蓝牙开发的大致流程：
1、蓝牙权限
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.BLUETOOTH" />
2、认设备是否支持蓝牙
/**
* 确认设备是否支持蓝牙
* 如果getDefaultAdapter()返回null,则这个设备不支持蓝牙
*/
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
// If the adapter is null, then Bluetooth is not supported
//手机不支持蓝牙
if (mBluetoothAdapter == null) {
Toast.makeText(this, "Bluetooth is not available", Toast.LENGTH_LONG).show();
finish();
return;
}
3、确定蓝牙能够使用
/**
* 确定蓝牙能够使用。
* 通过isEnabled()来检查蓝牙当前是否可用。
* 如果这个方法返回false,则蓝牙不能够使用。这个时候 就请求蓝牙使用，通过intent来请求
* 在onActivityResult（）里面判断
*/
if (!mBluetoothAdapter.isEnabled()) {
Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
// Otherwise, setup the chat session
}
会打开一个对话框中显示请求使用蓝牙权限。如果响应"Yes",这个进程完成（或失败）后你的应用将能够使用蓝牙，选择no，就结束应用
case REQUEST_ENABLE_BT:
// When the request to enable Bluetooth returns
if (resultCode == Activity.RESULT_OK) {
// Bluetooth is now enabled, so set up a chat session
//请求蓝牙成功，这个时候 蓝也可用
setupChat();
} else {
// User did not enable Bluetooth or an error occurred
//请求蓝牙失败，退出应用
Log.d(TAG, "BT not enabled");
Toast.makeText(this, R.string.bt_not_enabled_leaving, Toast.LENGTH_SHORT).show();
finish();
}
4、最为服务器端，你必须让其他设备能够看到你，才能跟你建立连接
//设置自己可以被其他设备搜索到
private void ensureDiscoverable() {
if(D) Log.d(TAG, "ensure discoverable");
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);
}
}
5、找已经匹配的设备
在搜索设备前，查询配对设备看需要的设备是否已经是已经存在是很值得的，可以调用getBondedDevices()来做到，该函数会返回一个描述配对设备BluetoothDevice的结果集
//查找已经匹配的设备
Set<BluetoothDevice> pairedDevices = mBtAdapter.getBondedDevices();
// If there are paired devices, add each one to the ArrayAdapter
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);
}
6、扫描设备
/**
* Start device discover with the BluetoothAdapter
*/
private void doDiscovery() {
if (D) Log.d(TAG, "doDiscovery()");
// Indicate scanning in the title
setProgressBarIndeterminateVisibility(true);
setTitle(R.string.scanning);
// Turn on sub-title for new devices
findViewById(R.id.title_new_devices).setVisibility(View.VISIBLE);
// If we're already discovering, stop it
//如果正在搜索 就先停止
if (mBtAdapter.isDiscovering()) {
mBtAdapter.cancelDiscovery();
}
// Request discover from BluetoothAdapter
//搜索设备 用BroadcastReceiver接受BluetoothDevice.ACTION_FOUND
mBtAdapter.startDiscovery();
}
要开始搜索设备，只需简单的调用startDiscovery() 。该函数时异步的，调用后立即返回，返回值表示搜索是否成功开始。可以再BroadcastReceiver里面监听结果
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
// When discovery finds a device
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
// Get the BluetoothDevice object from the Intent
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
// If it's already paired, skip it, because it's been listed already
if (device.getBondState() != BluetoothDevice.BOND_BONDED) {
mNewDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
}
// When discovery is finished, change the Activity title
}
};
7、作为客户端连接
扫描出来的列表，单击任意一个item，得到这个设备的mac地址和name
// The on-click listener for all devices in the ListViews
private OnItemClickListener mDeviceClickListener = new OnItemClickListener() {
public void onItemClick(AdapterView<?> av, View v, int arg2, long arg3) {
// Cancel discovery because it's costly and we're about to connect
//停止搜索
mBtAdapter.cancelDiscovery();
// Get the device MAC address, which is the last 17 chars in the View
String info = ((TextView) v).getText().toString();
String address = info.substring(info.length() - 17);
// Create the result Intent and include the MAC address
Intent intent = new Intent();
intent.putExtra(EXTRA_DEVICE_ADDRESS, address);
// Set result and finish this Activity
setResult(Activity.RESULT_OK, intent);
finish();
}
};
根据mac地址 得到远端BluetoothDevice
BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
然后 根据device得到BluetoothSocket,并建立连接
private class ConnectThread extends Thread {
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
private String mSocketType;
public ConnectThread(BluetoothDevice device, boolean secure) {
mmDevice = device;
BluetoothSocket tmp = null;
mSocketType = secure ? "Secure" : "Insecure";
// Get a BluetoothSocket for a connection with the
// given BluetoothDevice
//来生成一个BluetoothSocket对象
//这个uuid必须服务器和客户端是同一个
try {
if (secure) {
tmp = device.createRfcommSocketToServiceRecord(
MY_UUID_SECURE);
} else {
tmp = device.createInsecureRfcommSocketToServiceRecord(
MY_UUID_INSECURE);
}
} catch (IOException e) {
Log.e(TAG, "Socket Type: " + mSocketType + "create() failed", e);
}
mmSocket = tmp;
}
public void run() {
Log.i(TAG, "BEGIN mConnectThread SocketType:" + mSocketType);
