蓝牙是一种支持设备短距离传输数据的无线技术。android在2.0以后提供了这方面的支持。
从查找蓝牙设备到能够相互通信要经过几个基本步骤(本机做为服务器)：
1.设置权限
在manifest中配置
Xml代码
1. <uses-permissionandroid:name="android.permission.BLUETOOTH"/>
2. <uses-permissionandroid:name="android.permission.BLUETOOTH_ADMIN"/>
<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
2.启动蓝牙
首先要查看本机是否支持蓝牙，获取BluetoothAdapter蓝牙适配器对象
Java代码
1. BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
2. if(mBluetoothAdapter == null){
3. //表明此手机不支持蓝牙
4. return;
5. }
6. if(!mBluetoothAdapter.isEnabled()){ //蓝牙未开启，则开启蓝牙
7. new
8. startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
9. }
10. //......
11. public void onActivityResult(int requestCode,int
12. if(requestCode == REQUEST_ENABLE_BT){
13. if(requestCode == RESULT_OK){
14. //蓝牙已经开启
15. }
16. }
17. }
BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if(mBluetoothAdapter == null){
//表明此手机不支持蓝牙
return;
}
if(!mBluetoothAdapter.isEnabled()){ //蓝牙未开启，则开启蓝牙
Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
}
//......
public void onActivityResult(int requestCode, int resultCode, Intent data){
if(requestCode == REQUEST_ENABLE_BT){
if(requestCode == RESULT_OK){
//蓝牙已经开启
}
}
}
3。发现蓝牙设备
这里可以细分为几个方面
(1)使本机蓝牙处于可见(即处于易被搜索到状态)，便于其他设备发现本机蓝牙
Java代码
1. //使本机蓝牙在300秒内可被搜索
2. private void
3. if
4. BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
5. new
6. 300);
7. startActivity(discoverableIntent);
8. }
9. }
//使本机蓝牙在300秒内可被搜索
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);
}
}
(2)查找已经配对的蓝牙设备，即以前已经配对过的设备
Java代码
1. Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
2. if (pairedDevices.size() > 0) {
3. findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);
4. for
5. //device.getName() +" "+ device.getAddress());
6. }
7. } else
8. "没有找到已匹对的设备");
9. }
Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);
for (BluetoothDevice device : pairedDevices) {
//device.getName() +" "+ device.getAddress());
}
} else {
mPairedDevicesArrayAdapter.add("没有找到已匹对的设备");
}
(3)通过mBluetoothAdapter.startDiscovery();搜索设备，要获得此搜索的结果需要注册
一个BroadcastReceiver来获取。先注册再获取信息，然后处理
Java代码
1. //注册，当一个设备被发现时调用onReceive
2. IntentFilter filter = new
3. this.registerReceiver(mReceiver, filter);
4.
5. //当搜索结束后调用onReceive
6. filter = new
7. this.registerReceiver(mReceiver, filter);
8. //.......
9. private BroadcastReceiver mReceiver =new
10. @Override
11. public void
12. String action = intent.getAction();
13. if(BluetoothDevice.ACTION_FOUND.equals(action)){
14. BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
15. // 已经配对的则跳过
16. if
17. "\n" + device.getAddress()); //保存设备地址与名字
18. }
19. else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) { //搜索结束
20. if (mNewDevicesArrayAdapter.getCount() ==0) {
21. "没有搜索到设备");
22. }
23. }
24.
25. }
26. };
//注册，当一个设备被发现时调用onReceive
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
this.registerReceiver(mReceiver, filter);
//当搜索结束后调用onReceive
filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
this.registerReceiver(mReceiver, filter);
//.......
private 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);
// 已经配对的则跳过
if (device.getBondState() != BluetoothDevice.BOND_BONDED) {
mNewDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress()); //保存设备地址与名字
}
}else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) { //搜索结束
if (mNewDevicesArrayAdapter.getCount() == 0) {
mNewDevicesArrayAdapter.add("没有搜索到设备");
}
}
}
};
4.建立连接
查找到设备 后，则需要建立本机与其他设备之间的连接。
一般用本机搜索其他蓝牙设备时，本机可以作为一个服务端，接收其他设备的连接。
启动一个服务器端的线程，死循环等待客户端的连接，这与ServerSocket极为相似。
这个线程在准备连接之前启动
Java代码
1. //UUID可以看做一个端口号
2. private staticfinal
3. "fa87c0d0-afac-11de-8a39-0800200c9a66");
4. //像一个服务器一样时刻监听是否有连接建立
5. private class AcceptThreadextends
6. private
7.
8. public AcceptThread(boolean
9. null;
10. try
11. temp = mBluetoothAdapter.listenUsingRfcommWithServiceRecord(
12. NAME_INSECURE, MY_UUID);
13. catch
14. "app", "listen() failed", e);
15. }
16. serverSocket = temp;
17. }
18.
19. public void
20. null;
21. while(true){
22. try
23. socket = serverSocket.accept();
24. catch
25. "app", "accept() failed", e);
26. break;
27. }
28. }
29. if(socket!=null){
30. //此时可以新建一个数据交换线程，把此socket传进去
31. }
32. }
33.
34. //取消监听
35. public void
36. try
37. serverSocket.close();
38. catch
39. "app", "Socket Type" + socketType +"close() of server failed", e);
40. }
41. }
42.
