Android 蓝牙开发实例解析
在使用手机时，蓝牙通信给我们带来很多方便。那么在android手机中怎样进行蓝牙开发呢？本文以实例的方式讲解android蓝牙开发的知识。
1、使用蓝牙的响应权限
xml/html代码
<uses-permission android:name="android.permission.bluetooth"/> <uses-permission android:name="android.permission.bluetooth_admin"/>
2、配置本机蓝牙模块
在这里首先要了解对蓝牙操作一个核心类bluetoothadapter。
bluetoothadapter adapter = bluetoothadapter.getdefaultadapter(); //直接打开系统的蓝牙设置面板 intent intent = new intent(bluetoothadapter.action_request_enable); startactivityforresult(intent, 0x1); //直接打开蓝牙 adapter.enable(); //关闭蓝牙 adapter.disable(); //打开本机的蓝牙发现功能（默认打开120秒，可以将时间最多延长至300秒） intent discoveryintent = new intent(bluetoothadapter.action_request_discoverable); discoverableintent.putextra(bluetoothadapter.extra_discoverable_duration, 300);//设置持续时间（最多300秒）
3、搜索蓝牙设备
使用bluetoothadapter的startdiscovery()方法来搜索蓝牙设备。
startdiscovery()方法是一个异步方法，调用后会立即返回。该方法会进行对其他蓝牙设备的搜索，该过程会持续12秒。该方法调用后，搜索过程实际上是在一个system service中进行的，所以可以调用canceldiscovery()方法来停止搜索（该方法可以在未执行discovery请求时调用）。
请求discovery后，系统开始搜索蓝牙设备，在这个过程中，系统会发送以下三个广播：
action_discovery_start：开始搜索
action_discovery_finished：搜索结束
action_found：找到设备，这个intent中包含两个extra fields：extra_device和extra_class，分别包含bluetoodevice和bluetoothclass。
我们可以自己注册相应的broadcastreceiver来接收响应的广播，以便实现某些功能。
// 创建一个接收action_found广播的broadcastreceiver
private final broadcastreceiver mreceiver = new broadcastreceiver() {
public void onreceive(context context, intent intent) {
string action = intent.getaction();
// 发现设备
if (bluetoothdevice.action_found.equals(action)) {
// 从intent中获取设备对象
bluetoothdevice device = intent.getparcelableextra(bluetoothdevice.extra_device);
// 将设备名称和地址放入array adapter，以便在listview中显示
marrayadapter.add(device.getname() + "\n" + device.getaddress());
}
}
};
// 注册broadcastreceiver
intentfilter filter = new intentfilter(bluetoothdevice.action_found);
registerreceiver(mreceiver, filter); // 不要忘了之后解除绑定
4、蓝牙socket通信
如果打算建议两个蓝牙设备之间的连接，则必须实现服务器端与客户端的机制。当两个设备在同一个rfcomm channel下分别拥有一个连接的bluetoothsocket，这两个设备才可以说是建立了连接。
服务器设备与客户端设备获取bluetoothsocket的途径是不同的。服务器设备是通过accepted一个incoming connection来获取的，而客户端设备则是通过打开一个到服务器的rfcomm channel来获取的。
服务器端的实现
通过调用bluetoothadapter的listenusingrfcommwithservicerecord(string, uuid)方法来获取bluetoothserversocket（uuid用于客户端与服务器端之间的配对）。
调用bluetoothserversocket的accept()方法监听连接请求，如果收到请求，则返回一个bluetoothsocket实例（此方法为block方法，应置于新线程中）。
如果不想在accept其他的连接，则调用bluetoothserversocket的close()方法释放资源（调用该方法后，之前获得的bluetoothsocket实例并没有close。但由于rfcomm一个时刻只允许在一条channel中有一个连接，则一般在accept一个连接后，便close掉bluetoothserversocket）。
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 = mbluetoothadapter.listenusingrfcommwithservicerecord(name, my_uuid);
} catch (ioexception 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) {
break;
}
// if a connection was accepted
if (socket != null) {
// do work to manage the connection (in a separate thread)
manageconnectedsocket(socket);
mmserversocket.close();
break;
}
}
}
/** will cancel the listening socket, and cause the thread to finish */
public void cancel() {
try {
mmserversocket.close();
} catch (ioexception e) { }
}
}
客户端的实现
通过搜索得到服务器端的bluetoothservice。
调用bluetoothservice的listenusingrfcommwithservicerecord(string, uuid)方法获取bluetoothsocket（该uuid应该同于服务器端的uuid）。
调用bluetoothsocket的connect()方法（该方法为block方法），如果uuid同服务器端的uuid匹配，并且连接被服务器端accept，则connect()方法返回。
注意：在调用connect()方法之前，应当确定当前没有搜索设备，否则连接会变得非常慢并且容易失败。
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;
// get a bluetoothsocket to connect with the given bluetoothdevice
try {
// my_uuid is the app's uuid string, also used by the server code
tmp = device.createrfcommsockettoservicerecord(my_uuid);
} catch (ioexception e) { }
mmsocket = tmp;
}
public void run() {
// cancel discovery because it will slow down the connection
mbluetoothadapter.canceldiscovery();
try {
// connect the device through the socket. this will block
// until it succeeds or throws an exception
mmsocket.connect();
} catch (ioexception connectexception) {
// unable to connect; close the socket and get out
try {
mmsocket.close();
} catch (ioexception closeexception) { }
return;
}
// do work to manage the connection (in a separate thread)
manageconnectedsocket(mmsocket);
}
/** will cancel an in-progress connection, and close the socket */
public void cancel() {
try {
mmsocket.close();
} catch (ioexception e) { }
}
}
5、连接管理（数据通信）
分别通过bluetoothsocket的getinputstream()和getoutputstream()方法获取inputstream和outputstream。
使用read(bytes[])和write(bytes[])方法分别进行读写操作。
注意：read(bytes[])方法会一直block，知道从流中读取到信息，而write(bytes[])方法并不是经常的block（比如在另一设备没有及时read或者中间缓冲区已满的情况下，write方法会block）。
private class connectedthread extends thread {
private final bluetoothsocket mmsocket;
private final inputstream mminstream;
private final outputstream mmoutstream;
public connectedthread(bluetoothsocket socket) {
mmsocket = socket;
inputstream tmpin = null;
outputstream tmpout = null;
// get the input and output streams, using temp objects because
// member streams are final
try {
tmpin = socket.getinputstream();
tmpout = socket.getoutputstream();
} catch (ioexception e) { }
mminstream = tmpin;
mmoutstream = tmpout;
}
public void run() {
byte[] buffer = new byte[1024]; // buffer store for the stream
int bytes; // bytes returned from read()
// keep listening to the inputstream until an exception occurs
while (true) {
try {
// read from the inputstream
bytes = mminstream.read(buffer);
// send the obtained bytes to the ui activity
mhandler.obtainmessage(message_read, bytes, -1, buffer)
.sendtotarget();
} catch (ioexception e) {
break;
}
}
}
/* call this from the main activity to send data to the remote device */
public void write(byte[] bytes) {
try {
mmoutstream.write(bytes);
} catch (ioexception e) { }
}
/* call this from the main activity to shutdown the connection */
public void cancel() {
try {
mmsocket.close();
} catch (ioexception e) { }
}
}
以上就android 蓝牙的开发简单示例代码，后续继续整理相关资料，谢谢大家对本站的支持！