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。

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