Android蓝牙操作笔记
16lz
2022-07-31
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
- <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
- 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
- //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
- 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
- //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
- //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
- //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
- //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。
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