Android 蓝牙操作详解
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1.启用蓝牙并使设备处于可发现状态
1.1 在使用BluetoothAdapter类的实例进操作之前,应启用isEnable()方法检查设备是否启用了蓝牙适配器。
// 使用意图提示用户启用蓝牙,并使设备处于可发现状态
private void startBluetooth() {
BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
// 检测蓝牙是否开启
if (!bt.isEnabled()) {
Intent enableIntent = new Intent(
BluetoothAdapter. ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
}
}
1.2返回意图活动时,调用onActivityResult(),可以提取主设备名称和mac地址
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == REQUEST_ENABLE_BT
&& resultCode == Activity. RESULT_OK) {
BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
String address = bt.getAddress();
String name = bt.getName();
String toastText = name + " :" + address;
Toast. makeText(this, toastText, Toast.LENGTH_LONG).show();
discoverable();
}
}
1.3 请求用户授权,让设备可被其它临近设备发现:
// 请求用户授权,让设备在120秒内处于可发现状态
private void discoverable() {
Intent discoverableIntent = new Intent(
BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
startActivity(discoverableIntent);
}
2.连接启用蓝牙设备
2.1对于任何蓝牙应用,都必须在androidManifst.xml中添加如下权限:
<uses-permission android:name= "android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name= "android.permission.BLUETOOTH" />
2.2 创建到其他蓝牙设备的套接字连接
我们应该在一个线程内持续监听套接字流中的数据。可以在该线程外写入连接的流。这种连接是一个阻塞调用,由于蓝牙设备发现是一个缓慢的过程,可能降低连接速率。所以,在连接其它设备之前要取消设备发现。
蓝牙套接字连接时阻塞调用,只在连接成功或者连接设备发生异常时才会返回。BluetoothConnection一经实例化,就会创建到其他设备的连接,并开始监听来自连接设备的数据。
package com.example.blueoothdemo;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
/**
* 读写蓝牙设备
*
* @author hbbliyong
*
*/
public class BluetoothConnecion extends Thread {
private final BluetoothSocket mSocket;
private final InputStream mInStream;
private final OutputStream mOutStream;
byte[] buffer;
private final BluetoothAdapter mAdapter;
// 用于本应用程序唯一的UUID,
private static final UUID MY_UUID = UUID
.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66");
public BluetoothConnecion(BluetoothDevice device) {
BluetoothSocket tmp = null;
mAdapter = BluetoothAdapter.getDefaultAdapter();
// 获得用于指定蓝牙连接的BluetoothSocket
try {
tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (Exception e) {
e.printStackTrace();
}
mSocket = tmp;
// 在新线程中建立套接字连接,避免FC
Thread connectionThread = new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
// 始终取消发现,因为它会降低连接的速度
mAdapter.cancelDiscovery();
// 建立到BluetoothSocket的连接
try {
// 这是一个阻塞调用,只在成功连接或者异常时返回
mSocket.connect();
} catch (Exception e) {
e.printStackTrace();
// 设备连接失败,关闭套接字
try {
mSocket.close();
} catch (Exception e2) {
// TODO: handle exception
e2.printStackTrace();
}
}
}
});
connectionThread.start();
InputStream tmpIn = null;
OutputStream tmpOut = null;
// 获得BluetoothSoket输入输出流
try {
tmpIn = mSocket.getInputStream();
tmpOut = mSocket.getOutputStream();
buffer = new byte[1024];
} catch (Exception e) {
e.printStackTrace();
}
mInStream = tmpIn;
mOutStream = tmpOut;
}
public void run() {
// 连接时保持监听InputStream
while (true) {
try {
// 从套接字流读取数据
mInStream.read(buffer);
// 向UI Activity发送获取的数据
} catch (Exception e) {
// TODO: handle exception
// 这里的异常标志着连接的丢失
// 向UI Activity发送获取的数据
break;
}
}
}
public void write(byte[] buffer)
{
try {
mOutStream.write(buffer);
} catch (Exception e) {