//设置当前线程名字
setName("ConnectThread" + mSocketType);
// Always cancel discovery because it will slow down a connection
//因为扫描设备 很浪费资源 停止扫描
mAdapter.cancelDiscovery();
// Make a connection to the BluetoothSocket
//用connect()完成连接
//系统会在远程设备上完成一个SDP查找来匹配UUID。
//如果查找成功并且远程设备接受连接，就共享RFCOMM信道，connect()会返回。
//这也是一个阻塞的调用，不管连接失败还是超时（12秒）都会抛出异常。
try {
// This is a blocking call and will only return on a
// successful connection or an exception
mmSocket.connect();
} catch (IOException e) {
// Close the socket
try {
mmSocket.close();
} catch (IOException e2) {
Log.e(TAG, "unable to close() " + mSocketType +
" socket during connection failure", e2);
}
connectionFailed();
return;
}
// Reset the ConnectThread because we're done
synchronized (BluetoothChatService.this) {
mConnectThread = null;
}
// Start the connected thread
//启动连接成功 可以通信的线程
connected(mmSocket, mmDevice, mSocketType);
}
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) {
Log.e(TAG, "close() of connect " + mSocketType + " socket failed", e);
}
}
}
8、作为服务器端建立连接
private class AcceptThread extends Thread {
// The local server socket
private final BluetoothServerSocket mmServerSocket;
private String mSocketType;
public AcceptThread(boolean secure) {
BluetoothServerSocket tmp = null;
mSocketType = secure ? "Secure":"Insecure";
// Create a new listening server socket
//通过调用listenUsingRfcommWithServiceRecord(String, UUID)得到一个BluetoothServerSocket对象
try {
if (secure) {
tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME_SECURE,
MY_UUID_SECURE);
} else {
tmp = mAdapter.listenUsingInsecureRfcommWithServiceRecord(
NAME_INSECURE, MY_UUID_INSECURE);
}
} catch (IOException e) {
Log.e(TAG, "Socket Type: " + mSocketType + "listen() failed", e);
}
mmServerSocket = tmp;
}
public void run() {
if (D) Log.d(TAG, "Socket Type: " + mSocketType +
"BEGIN mAcceptThread" + this);
setName("AcceptThread" + mSocketType);
BluetoothSocket socket = null;
// Listen to the server socket if we're not connected
while (mState != STATE_CONNECTED) {
try {
// This is a blocking call and will only return on a
// successful connection or an exception
//通过调用accept()来侦听连接请求。
socket = mmServerSocket.accept();
} catch (IOException e) {
Log.e(TAG, "Socket Type: " + mSocketType + "accept() failed", e);
break;
}
// If a connection was accepted
if (socket != null) {
synchronized (BluetoothChatService.this) {
switch (mState) {
case STATE_LISTEN:
case STATE_CONNECTING:
// Situation normal. Start the connected thread.
connected(socket, socket.getRemoteDevice(),
mSocketType);
break;
case STATE_NONE:
case STATE_CONNECTED:
// Either not ready or already connected. Terminate new socket.
try {
socket.close();
} catch (IOException e) {
Log.e(TAG, "Could not close unwanted socket", e);
}
break;
}
}
}
}
if (D) Log.i(TAG, "END mAcceptThread, socket Type: " + mSocketType);
}
public void cancel() {
if (D) Log.d(TAG, "Socket Type" + mSocketType + "cancel " + this);
try {
mmServerSocket.close();
} catch (IOException e) {
Log.e(TAG, "Socket Type" + mSocketType + "close() of server failed", e);
}
}
}
9、与远端设备通信
//处理与远端的通信
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket socket, String socketType) {
Log.d(TAG, "create ConnectedThread: " + socketType);
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the BluetoothSocket input and output streams
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) {
Log.e(TAG, "temp sockets not created", e);
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
Log.i(TAG, "BEGIN mConnectedThread");
byte[] buffer = new byte[1024];
int bytes;
// Keep listening to the InputStream while connected
while (true) {
try {
// Read from the InputStream
bytes = mmInStream.read(buffer);
// Send the obtained bytes to the UI Activity
mHandler.obtainMessage(BluetoothChat.MESSAGE_READ, bytes, -1, buffer)
.sendToTarget();
} catch (IOException e) {
Log.e(TAG, "disconnected", e);
connectionLost();
// Start the service over to restart listening mode
BluetoothChatService.this.start();
break;
}
}
}
/**
* Write to the connected OutStream.
* @param buffer The bytes to write
*/
//发送信息给远端
public void write(byte[] buffer) {
try {
mmOutStream.write(buffer);
// Share the sent message back to the UI Activity
mHandler.obtainMessage(BluetoothChat.MESSAGE_WRITE, -1, -1, buffer)
.sendToTarget();
} catch (IOException e) {
Log.e(TAG, "Exception during write", e);
}
}
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) {
Log.e(TAG, "close() of connect socket failed", e);
}
}
}
附件是官网的例子，稍微加了点注释