什么是蓝牙
Android 平台包含蓝牙网络堆栈支持，此支持能让设备以无线方式与其他蓝牙设备交换数据。应用框架提供通过 Android Bluetooth API 访问蓝牙功能的权限。这些 API 允许应用以无线方式连接到其他蓝牙设备，从而实现点到点和多点无线功能。
Android 应用可通过 Bluetooth API 执行以下操作：
扫描其他蓝牙设备
查询本地蓝牙适配器的配对蓝牙设备
建立 RFCOMM 通道
通过服务发现连接到其他设备
与其他设备进行双向数据传输
管理多个连接
蓝牙权限
如要在应用中使用蓝牙功能，您必须声明两个权限。第一个是 BLUETOOTH。您需要此权限才能执行任何蓝牙通信，例如请求连接、接受连接和传输数据等。
第二个必须声明的权限是 ACCESS_FINE_LOCATION。您的应用需要此权限，因为蓝牙扫描可用于收集用户的位置信息。此类信息可能来自用户自己的设备，以及在商店和交通设施等位置使用的蓝牙信标。
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
设置蓝牙
1.获取
BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (bluetoothAdapter == null) {
// Device doesn't support Bluetooth
}
2.启用
if (!bluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
查找设备
1.查询已配对的设备
Set<BluetoothDevice> pairedDevices = bluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
// There are paired devices. Get the name and address of each paired device.
for (BluetoothDevice device : pairedDevices) {
String deviceName = device.getName();
String deviceHardwareAddress = device.getAddress(); // MAC address
}
}
2.发现设备
@Override
protected void onCreate(Bundle savedInstanceState) {
...
// Register for broadcasts when a device is discovered.
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(receiver, filter);
}
// Create a BroadcastReceiver for ACTION_FOUND.
private final BroadcastReceiver receiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
// Discovery has found a device. Get the BluetoothDevice
// object and its info from the Intent.
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
String deviceName = device.getName();
String deviceHardwareAddress = device.getAddress(); // MAC address
}
}
};
@Override
protected void onDestroy() {
super.onDestroy();
...
// Don't forget to unregister the ACTION_FOUND receiver.
unregisterReceiver(receiver);
}
连接设备
private class AcceptThread extends Thread {
private final BluetoothServerSocket mmServerSocket;
public AcceptThread() {
// Use a temporary object that is later assigned to mmServerSocket
// because mmServerSocket is final.
BluetoothServerSocket tmp = null;
try {
// MY_UUID is the app's UUID string, also used by the client code.
tmp = bluetoothAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID);
} catch (IOException e) {
Log.e(TAG, "Socket's listen() method failed", e);
}
mmServerSocket = tmp;
}
public void run() {
BluetoothSocket socket = null;
// Keep listening until exception occurs or a socket is returned.
while (true) {
try {
socket = mmServerSocket.accept();
} catch (IOException e) {
Log.e(TAG, "Socket's accept() method failed", e);
break;
}
if (socket != null) {
// A connection was accepted. Perform work associated with
// the connection in a separate thread.
manageMyConnectedSocket(socket);
mmServerSocket.close();
break;
}
}
}
// Closes the connect socket and causes the thread to finish.
public void cancel() {
try {
mmServerSocket.close();
} catch (IOException e) {
Log.e(TAG, "Could not close the connect socket", e);
}
}
}
服务端代码
class AcceptThread extends Thread {
private BluetoothServerSocket mServerSocket;
private BluetoothSocket mSocket;
private InputStream btIs;
private OutputStream btOs;
private PrintWriter writer;
private boolean canAccept;
private boolean canRecv;
public AcceptThread() {
canAccept = true;
canRecv = true;
}
@Override
public void run() {
try {
//获取套接字
BluetoothServerSocket temp = mBluetoothAdapter.listenUsingInsecureRfcommWithServiceRecord("TEST", UUID.fromString(BT_UUID));
mServerSocket = temp;
//监听连接请求 -- 作为测试，只允许连接一个设备
if (mServerSocket != null) {
// while (canAccept) {
mSocket = mServerSocket.accept();//阻塞等待客户端连接
sendHandlerMsg("有客户端连接");
// }
}
//获取输入输出流
btIs = mSocket.getInputStream();
btOs = mSocket.getOutputStream();
//通讯-接收消息
BufferedReader reader = new BufferedReader(new InputStreamReader(btIs, "UTF-8"));
String content = null;
while (canRecv) {
content = reader.readLine();
sendHandlerMsg("收到消息：" + content);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (mSocket != null) {
mSocket.close();
}
// btIs.close();//两个输出流都依赖socket，关闭socket即可
// btOs.close();
} catch (IOException e) {
e.printStackTrace();
sendHandlerMsg("错误：" + e.getMessage());
}
}
}
private void sendHandlerMsg(String content) {
Message msg = mHandler.obtainMessage();
msg.what = 1001;
msg.obj = content;
mHandler.sendMessage(msg);
}
public void write(String msg) {
if (btOs != null) {
try {
if (writer == null) {
writer = new PrintWriter(new OutputStreamWriter(btOs, "UTF-8"), true);
}
writer.println(msg);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
writer.close();
sendHandlerMsg("错误：" + e.getMessage());
}
}
}
}
客户端代码
private class ConnectThread extends Thread {
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
public ConnectThread(BluetoothDevice device) {
// Use a temporary object that is later assigned to mmSocket
// because mmSocket is final.
BluetoothSocket tmp = null;
mmDevice = device;
try {
// Get a BluetoothSocket to connect with the given BluetoothDevice.
// MY_UUID is the app's UUID string, also used in the server code.
tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {
Log.e(TAG, "Socket's create() method failed", e);
}
mmSocket = tmp;
}
public void run() {
// Cancel discovery because it otherwise slows down the connection.
bluetoothAdapter.cancelDiscovery();
try {
// Connect to the remote device through the socket. This call blocks
// until it succeeds or throws an exception.
mmSocket.connect();
} catch (IOException connectException) {
// Unable to connect; close the socket and return.
try {
mmSocket.close();
} catch (IOException closeException) {
Log.e(TAG, "Could not close the client socket", closeException);
}
return;
}
// The connection attempt succeeded. Perform work associated with
// the connection in a separate thread.
manageMyConnectedSocket(mmSocket);
}
// Closes the client socket and causes the thread to finish.
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) {
Log.e(TAG, "Could not close the client socket", e);
}
}
}