Android为蓝牙设备之间的通信封装好了一些调用接口,使得实现Android的蓝牙通信功能并不困难。可通过UUID使两个设备直接建立连接。
具体步骤:
1. 获取BluetoothAdapter实例,注册一个BroadcastReceiver监听蓝牙扫描过程中的状态变化
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mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); |
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IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mReceiver, filter); |
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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
// 通过EXTRA_DEVICE附加域来得到一个BluetoothDevice设备
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
// If it's already paired, skip it, because it's been listed already
// 如果这个设备是不曾配对过的,添加到list列表
if (device.getBondState() != BluetoothDevice.BOND_BONDED)
{
list.add( new ChatMessage(device.getName() + "\n" + device.getAddress(), false ));
clientAdapter.notifyDataSetChanged();
mListView.setSelection(list.size() - 1 );
}
// When discovery is finished, change the Activity title
}
else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action))
{
setProgressBarIndeterminateVisibility( false );
if (mListView.getCount() == 0 )
{
list.add( new ChatMessage( "没有发现蓝牙设备" , false ));
clientAdapter.notifyDataSetChanged();
mListView.setSelection(list.size() - 1 );
}
}
}
};
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2. 打开蓝牙(enable),并设置蓝牙的可见性(可以被其它设备扫描到,客户端是主动发请求的,可不设置,服务端必须设置可见)。
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if (mBluetoothAdapter != null ) {
if (!mBluetoothAdapter.isEnabled()) {
// 发送打开蓝牙的意图,系统会弹出一个提示对话框
Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent, RESULT_FIRST_USER);
// 设置蓝牙的可见性,最大值3600秒,默认120秒,0表示永远可见(作为客户端,可见性可以不设置,服务端必须要设置)
Intent displayIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
displayIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 0 );
startActivity(displayIntent);
// 直接打开蓝牙
mBluetoothAdapter.enable();
}
} |
3. 扫描,startDiscovery()方法是一个很耗性能的操作,在扫描之前可以先使用getBondedDevices()获取已经配对过的设备(可直接连接),避免不必要的消耗。
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private void scanDevice() {
// TODO Auto-generated method stub
if (mBluetoothAdapter.isDiscovering()) {
mBluetoothAdapter.cancelDiscovery();
} else {
// 每次扫描前都先判断一下是否存在已经配对过的设备
Set<bluetoothdevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0 ) {
for (BluetoothDevice device : pairedDevices) {
list.add( new ChatMessage(device.getName() + "\n" + device.getAddress(), true ));
}
} else {
list.add( new ChatMessage( "No devices have been paired" , true ));
clientAdapter.notifyDataSetChanged();
mListView.setSelection(list.size() - 1 );
}
/* 开始搜索 */
mBluetoothAdapter.startDiscovery();
}
}</bluetoothdevice> |
4. 通过Mac地址发送连接请求,在这之前必须使用cancelDiscovery()方法停止扫描。
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mBluetoothAdapter.cancelDiscovery();
// 通过Mac地址去尝试连接一个设备 BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(BluetoothMsg.BlueToothAddress); |
5. 通过UUID使两个设备之间建立连接。
客户端:主动发请求
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BluetoothSocket socket = device.createRfcommSocketToServiceRecord(UUID.fromString( "00001101-0000-1000-8000-00805F9B34FB" ));
// 通过socket连接服务器,这是一个阻塞过程,直到连接建立或者连接失效 socket.connect(); |
服务端:接受一个请求
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BluetoothServerSocket mServerSocket = mBluetoothAdapter.listenUsingRfcommWithServiceRecord(PROTOCOL_SCHEME_RFCOMM, UUID.fromString( "00001101-0000-1000-8000-00805F9B34FB" ));
/* 接受客户端的连接请求 */ // 这是一个阻塞过程,直到建立一个连接或者连接失效 // 通过BluetoothServerSocket得到一个BluetoothSocket对象,管理这个连接 BluetoothSocket socket = mServerSocket.accept(); |
6. 通过InputStream/outputStream读写数据流,已达到通信目的。
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OutputStream os = socket.getOutputStream(); os.write(msg.getBytes()); |
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InputStream is = null ;
try {
is = socket.getInputStream();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} |
7. 关闭所有线程以及socket,并关闭蓝牙设备(disable)。
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if (mClientThread != null ) {
mClientThread.interrupt();
mClientThread = null ;
} if (mReadThread != null ) {
mReadThread.interrupt();
mReadThread = null ;
} try {
if (socket != null ) {
socket.close();
socket = null ;
}
} catch (IOException e) {
// TODO: handle exception
} |
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if (mBluetoothAdapter != null ) {
mBluetoothAdapter.cancelDiscovery();
// 关闭蓝牙
mBluetoothAdapter.disable();
} unregisterReceiver(mReceiver); |
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