Android 蓝牙开发-传输数据

概述

    传统蓝牙是通过建立REFCCOM sockect来进行通信的，类似于socket通信，一台设备需要开放服务器套接字并处于listen状态，而另一台设备使用服务器的MAC地址发起连接。连接建立后，服务器和客户端就都通过对BluetoothSocket进行读写操作来进行通信。

实现步骤

      要通过蓝牙来传输数据整体流程如下:

首次, 未配对状态

已配对状态

| 关键代码

蓝牙权限

    <uses-permission android:name="android.permission.BLUETOOTH" /><uses-permission android:name="android.permission.BLUETOOTH_CONNECT" /><uses-permission android:name="android.permission.BLUETOOTH_ADMIN" /><uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

打开或关闭蓝牙

BluetoothAdapter ba = BluetoothAdapter.getDefaultAdapter();
ba.enable();
ba.disable();

扫描设备

BluetoothAdapter.getDefaultAdapter().startDiscovery();

监听设备扫描

//Device stae
IntentFilter filter = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
//for discovery .
filter.addAction(BluetoothDevice.ACTION_FOUND);
filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);

根据ACTION_FOUND实时获取扫描到的设备, 常规会获取设备的名称和MAC

BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
String name = device.getName();
String mac = device.getAddress();

| 发起设备配对
| 配对动作大部分情况下, 连接的双方设备都会有对应的弹出窗口, 让用户选择是否配对设备.

public static boolean startPair(BluetoothDevice dev){Logger.d(TAG, "startPair(" + dev.getName() + ")");if(dev != null){try {Method createBond = BluetoothDevice.class.getDeclaredMethod("createBond");if(createBond != null){Object r = createBond.invoke(dev);return (Boolean)r;}} catch (NoSuchMethodException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}}return false;
}

| 连接并发送数据

//获取已绑定的设备
Set<BluetoothDevice> devs = BluetoothAdapter.getDefaultAdapter().getBondedDevices();
BluetoothDevice target = null;//通过名称查找目标设备
for(BluetoothDevice d : devs){if(StringTools.isNotEmpty(d.getName()) && d.getName().startsWith("TARGET-")){target = d;break;}
}if(target != null) {final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00XXXXXXXXXX");try {BluetoothSocket socket = target.createRfcommSocketToServiceRecord(MY_UUID);socket.connect();OutputStream outputStream = socket.getOutputStream();outputStream.write(msg.getBytes());Logger.d(TAG, "sendMsgByBluetooth " + msg);outputStream.flush();InputStream is = socket.getInputStream();byte[] cache = new byte[512];int r = is.read(cache);Logger.d(TAG, "receive response: " + new String(cache));sleepx(500);is.close();outputStream.close();} catch (IOException e) {e.printStackTrace();}
}

基于系统源码的服务端

PS: 源码端可以通过获取system权限, 完成设备配对流程

监听广播并执行配对

   public static final String BLUETOOTH_PARING_QUEST = "android.bluetooth.device.action.PAIRING_REQUEST";@Overridepublic void onReceive(Context context, Intent intent) {BluetoothDevice device = BluetoothTools.onPairRequest(intent);int mType = intent.getIntExtra(BluetoothDevice.EXTRA_PAIRING_VARIANT, BluetoothDevice.ERROR);int mPasskey = intent.getIntExtra(BluetoothDevice.EXTRA_PAIRING_KEY, BluetoothDevice.ERROR);BluetoothTools.pair(device, mType, mPasskeyFormatted);}

BluetoothTools.java (反射系统蓝牙部分接口)

