Android Studio 入門：（七） 安卓藍牙聊天功能的實現

目錄

1. 清單文件註冊權限

2. 在文件res/values/strings.xml裏，添加程序運行過程中的狀態描述文本及配色代碼等

3.修改聊天界面佈局文件

4.用於藍牙會話的服務組件ChatService

5.建立選擇藍牙設備的佈局文件 device_list.xml

6.新建Activity組件DeviceList，實現選取與之會話的藍牙設備

7. 界面程序weixinFragment.java

8.源碼地址

---

1. 清單文件註冊權限

<!--下面2個是普通權限，只需要在清單文件裏註冊，不需要在程序裏動態申請-->
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />

<!--搜索WiFi，需要定位權限，它是危險權限，在此聲明外，還需要在程序裏動態申請-->
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

2. 在文件res/values/strings.xml裏，添加程序運行過程中的狀態描述文本及配色代碼等

<resources>
    <string name="app_name">BlueTooth_Chat</string>
    <string name="top_name">藍牙聊天</string>
    <string name="bottom_image">底部圖標</string>
    <string name="bottom_name1">微信</string>
    <string name="bottom_name2">朋友</string>
    <string name="bottom_name3">通訊錄</string>
    <string name="bottom_name4">設置</string>

    <string name="send">發送</string>
    <string name="not_connected">你沒有鏈接一個設備</string>
    <string name="bt_not_enabled_leaving">藍牙不可用，離開聊天室</string>
    <string name="title_connecting">鏈接中...</string>
    <string name="title_connected_to">連接到：</string>
    <string name="title_not_connected">無鏈接</string>
    <string name="scanning">藍牙設備搜索中...</string>
    <string name="select_device">選擇一個好友鏈接</string>
    <string name="none_paired">沒有配對好友</string>
    <string name="none_found">附近沒有發現好友</string>
    <string name="title_paired_devices">已配對好友</string>
    <string name="title_other_devices">其它可連接好友</string>
    <string name="button_scan">搜索好友</string>
    <string name="connect">我的好友</string>
    <string name="discoverable">設置在線</string>
    <string name="back">退出</string>
    <string name="startVideo">開始聊天</string>
    <string name="stopVideo">結束聊天</string>

    <!-- TODO: Remove or change this placeholder text -->
    <string name="hello_blank_fragment">Hello blank fragment</string>
</resources>

3.修改聊天界面佈局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/device_name"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/bg01"
    android:orientation="vertical">

    <!--新版Android支持的Toolbar，對標題欄佈局-->
    <!--    <android.support.v7.widget.Toolbar-->
    <androidx.appcompat.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="34dp">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/title_left_text"
                style="?android:attr/windowTitleStyle"
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_alignParentLeft="true"
                android:layout_weight="1"
                android:ellipsize="end"
                android:gravity="left"
                android:singleLine="true" />

            <TextView
                android:id="@+id/title_right_text"
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_alignParentRight="true"
                android:layout_weight="1"
                android:ellipsize="end"
                android:gravity="right"
                android:singleLine="true"
                android:textColor="#fff" />
        </LinearLayout>
    </androidx.appcompat.widget.Toolbar>
    <!--    </android.support.v7.widget.Toolbar>-->

    <ListView
        android:id="@+id/in"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:stackFromBottom="true"
        android:transcriptMode="alwaysScroll" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <EditText
            android:id="@+id/edit_text_out"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom"
            android:layout_weight="1" />

        <Button
            android:id="@+id/button_send"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/send" />
    </LinearLayout>
</LinearLayout>

4.用於藍牙會話的服務組件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 {
    //本應用的主Activity組件名稱
    private static final String NAME = "BlueToothChat";
    // UUID：通用唯一識別碼,是一個128位長的數字，一般用十六進制表示
    //算法的核心思想是結合機器的網卡、當地時間、一個隨機數來生成
    //在創建藍牙連接
    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;

