简述
在项目中也曾用到安卓蓝牙，主要是与蓝牙模块进行通信，所以简单的进行总结，做下笔记，以备不时之需。
开启与设置蓝牙
获取一个BluetoothAdapter，通过getDefaultAdapter()获取默认蓝牙适配器或者自己指定。其次检测蓝牙是否打开，如若没有打开，则通过适配器的.enable()开启。还可以自定义蓝牙设备的可见性以及其时间。
private void search() {
BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
if (!adapter.isEnabled()) {
adapter.enable();
}
Intent enable = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
enable.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 3600); //3600为蓝牙设备可见时间
startActivity(enable);
Intent searchIntent = new Intent(this, ComminuteActivity.class);
startActivity(searchIntent);
}
搜索想要通信的设备
private class BluetoothReceiver extends 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 (isLock(device)) {
devices.add(device.getName());
}
deviceList.add(device);
}
showDevices();
}
}
private boolean isLock(BluetoothDevice device) {
boolean isLockName = (device.getName()).equals(lockName);
boolean isSingleDevice = devices.indexOf(device.getName()) == -1;
return isLockName && isSingleDevice;
}
并进行连接
public void connect(final String message) {
Thread thread = new Thread(new Runnable() {
public void run() {
BluetoothSocket tmp = null;
Method method;
try {
method = device.getClass().getMethod("createRfcommSocket", new Class[]{int.class});
tmp = (BluetoothSocket) method.invoke(device, 1);
} catch (Exception e) {
setState(CONNECT_FAILED);
Log.e("TAG", e.toString());
}
socket = tmp;
try {
socket.connect();
isConnect = true;
} catch (Exception e) {
setState(CONNECT_FAILED);
Log.e("TAG", e.toString());
}
}
}
在此前，记得调用bluetoothAdapter.startDiscovery();方法。他会对其他蓝牙设备进行搜索，持续12秒，通过cancelDiscovery()取消。在搜索蓝牙设备的过程中，系统可能会发送以下三个广播：ACTION_DISCOVERY_START(开始搜索)，ACTION_DISCOVERY_FINISHED(搜索结束)和ACTION_FOUND(找到设备)。ACTION_FOUND这个才是我们想要的，这个Intent中包含两个extra fields:EXTRA_DEVICE和EXTRA_CLASS，包含的分别是BluetoothDevice和BluetoothClass，BluetoothDevice中的EXTRA_DEVICE就是我们搜索到的设备对象。 确认搜索到设备后，我们可以从得到的BluetoothDevice对象中获得设备的名称和地址。
连接设备之前需要uuid，用来配对，是一个128位的字符串id，用于表示。
注册广播与撤销
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
receiver = new BluetoothReceiver();
registerReceiver(receiver, filter);
//撤销
@Override
protected void onDestroy() {
unregisterReceiver(receiver);
super.onDestroy();
}
进行通信
如果链接没有问题，就能够进行通信了。
if (isConnect) {
try {
OutputStream outStream = socket.getOutputStream();
outStream.write(getHexBytes(message));
} catch (IOException e) {
setState(WRITE_FAILED);
Log.e("TAG", e.toString());
}
try {
InputStream inputStream = socket.getInputStream();
int data;
while (true) {
try {
data = inputStream.read();
Message msg = handler.obtainMessage();
msg.what = DATA;
msg.arg1 = data;
handler.sendMessage(msg);
} catch (IOException e) {
setState(READ_FAILED);
Log.e("TAG", e.toString());
break;
}
}
} catch (IOException e) {
setState(WRITE_FAILED);
Log.e("TAG", e.toString());
}
}
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
Log.e("TAG", e.toString());
}
}
}
}
将字符串转化为16进制：
private byte[] getHexBytes(String message) {
int len = message.length() / 2;
char[] chars = message.toCharArray();
String[] hexStr = new String[len];
byte[] bytes = new byte[len];
for (int i = 0, j = 0; j < len; i += 2, j++) {
hexStr[j] = "" + chars[i] + chars[i + 1];
bytes[j] = (byte) Integer.parseInt(hexStr[j], 16);
}
return bytes;
}