private static void setRemoteOutOfBandData(BluetoothDevice dev){try {Method setRemoteOutOfBandData = BluetoothDevice.class.getDeclaredMethod("setRemoteOutOfBandData");if(setRemoteOutOfBandData != null){setRemoteOutOfBandData.invoke(dev);}} catch (NoSuchMethodException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}}private static void setPairingConfirmation(BluetoothDevice dev, boolean bool){try {Method setPairingConfirmation = BluetoothDevice.class.getDeclaredMethod("setPairingConfirmation", Boolean.TYPE);if(setPairingConfirmation != null){setPairingConfirmation.invoke(dev, bool);}} catch (NoSuchMethodException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}}private static void setPasskey(BluetoothDevice dev, int passKey){try {Method setPasskey = BluetoothDevice.class.getDeclaredMethod("setPasskey", Integer.TYPE);if(setPasskey != null){setPasskey.invoke(dev, passKey);}} catch (NoSuchMethodException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}}private static byte[] convertPinToBytes(String val){try {Method convertPinToBytes = BluetoothDevice.class.getDeclaredMethod("convertPinToBytes", String.class);if(convertPinToBytes != null){return (byte[])convertPinToBytes.invoke(null, val);}} catch (NoSuchMethodException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}return null;}private static void setPin(BluetoothDevice mDevice, byte[] bytes){try {Method setPin = BluetoothDevice.class.getDeclaredMethod("setPin", byte[].class);if(setPin != null){setPin.invoke(mDevice, (Object)bytes);}} catch (NoSuchMethodException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}}public static void pair(BluetoothDevice dev, int type, String password){onPair(type, password, dev);}private static void onPair(int mType, String value, BluetoothDevice mDevice) {switch (mType) {case BluetoothDevice.PAIRING_VARIANT_PIN:byte[] pinBytes = convertPinToBytes(value);if (pinBytes == null) {return;}setPin(mDevice, pinBytes);break;case PAIRING_VARIANT_PASSKEY:int passkey = Integer.parseInt(value);setPasskey(mDevice, passkey);break;case BluetoothDevice.PAIRING_VARIANT_PASSKEY_CONFIRMATION:case PAIRING_VARIANT_CONSENT:setPairingConfirmation(mDevice, true);break;case PAIRING_VARIANT_DISPLAY_PASSKEY:case PAIRING_VARIANT_DISPLAY_PIN:// Do nothing.break;case PAIRING_VARIANT_OOB_CONSENT:setRemoteOutOfBandData(mDevice);break;default:Logger.e(TAG, "Incorrect pairing type received");}}

同样, 在完成配对后, 可以通过BluetoothServerSocket 来接收来自客户端的连接实现通讯:

final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00XXXXXXXXXX");
BluetoothServerSocket serverSocket = BluetoothAdapter.listenUsingRfcommWithServiceRecord("MyApp", MY_UUID);
Logger.d(TAG, "listen: waiting for new connect...");
BluetoothSocket clientSocket = serverSocket.accept();
InputStream inputStream = mSocket.getInputStream();
byte[] cache = new byte[512];
inputStream.read(cache);
//省略读写和关闭代码...

• 关于UUID

  UUID.fromString 方法用于将字符串转换为 UUID 对象。UUID（通用唯一标识符）是一个 128 位的值，通常表示为 32 个十六进制数字，分为五组，形式为 8-4-4-4-12 的字符串。

  字符串格式要求如下：

  1. 长度必须是 36 个字符。
  2. 字符串必须以连字符（-）分隔为五组，每组字符数分别为 8、4、4、4 和 12。
  3. 所有字符都必须是十六进制数字（0-9 和 a-f 或 A-F）。

  示例：

  import java.util.UUID;public class Main {public static void main(String[] args) {String uuidString = "123e4567-e89b-12d3-a456-426614174000";UUID uuid = UUID.fromString(uuidString);System.out.println("UUID: " + uuid);}
  }

  如果你尝试使用不符合格式的字符串，UUID.fromString 方法将抛出 IllegalArgumentException。例如：

  import java.util.UUID;public class Main {public static void main(String[] args) {String invalidUuidString = "123e4567-e89b-12d3-a456-4266141740"; // 缺少一个字符try {UUID uuid = UUID.fromString(invalidUuidString);System.out.println("UUID: " + uuid);} catch (IllegalArgumentException e) {System.out.println("Invalid UUID string: " + invalidUuidString);}}
  }

  在这个例子中，invalidUuidString 不符合 UUID 字符串格式要求，因此 UUID.fromString 方法将抛出 IllegalArgumentException。
  PS:UUID对字符大小写不敏感

参考系统源码 packages/apps/Settings
配对窗口: AndroidManifest.xml

<activity android:name=".bluetooth.BluetoothPairingDialog"android:excludeFromRecents="true"android:windowSoftInputMode="stateVisible|adjustResize"android:theme="@*android:style/Theme.DeviceDefault.Settings.Dialog.NoActionBar"><intent-filter android:priority="1"><action android:name="android.bluetooth.device.action.PAIRING_REQUEST" /><category android:name="android.intent.category.DEFAULT" /></intent-filter></activity>

src/com/android/settings/bluetooth/BluetoothParingController.java
src/com/android/settings/bluetooth/BluetoothParingDialogFragment.java

参考

android蓝牙开发 蓝牙设备的查找和连接
Android蓝牙通信机制详解