android studio实现蓝牙通信

添加蓝牙权限

 
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.BLUETOOTH" />

在文件res/values/strings.xml里，添加程序运行过程中的状态描述文本

<resources>
    <string name="app_name">蓝牙Demostring>
    <string name="send">发送string>
    <string name="not_connected">你没有链接一个设备string>
    <string name="bt_not_enabled_leaving">蓝牙不可用，离开聊天室string>
    <string name="title_connecting">链接中...string>
    <string name="title_connected_to">连接到：string>
    <string name="title_not_connected">无链接string>
    <string name="scanning">蓝牙设备搜索中...string>
    <string name="select_device">选择一个好友链接string>
    <string name="none_paired">没有配对好友string>
    <string name="none_found">附近没有发现好友string>
    <string name="title_paired_devices">已配对好友string>
    <string name="title_other_devices">其它可连接好友string>
    <string name="button_scan">搜索好友string>
    <string name="connect">我的好友string>
    <string name="discoverable">设置在线string>
    <string name="back">退出string>
    <string name="startVideo">开始聊天string>
    <string name="stopVideo">结束聊天string>
resources>

编写布局文件添加一个

使用垂直线性布局并嵌套水平线性布局实现，添加，添加1个Toolbar控件，其内包含2个水平的TextView控件；在Toolbar控件的下方添加1个ListView控件，用于显示聊天内容；最后在ListView控件的下方添加水平放置的1个EditText控件和一个Button控件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    
    <androidx.appcompat.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <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:gravity="left"
                android:ellipsize="end"
                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>

    <ListView android:id="@+id/in"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:stackFromBottom="true"
        android:transcriptMode="alwaysScroll"
        android:layout_weight="1" />
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
        <EditText android:id="@+id/edit_text_out"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:layout_gravity="bottom" />
        <Button android:id="@+id/button_send"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/send"/>
    LinearLayout>
LinearLayout>

编写用于蓝牙会话的服务组件ChatService

定义了3个内部类：AcceptThread（接受新连接）、ConnectThread（发出连接）和ConnectedThread （已连接）

AcceptThread

 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) {
                    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();
            }
        }
    }

ConnectThread

    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();
            }
        }
    }

ConnectedThread

    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(BluetoothChat.MESSAGE_READ, bytes, -1, buffer).sendToTarget();
                } catch (IOException e) {
                    connectionLost();
                    break;
                }
            }
        }

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

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

建立供BluetoothChat使用的菜单文件optionmenu.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@+id/scan"
        android:icon="@android:drawable/ic_menu_myplaces"
        android:title="@string/connect" />
    <item android:id="@+id/discoverable"
        android:icon="@android:drawable/ic_menu_view"
        android:title="@string/discoverable" />
    <item android:id="@+id/back"
        android:icon="@android:drawable/ic_menu_close_clear_cancel"
        android:title="@string/back" />
menu>

新建组件DeviceList，实现选取与之会话的蓝牙设备

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
定义已配对和未配对的蓝牙设备列表

        //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);

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

        //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<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 = getResources().getText(R.string.none_paired).toString();
            mPairedDevicesArrayAdapter.add(noDevices);
        }

其中两个监听事件mPaireDeviceClickListener，mNewDeviceClickListener为

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);
        }
    };

使用菜单File→Refactor→Rename，重命名模块的MainActivity为BluetoothChat

实验步骤：
（1）在两个手机分别安装、运行本应用。如果未打开手机蓝牙，则进入打开蓝牙设置界面；
（2）在OptionMenu（选项菜单）里，选择“我的好友”，即可直接连接，再进行会话；
（3）新建好友前，需要先使用选项菜单“设置在线”，即要求对方可见（能被扫描到）。
然后，单击“搜索好友”按钮。

得到本地蓝牙适配器

  mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        if (mBluetoothAdapter == null) {
            Toast.makeText(this, "蓝牙不可用", Toast.LENGTH_LONG).show();
            finish();
            return;
        }
        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
            }
        }

使用Handler对象在UI主线程与子线程之间传递消息

private final Handler mHandler = new Handler() {   //消息处理
        @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(getApplicationContext(),"链接到 " + mConnectedDeviceName, Toast.LENGTH_SHORT).show();
                    break;
                case MESSAGE_TOAST:
                    Toast.makeText(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) {
        super.onActivityResult( requestCode, resultCode, 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( this, "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( this, R.string.bt_not_enabled_leaving, Toast.LENGTH_SHORT ).show();
                    finish();
                }
        }
    }

附加device_name和message两个xml文件

两个文件只需要添加一个TextView组件即可

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textSize="18sp"
    android:padding="5dp"
    />

实验代码

BlueToothChat.