    //構造方法，接收UI主線程傳遞的對象
    public ChatService(Context context,Handler handler){
        //構造方法完成藍牙對象的創建
        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 狀態下的相關線程，然後運行新的 mConnectThread 線程
    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);
    }

    /*
        開啓一個 ConnectedThread 來管理對應的當前連接。之前先取消任意現存的 mConnectThread 、
        mConnectedThread 、 mAcceptThread 線程，然後開啓新 mConnectedThread ，傳入當前剛剛接受的
        socket 連接。最後通過 Handler來通知UI連接
     */
    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);
    }

    // 停止所有相關線程，設當前狀態爲 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 狀態下，調用 mConnectedThread 裏的 write 方法，寫入 byte
    public void write(byte[] out) {
        ConnectedThread r;
        synchronized (this) {
            if (mState != STATE_CONNECTED)
                return;
            r = mConnectedThread;
        }
        r.write(out);
    }

    // 連接失敗的時候處理，通知 ui ，並設爲 STATE_LISTEN 狀態
    public void connectionFailed() {
        setState(STATE_LISTEN);
        Message msg = mHandler.obtainMessage(weixinFragment.MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(weixinFragment.TOAST, "鏈接不到設備");
        msg.setData(bundle);
        mHandler.sendMessage(msg);
    }

    // 當連接失去的時候，設爲 STATE_LISTEN 狀態並通知 ui
    public void connectionLost() {
        setState(STATE_LISTEN);
        Message msg = mHandler.obtainMessage(weixinFragment.MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(weixinFragment.TOAST, "設備鏈接中斷");
        msg.setData(bundle);
        mHandler.sendMessage(msg);
    }


    private class AcceptThread extends Thread {
        private final BluetoothServerSocket mmServerSocket;

        public AcceptThread() {
            BluetoothServerSocket tmp = null;
            try {
                //使用射頻端口（RF comm）監聽
                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();
            }
        }
    }

    /*
        連接線程，專門用來對外發出連接對方藍牙的請求和處理流程。
        構造函數裏通過 BluetoothDevice.createRfcommSocketToServiceRecord() ，
        從待連接的 device 產生 BluetoothSocket. 然後在 run 方法中 connect ，
        成功後調用 BluetoothChatSevice 的 connected() 方法。定義 cancel() 在關閉線程時能夠關閉相關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();
            }
        }
    }

    /*
        雙方藍牙連接後一直運行的線程；構造函數中設置輸入輸出流。
        run()方法中使用阻塞模式的 InputStream.read()循環讀取輸入流，然後發送到 UI 線程中更新聊天消息。
        本線程也提供了 write() 將聊天消息寫入輸出流傳輸至對方，傳輸成功後回寫入 UI 線程。最後使用cancel()關閉連接的 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.建立選擇藍牙設備的佈局文件 device_list.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView android:id="@+id/title_paired_devices"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/title_paired_devices"
        android:visibility="gone"
        android:background="#666"
        android:textColor="#fff"
        android:paddingLeft="5dp"
        android:paddingStart="5dp" />
    <ListView android:id="@+id/paired_devices"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1" />
    <TextView android:id="@+id/title_new_devices"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/title_other_devices"
        android:visibility="gone"
        android:background="#666"
        android:textColor="#fff"
        android:paddingLeft="5dp"
        android:paddingStart="5dp" />
    <!--android:visibility="gone"表示不佔空間的隱藏，invisible是佔空間-->
    <ListView android:id="@+id/new_devices"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="2" />
    <Button android:id="@+id/button_scan"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/button_scan" />
</LinearLayout>

6.新建Activity組件DeviceList，實現選取與之會話的藍牙設備

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;

