Android蓝牙操作
Android蓝牙操作
android
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
<uses-permissionandroid:name="android.permission.BLUETOOTH"/>
<uses-permissionandroid: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
BluetoothAdaptermBluetoothAdapter=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
IntentenableIntent=newIntent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent,REQUEST_ENABLE_BT);
}
//......
publicvoidonActivityResult(intrequestCode,intresultCode,Intentdata){
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
//使本机蓝牙在300秒内可被搜索
privatevoidensureDiscoverable(){
if(mBluetoothAdapter.getScanMode()!=
BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE){
IntentdiscoverableIntent=newIntent(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
Set<BluetoothDevice>pairedDevices=mBluetoothAdapter.getBondedDevices();
if(pairedDevices.size()>0){
findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);
for(BluetoothDevicedevice: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
//注册,当一个设备被发现时调用onReceive
IntentFilterfilter=newIntentFilter(BluetoothDevice.ACTION_FOUND);
this.registerReceiver(mReceiver,filter);
//当搜索结束后调用onReceive
filter=newIntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
this.registerReceiver(mReceiver,filter);
//.......
privateBroadcastReceivermReceiver=newBroadcastReceiver(){
@Override
publicvoidonReceive(Contextcontext,Intentintent){
Stringaction=intent.getAction();
if(BluetoothDevice.ACTION_FOUND.equals(action)){
BluetoothDevicedevice=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
}
}elseif(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
//UUID可以看做一个端口号
privatestaticfinalUUIDMY_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
privateclassAcceptThreadextendsThread{
privateBluetoothServerSocketserverSocket;
publicAcceptThread(booleansecure){
BluetoothServerSockettemp=null;
try{
temp=mBluetoothAdapter.listenUsingRfcommWithServiceRecord(
NAME_INSECURE,MY_UUID);
}catch(IOExceptione){
Log.e("app","listen()failed",e);
}
serverSocket=temp;
}
publicvoidrun(){
BluetoothSocketsocket=null;
while(true){
try{
socket=serverSocket.accept();
}catch(IOExceptione){
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
publicvoidcancel(){
try{
serverSocket.close();
}catch(IOExceptione){
Log.e("app","SocketType"+socketType+"close()ofserverfailed",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
//另一个设备去连接本机,相当于客户端
privateclassConnectThreadextendsThread{
privateBluetoothSocketsocket;
privateBluetoothDevicedevice;
publicConnectThread(BluetoothDevicedevice,booleansecure){
this.device=device;
BluetoothSockettmp=null;
try{
tmp=device.createRfcommSocketToServiceRecord(MY_UUID_SECURE);
}catch(IOExceptione){
Log.e("app","create()failed",e);
}
}
publicvoidrun(){
mBluetoothAdapter.cancelDiscovery();//取消设备查找
try{
socket.connect();
}catch(IOExceptione){
try{
socket.close();
}catch(IOExceptione1){
Log.e("app","unabletoclose()"+
"socketduringconnectionfailure",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
}
publicvoidcancel(){
try{
socket.close();
}catch(IOExceptione){
Log.e("app","close()ofconnectsocketfailed",e);
}
}
}
5.建立数据通信线程,进行读取数据
Java代码
//建立连接后,进行数据通信的线程
privateclassConnectedThreadextendsThread{
privateBluetoothSocketsocket;
privateInputStreaminStream;
privateOutputStreamoutStream;
publicConnectedThread(BluetoothSocketsocket){
this.socket=socket;
try{
//获得输入输出流
inStream=socket.getInputStream();
outStream=socket.getOutputStream();
}catch(IOExceptione){
Log.e("app","tempsocketsnotcreated",e);
}
}
publicvoidrun(){
byte[]buff=newbyte[1024];
intlen=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
Messagemsg=handler.obtainMessage(BluetoothChat.MESSAGE_READ,
len,-1,buff);
msg.sendToTarget();
}catch(IOExceptione){
Log.e("app","disconnected",e);
connectionLost();//失去连接
start();//重新启动服务器
break;
}
}
}
publicvoidwrite(byte[]buffer){
try{
outStream.write(buffer);
//SharethesentmessagebacktotheUIActivity
handler.obtainMessage(BluetoothChat.MESSAGE_WRITE,-1,-1,buffer)
.sendToTarget();
}catch(IOExceptione){
Log.e("app","Exceptionduringwrite",e);
}
}
publicvoidcancel(){
try{
socket.close();
}catch(IOExceptione){
Log.e("app","close()ofconnectsocketfailed",e);
}
}
}
到这里,蓝牙通信的基本操作已经全部完成。