43. }
//UUID可以看做一个端口号
private static final UUID MY_UUID =
UUID.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66");
//像一个服务器一样时刻监听是否有连接建立
private class AcceptThread extends Thread{
private BluetoothServerSocket serverSocket;
public AcceptThread(boolean secure){
BluetoothServerSocket temp = null;
try {
temp = mBluetoothAdapter.listenUsingRfcommWithServiceRecord(
NAME_INSECURE, MY_UUID);
} catch (IOException e) {
Log.e("app", "listen() failed", e);
}
serverSocket = temp;
}
public void run(){
BluetoothSocket socket=null;
while(true){
try {
socket = serverSocket.accept();
} catch (IOException e) {
Log.e("app", "accept() failed", e);
break;
}
}
if(socket!=null){
//此时可以新建一个数据交换线程，把此socket传进去
}
}
//取消监听
public void cancel(){
try {
serverSocket.close();
} catch (IOException e) {
Log.e("app", "Socket Type" + socketType + "close() of server failed", e);
}
}
}
搜索到设备后可以获取设备的地址，通过此地址获取一个BluetoothDeviced对象，可以看做客户端，通过此对象device.createRfcommSocketToServiceRecord(MY_UUID);同一个UUID可与服务器建立连接获取另一个socket对象，由此服务端与客户端各有一个socket对象，此时
他们可以互相交换数据了。
创立客户端socket可建立线程
Java代码
1. //另一个设备去连接本机,相当于客户端
2. private class ConnectThreadextends
3. private
4. private
5. public ConnectThread(BluetoothDevice device,boolean
6. this.device = device;
7. null;
8. try
9. tmp = device.createRfcommSocketToServiceRecord(MY_UUID_SECURE);
10. } catch
11. "app", "create() failed", e);
12. }
13. }
14.
15. public void
16. //取消设备查找
17. try
18. socket.connect();
19. } catch
20. try
21. socket.close();
22. catch
23. "app", "unable to close() "+
24. " socket during connection failure", e1);
25. }
26. //连接失败
27. return;
28. }
29. //此时可以新建一个数据交换线程，把此socket传进去
30. }
31.
32. public void
33. try
34. socket.close();
35. catch
36. "app", "close() of connect socket failed", e);
37. }
38. }
39. }
//另一个设备去连接本机,相当于客户端
private class ConnectThread extends Thread{
private BluetoothSocket socket;
private BluetoothDevice device;
public ConnectThread(BluetoothDevice device,boolean secure){
this.device = device;
BluetoothSocket tmp = null;
try {
tmp = device.createRfcommSocketToServiceRecord(MY_UUID_SECURE);
} catch (IOException e) {
Log.e("app", "create() failed", e);
}
}
public void run(){
mBluetoothAdapter.cancelDiscovery(); //取消设备查找
try {
socket.connect();
} catch (IOException e) {
try {
socket.close();
} catch (IOException e1) {
Log.e("app", "unable to close() "+
" socket during connection failure", e1);
}
connetionFailed(); //连接失败
return;
}
//此时可以新建一个数据交换线程，把此socket传进去
}
public void cancel() {
try {
socket.close();
} catch (IOException e) {
Log.e("app", "close() of connect socket failed", e);
}
}
}
5.建立数据通信线程，进行读取数据
Java代码
1. //建立连接后，进行数据通信的线程
2. private class ConnectedThreadextends
3. private
4. private
5. private
6.
7. public
8.
9. this.socket = socket;
10. try
11. //获得输入输出流
12. inStream = socket.getInputStream();
13. outStream = socket.getOutputStream();
14. catch
15. "app", "temp sockets not created", e);
16. }
17. }
18.
19. public void
20. byte[] buff = newbyte[1024];
21. int len=0;
22. //读数据需不断监听，写不需要
23. while(true){
24. try
25. len = inStream.read(buff);
26. //把读取到的数据发送给UI进行显示
27. Message msg = handler.obtainMessage(BluetoothChat.MESSAGE_READ,
28. 1, buff);
29. msg.sendToTarget();
30. catch
31. "app", "disconnected", e);
32. //失去连接
33. //重新启动服务器
34. break;
35. }
36. }
37. }
38.
39.
40. public void write(byte[] buffer) {
41. try
42. outStream.write(buffer);
43.
44. // Share the sent message back to the UI Activity
45. 1, -1, buffer)
46. .sendToTarget();
47. catch
48. "app", "Exception during write", e);
49. }
50. }
51.
52. public void
53. try
54. socket.close();
55. catch
56. "app", "close() of connect socket failed", e);
57. }
58. }
59. }
//建立连接后，进行数据通信的线程
private class ConnectedThread extends Thread{
private BluetoothSocket socket;
private InputStream inStream;
private OutputStream outStream;
public ConnectedThread(BluetoothSocket socket){
this.socket = socket;
try {
//获得输入输出流
inStream = socket.getInputStream();
outStream = socket.getOutputStream();
} catch (IOException e) {
Log.e("app", "temp sockets not created", e);
}
}
public void run(){
byte[] buff = new byte[1024];
int len=0;
//读数据需不断监听，写不需要
while(true){
try {
len = inStream.read(buff);
//把读取到的数据发送给UI进行显示
Message msg = handler.obtainMessage(BluetoothChat.MESSAGE_READ,
len, -1, buff);
msg.sendToTarget();
} catch (IOException e) {
Log.e("app", "disconnected", e);
connectionLost(); //失去连接
start(); //重新启动服务器
break;
}
}
}
public void write(byte[] buffer) {
try {
outStream.write(buffer);
// Share the sent message back to the UI Activity
handler.obtainMessage(BluetoothChat.MESSAGE_WRITE, -1, -1, buffer)
.sendToTarget();
} catch (IOException e) {
Log.e("app", "Exception during write", e);
}
}
public void cancel() {
try {
socket.close();
} catch (IOException e) {
Log.e("app", "close() of connect socket failed", e);
}
}
}
到这里，蓝牙通信的基本操作已经全部完成。
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