/*
        本程序供菜單項主界面的選項菜單“我的友好”調用，用於：
        （1）顯示已配對的好友列表；
        （2）搜索可配對的好友進行配對
        （3）新選擇並配對的藍牙設備將刷新好友列表
        注意：發現新的藍牙設備並請求配對時，需要對應接受
        關鍵技術：動態註冊一個廣播接收者，處理藍牙設備掃描的結果
    */
public class DeviceList extends AppCompatActivity {
    private BluetoothAdapter mBtAdapter;
    private ArrayAdapter<String> mPairedDevicesArrayAdapter;
    private ArrayAdapter<String> mNewDevicesArrayAdapter;
    public static String EXTRA_DEVICE_ADDRESS = "device_address";  //Mac地址
    //定義廣播接收者，用於處理掃描藍牙設備後的結果
    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);
        //在被調用活動裏，設置返回結果碼
        setResult(Activity.RESULT_CANCELED);
        init();  //活動界面
    }

    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();  //搜索藍牙設備
            }
        });
        mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this,R.layout.device_name);
        mNewDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name);
//        mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this,R.layout.device_name);
//        mNewDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name);
        //已配對藍牙設備列表
        ListView pairedListView =findViewById(R.id.paired_devices);
        pairedListView.setAdapter(mPairedDevicesArrayAdapter);
        pairedListView.setOnItemClickListener(mPaireDeviceClickListener);
        //未配對藍牙設備列表
        ListView newDevicesListView = findViewById(R.id.new_devices);
        newDevicesListView.setAdapter(mNewDevicesArrayAdapter);
        newDevicesListView.setOnItemClickListener(mNewDeviceClickListener);
        //動態註冊廣播接收者
        IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
        registerReceiver(mReceiver, filter);
        filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
        registerReceiver(mReceiver, filter);
        mBtAdapter = BluetoothAdapter.getDefaultAdapter();
        Set<BluetoothDevice> 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();  //開始搜索藍牙設備併產生廣播
        //startDiscovery是一個異步方法
        //找到一個設備時就發送一個BluetoothDevice.ACTION_FOUND的廣播
    }

    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, "請在藍牙設置界面手動連接設備",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 {

    //  藍牙通信
    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;  //請求連接設備
    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<String> 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);
            }
        }
        //創建選項菜單
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            toolbar.inflateMenu(R.menu.option_menu);
        }
        //選項菜單監聽
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            toolbar.setOnMenuItemClickListener(new MyMenuItemClickListener());
        }
        mTitle = view.findViewById(R.id.title_left_text);
        mTitle.setText("藍牙通信");
        mTitle = view.findViewById(R.id.title_right_text);
        // 得到本地藍牙適配器
        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        if (mBluetoothAdapter == null) {
            Toast.makeText(view.getContext(), "藍牙不可用", Toast.LENGTH_LONG).show();
            getActivity().finish();
            return view;
        }
        if (!mBluetoothAdapter.isEnabled()) { //若當前設備藍牙功能未開啓
            Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableIntent, REQUEST_ENABLE_BT); //
        } else {
            if (mChatService == null) {
                setupChat();  //創建會話
            }
        }

        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(), "未授權，藍牙搜索功能將不可用！", Toast.LENGTH_SHORT).show();
            }
        }
    }


    private void setupChat() {
        mConversationArrayAdapter = new ArrayAdapter<String>(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);
            }
        });
        //創建服務對象
        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(), "已經設置本機藍牙設備的可見性，對方可搜索了。", 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(),"鏈接到 " + mConnectedDeviceName, Toast.LENGTH_SHORT).show();
                    break;
                case MESSAGE_TOAST:
                    Toast.makeText(getActivity().getApplicationContext(), msg.getData().getString(TOAST), Toast.LENGTH_SHORT).show();
                    break;
            }
        }
    };

    //返回進入好友列表操作後的數回調方法
    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(), "未選擇任何好友！", 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();
                }
        }
    }


    //內部類，選項菜單的單擊事件處理
    @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:
                    //啓動DeviceList這個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：同步方法實現排隊調用
        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.源碼地址

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