安卓开发实现蓝牙通信——两设备相互发消息
功能说明：
- 实现设备之间通过蓝牙进行通信
- 两个设备之间互发消息
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。
效果显示
获取设备的定位信息和蓝牙权限，并设置我在线上：
查看已配对好友和其他可连接好友：
设备1：HUAWEI P30 PRO
设备2：MI 10 ULTRA
设备1和设备2的通信过程：
开发环境
- WIN10
- AS 2020.3.1
具体开发步骤
界面样式
共包含两个页面：蓝牙通信发送消息页面和寻找蓝牙好友设备。
通信界面activity_bluetooth_chat.xml
寻找设备界面activity_device_list.xml
注册权限
注册文件AndroidManifest.xml（注意这里ANDROID6.0以上就要加上定位权限才可以使用蓝牙）
所使用字符串
字符串strings.xml
Hello blank fragment
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
Java代码
蓝牙聊天Activity
本例演示了使用手机蓝牙实现会话功能
public class BluetoothChat extends AppCompatActivity{
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;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getSupportActionBar().hide(); //隐藏标题栏
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, 1);
}
}
Toolbar toolbar = findViewById(R.id.toolbar);
//创建选项菜单
toolbar.inflateMenu(R.menu.option_menu);
//选项菜单监听
toolbar.setOnMenuItemClickListener(new MyMenuItemClickListener());
mTitle = findViewById(R.id.title_left_text);
mTitle.setText(R.string.app_name);
mTitle = findViewById(R.id.title_right_text);
// 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
}
}
}
@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(this, "未授权，蓝牙搜索功能将不可用！", Toast.LENGTH_SHORT).show();
}
}
}
@Override
public synchronized void onResume() {
super.onResume();
if (mChatService != null) {
if (mChatService.getState() == ChatService.STATE_NONE) {
mChatService.start();
}
}
}
private void setupChat() {
mConversationArrayAdapter = new ArrayAdapter(this, R.layout.activity_main);
mConversationView = findViewById(R.id.in);
mConversationView.setAdapter(mConversationArrayAdapter);
mOutEditText = findViewById(R.id.edit_text_out);
mOutEditText.setOnEditorActionListener(mWriteListener);
mSendButton = findViewById(R.id.button_send);
mSendButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
TextView view = findViewById(R.id.edit_text_out);
String message = view.getText().toString();
sendMessage(message);
}
});
//创建服务对象
mChatService = new ChatService(this, mHandler);
mOutStringBuffer = new StringBuffer("");
}
@Override
public void onDestroy() {
super.onDestroy();
if (mChatService != null)
mChatService.stop();
}
private void ensureDiscoverable() { //修改本机蓝牙设备的可见性
//打开手机蓝牙后，能被其它蓝牙设备扫描到的时间不是永久的
if (mBluetoothAdapter.getScanMode() != BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
//设置在300秒内可见（能被扫描）
discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
startActivity(discoverableIntent);
Toast.makeText(this, "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 void sendMessage(String message) {
if (mChatService.getState() != ChatService.STATE_CONNECTED) {
Toast.makeText(this, R.string.not_connected, Toast.LENGTH_SHORT).show();
return;
}
if (message.length() > 0) {
byte[] send = message.getBytes();
mChatService.write(send);
mOutStringBuffer.setLength(0);
mOutEditText.setText(mOutStringBuffer);
}
}
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) {
//软键盘里的回车也能发送消息
String message = view.getText().toString();
sendMessage(message);
}
return true;
}
};
//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();
}
}
}
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(BluetoothChat.this, DeviceList.class);
startActivityForResult(serverIntent, REQUEST_CONNECT_DEVICE);
return true;
case R.id.discoverable:
ensureDiscoverable();
return true;
case R.id.back:
finish();
System.exit(0);
return true;
}
return false;
}
}
} 蓝牙工具类service：
ChatService是蓝牙会话的服务程序，定义了3个内部类：AcceptThread（接受新连接）、ConnectThread（发出连接）和ConnectedThread （已连接）。
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(BluetoothChat.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(BluetoothChat.MESSAGE_DEVICE_NAME);
Bundle bundle = new Bundle();
bundle.putString(BluetoothChat.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
private void connectionFailed() {
setState(STATE_LISTEN);
Message msg = mHandler.obtainMessage(BluetoothChat.MESSAGE_TOAST);
Bundle bundle = new Bundle();
bundle.putString(BluetoothChat.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
private void connectionLost() {
setState(STATE_LISTEN);
Message msg = mHandler.obtainMessage(BluetoothChat.MESSAGE_TOAST);
Bundle bundle = new Bundle();
bundle.putString(BluetoothChat.TOAST, "设备链接中断");
msg.setData(bundle);
mHandler.sendMessage(msg);
}
// 创建监听线程，准备接受新连接。使用阻塞方式，调用 BluetoothServerSocket.accept()
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();
}
}
}
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();
}
}
}
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();
}
}
}
}DeviceList供菜单项主界面的选项菜单“我的好友”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，关键是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 {
public static final String TAG="device";
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(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() {
Log.d(TAG,"跳转搜索蓝牙页面");
Button scanButton = findViewById(R.id.button_scan);
scanButton.setOnClickListener(new View.OnClickListener() {
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_list);
mNewDevicesArrayAdapter = new ArrayAdapter(this, R.layout.device_list);
//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 = 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);
}
};
//回调方法：进入蓝牙配对设置界面返回后执行
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
init(); //刷新好友列表
}
} 代码参考
sy09（Android近距离通信）