener);
        mSendButton = view.findViewById(R.id.button_send);
        mSendButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                TextView textView = view.findViewById(R.id.edit_text_out);
                String message = textView.getText().toString();
                sendMessage(message);
            }
        });
        //创建服务对象
        mChatService = new ChatService(view.getContext(), mHandler);
        mOutStringBuffer = new StringBuffer("");
    }

    private void sendMessage(String message){
        if(mChatService.getState() != ChatService.STATE_CONNECTED){
            Toast.makeText(view.getContext(),R.string.not_connected,Toast.LENGTH_LONG).show();
            return;
        }
        if(message.length()>0){
            byte[] send = message.getBytes();
            mChatService.write(send);
            mOutStringBuffer.setLength(0);
            mOutEditText.setText(mOutStringBuffer);
        }
    }

    private void ensureDiscoverable() { 
        if (mBluetoothAdapter.getScanMode() != BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
            Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
            discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
            startActivity(discoverableIntent);
            Toast.makeText(view.getContext(), "已经设置本机蓝牙设备的可见性，对方可搜索了。", Toast.LENGTH_SHORT).show();
        }
    }

    private TextView.OnEditorActionListener mWriteListener = new TextView.OnEditorActionListener() {
        @Override
        public boolean onEditorAction(TextView view, int actionId, KeyEvent event) {
            if (actionId == EditorInfo.IME_NULL && event.getAction() == KeyEvent.ACTION_UP) {
                String message = view.getText().toString();
                sendMessage(message);
            }
            return true;
        }
    };

    private final Handler mHandler = new Handler() {   
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case MESSAGE_STATE_CHANGE:
                    switch (msg.arg1) {
                        case ChatService.STATE_CONNECTED:
                            mTitle.setText(R.string.title_connected_to);
                            mTitle.append(mConnectedDeviceName);
                            mConversationArrayAdapter.clear();
                            break;
                        case ChatService.STATE_CONNECTING:
                            mTitle.setText(R.string.title_connecting);
                            break;
                        case ChatService.STATE_LISTEN:
                        case ChatService.STATE_NONE:
                            mTitle.setText(R.string.title_not_connected);
                            break;
                    }
                    break;
                case MESSAGE_WRITE:
                    byte[] writeBuf = (byte[]) msg.obj;
                    String writeMessage = new String(writeBuf);
                    mConversationArrayAdapter.add("我:  " + writeMessage);
                    break;
                case MESSAGE_READ:
                    byte[] readBuf = (byte[]) msg.obj;
                    String readMessage = new String(readBuf, 0, msg.arg1);
                    mConversationArrayAdapter.add(mConnectedDeviceName + ":  "
                            + readMessage);
                    break;
                case MESSAGE_DEVICE_NAME:
                    mConnectedDeviceName = msg.getData().getString(DEVICE_NAME);
                    Toast.makeText(getActivity().getApplicationContext(),"链接到 " + mConnectedDeviceName, Toast.LENGTH_SHORT).show();
                    break;
                case MESSAGE_TOAST:
                    Toast.makeText(getActivity().getApplicationContext(), msg.getData().getString(TOAST), Toast.LENGTH_SHORT).show();
                    break;
            }
        }
    };

    //返回进入好友列表操作后的数回调方法
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
            case REQUEST_CONNECT_DEVICE:
                if (resultCode == Activity.RESULT_OK) {
                    String address = data.getExtras().getString(DeviceList.EXTRA_DEVICE_ADDRESS);
                    BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
                    mChatService.connect(device);
                }else if(resultCode==Activity.RESULT_CANCELED){
                    Toast.makeText(view.getContext(), "未选择任何好友！", Toast.LENGTH_SHORT).show();
                }
                break;
            case REQUEST_ENABLE_BT:
                if (resultCode == Activity.RESULT_OK) {
                    setupChat();
                } else {
                    Toast.makeText(view.getContext(), R.string.bt_not_enabled_leaving, Toast.LENGTH_SHORT).show();
                    getActivity().finish();
                }
        }
    }


    //内部类，选项菜单的单击事件处理
    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    private class MyMenuItemClickListener implements Toolbar.OnMenuItemClickListener {
        @Override
        public boolean onMenuItemClick(MenuItem item) {
            switch (item.getItemId()) {
                case R.id.scan:
                    //启动DeviceList这个Activity
                    Intent serverIntent = new Intent(getActivity(), DeviceList.class);
                    startActivityForResult(serverIntent, REQUEST_CONNECT_DEVICE);
                    return true;
                case R.id.discoverable:
                    ensureDiscoverable();
                    return true;
                case R.id.back:
                    getActivity().finish();
                    System.exit(0);
                    return true;
            }
            return false;
        }
    }


    @Override
    public synchronized void onResume() {
        //synchronized：同步方法实现排队调用
        super.onResume();
        if (mChatService != null) {
            if (mChatService.getState() == ChatService.STATE_NONE) {
                mChatService.start();
            }
        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        if(mChatService != null){
            mChatService.stop();
        }
    }
}

8.源码地址

https://github.com/xixia7/BlueTooth_Chat.git