e.printStackTrace();
}
}
public void cancel()
{
try {
mSocket.close();
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
/**
* 读写蓝牙设备
*
* @author hbbliyong
*
*/
public class BluetoothConnecion extends Thread {
private final BluetoothSocket mSocket;
private final InputStream mInStream;
private final OutputStream mOutStream;
byte[] buffer;
private final BluetoothAdapter mAdapter;
// 用于本应用程序唯一的UUID,
private static final UUID MY_UUID = UUID
.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66");
public BluetoothConnecion(BluetoothDevice device) {
BluetoothSocket tmp = null;
mAdapter = BluetoothAdapter.getDefaultAdapter();
// 获得用于指定蓝牙连接的BluetoothSocket
try {
tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (Exception e) {
e.printStackTrace();
}
mSocket = tmp;
// 在新线程中建立套接字连接,避免FC
Thread connectionThread = new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
// 始终取消发现,因为它会降低连接的速度
mAdapter.cancelDiscovery();
// 建立到BluetoothSocket的连接
try {
// 这是一个阻塞调用,只在成功连接或者异常时返回
mSocket.connect();
} catch (Exception e) {
e.printStackTrace();
// 设备连接失败,关闭套接字
try {
mSocket.close();
} catch (Exception e2) {
// TODO: handle exception
e2.printStackTrace();
}
}
}
});
connectionThread.start();
InputStream tmpIn = null;
OutputStream tmpOut = null;
// 获得BluetoothSoket输入输出流
try {
tmpIn = mSocket.getInputStream();
tmpOut = mSocket.getOutputStream();
buffer = new byte[1024];
} catch (Exception e) {
e.printStackTrace();
}
mInStream = tmpIn;
mOutStream = tmpOut;
}
public void run() {
// 连接时保持监听InputStream
while (true) {
try {
// 从套接字流读取数据
mInStream.read(buffer);
// 向UI Activity发送获取的数据
} catch (Exception e) {
// TODO: handle exception
// 这里的异常标志着连接的丢失
// 向UI Activity发送获取的数据
break;
}
}
}
public void write(byte[] buffer)
{
try {
mOutStream.write(buffer);
} catch (Exception e) {
e.printStackTrace();
}
}
public void cancel()
{
try {
mSocket.close();
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
3.监听和接收蓝牙连接请求
在两个蓝牙设备交互之前,其中一个通信设备必须起服务器的作用。它获取一个BluetoothServerSocket实例并监听入站请求。这个实例通过调用蓝牙适配器上的listenUsingRfcommWithServiceRecord()方法获得。有了这个实例我们可以通过start()方法开始监听来自远程设备的入站请求。
//使主设备处于可发现状态
Intent disCoverableIntent = new Intent(
BluetoothAdapter. ACTION_REQUEST_DISCOVERABLE);
startActivityForResult(disCoverableIntent,DISCOVERY_REQUEST_BLUETOOTH );
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == DISCOVERY_REQUEST_BLUETOOTH ) {
boolean isDiscoverable = resultCode > 0;
if (isDiscoverable) {
// UUID
// uuid=UUID.fromString("a60f35f0-b93a-11de-8a39-08002009c666");
final UUID uuid = UUID.randomUUID();
final String serverName = "BTServer" ;
final BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
final BluetoothServerSocket bluetoothServer;
Thread listenThread = new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
try {
bluetoothServer = bt.listenUsingRfcommWithServiceRecord(serverName, uuid);
BluetoothSocket serverSocket = bluetoothServer.accept();
myHandleConnectionWiht(serverSocket);
} catch (Exception e) {
e.printStackTrace();
}
}
private void myHandleConnectionWiht(
BluetoothSocket serverSocket) {
// TODO Auto-generated method stub
}
});
listenThread.start();
}
}
}
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