android BLE Peripheral 模拟 ibeacon 发出ble 广播

Android对外模模式(peripheral)的支持：

从Android 5.0＋开始才支持。 api level >= 21

所以5.0 之前设备，是不能向外发送广播的。

Android中心设备(central)的支持：

从Android 4.3+ 。 api level  >= 18

1、初始化蓝牙

2、检查ble是否可用

3、开启广播

4、扫描响应数据

5、创建iBeacon 广播数据

6、广播设置

7、开启广播后的回调

（1）初始化蓝牙：

添加权限：

     <uses-permission android:name="android.permission.BLUETOOTH" />
     <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
     <!-- 6.0之后蓝牙还需要地理位置权限 -->
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

     <!-- 自行判断 -->
     <uses-feature
         android:name="android.hardware.bluetooth_le"
         android:required="false" />

初始化：

 //初始化BluetoothManager和BluetoothAdapter
  if (mBluetoothManager == null) {
      mBluetoothManager = (BluetoothManager) mContext.getSystemService(BLUETOOTH_SERVICE);
  }

  if (mBluetoothManager != null && mBluetoothAdapter == null) {
      mBluetoothAdapter = mBluetoothManager.getAdapter();
  }

（2）检查是否可使用ble：

 if (!activity.getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
    Toast.makeText(activity, "不支持ble", Toast.LENGTH_LONG).show();    return;
 }

 final BluetoothManager mBluetoothManager = (BluetoothManager) activity.getSystemService(BLUETOOTH_SERVICE);
 mBluetoothAdapter = mBluetoothManager.getAdapter();

 if (mBluetoothAdapter == null) {
    Toast.makeText(activity, "不支持ble", Toast.LENGTH_LONG).show();    return;
 }
 // 获取蓝牙ble广播
16 mBluetoothAdvertiser = mBluetoothAdapter.getBluetoothLeAdvertiser();
 if (mBluetoothAdvertiser == null) {
    Toast.makeText(activity, "the device not support peripheral", Toast.LENGTH_SHORT).show();
    Log.e(TAG, "the device not support peripheral");    return;
 }

（3）开启广播：

public void startAdvertising(MockServerCallBack callBack) {
        //获取BluetoothLeAdvertiser，BLE发送BLE广播用的一个API
        if (mBluetoothAdvertiser == null) {
            mBluetoothAdvertiser = mBluetoothAdapter.getBluetoothLeAdvertiser();
        }
        if (mBluetoothAdvertiser != null) {try {
                //创建BLE beacon Advertising并且广播
                mBluetoothAdvertiser.startAdvertising(createAdvSettings(true, 0)
                        , createIBeaconAdvertiseData(BluetoothUUID.bleServerUUID,
                                mMajor, mMinor, mTxPower)
                        , createScanAdvertiseData(mMajor, mMinor, mTxPower, mAdvCallback);
            } catch (Exception e) {
                Log.v(TAG, "Fail to setup BleService");
            }
        }
    }

一个ble广播包：广播数据其实包含两部分：Advertising Data（广播数据） 和 Scan Response Data（扫描响应数据）。

通常情况下，广播的一方，按照一定的间隔，往空中广播 Advertising Data。

当某个监听设备监听到这个广播数据时候，会通过发送 Scan Response Request，请求广播方发送扫描响应数据数据。

这两部分数据的长度都是固定的 31 字节。

在 Android 中，系统会把这两个数据拼接在一起，返回一个 62 字节的数组。

（4）扫描响应数据：

可以自定义数据，比如增加湿度，温度等。

     //设置scan广播数据
     public static AdvertiseData createScanAdvertiseData(short major, short minor, byte txPower) {
         AdvertiseData.Builder builder = new AdvertiseData.Builder();
         builder.setIncludeDeviceName(true);

         byte[] serverData = new byte[5];
         ByteBuffer bb = ByteBuffer.wrap(serverData);
         bb.order(ByteOrder.BIG_ENDIAN);
         bb.putShort(major);
         bb.putShort(minor);
         bb.put(txPower);
         builder.addServiceData(ParcelUuid.fromString(BluetoothUUID.bleServerUUID.toString())
                 , serverData);

         AdvertiseData adv = builder.build();
         return adv;
     }

5、创建ibeacon 广播数据。

iBeacon 的广播结构：iBeacon 只是协议.

• the 2 byte beacon identifier (0xBEAC)
• the 16 bytes UUID
• the 2 byte major
• the 2 byte minor
• the 1 byte tx power

Byte 0-2: Standard BLE Flags

 Byte 0: Length :  0x02
 Byte 1: Type: 0x01 (Flags)
 Byte 2: Value: 0x06 (Typical Flags)

Byte 3-29: Apple Defined iBeacon Data

 Byte 3: Length: 0x1a
 Byte 4: Type: 0xff (Custom Manufacturer Packet)
 Byte 5-6: Manufacturer ID : 0x4c00 (Apple)
 Byte 7: SubType: 0x2 (iBeacon)
 Byte 8: SubType Length: 0x15
 Byte 9-24: Proximity UUID
 Byte 25-26: Major
 Byte 27-28: Minor
 Byte 29: Signal Power

ManufactureData : 设备厂商的自定义数据

使用addManufactureData(int manufacturerId, byte[] manufacturerSpecificData);

第一个参数0x004c，是厂商id，id长度为2个字节，不足2个字节系统会补0.

（比如id传入0xac, 不足两个字节，输入广播时：ac, 00)

 /**
      * create AdvertiseDate for iBeacon
      */
     public static AdvertiseData createIBeaconAdvertiseData(UUID proximityUuid, short major, short minor, byte txPower) {

         String[] uuidstr = proximityUuid.toString().replaceAll("-", "").toLowerCase().split("");
         byte[] uuidBytes = new byte[16];
         for (int i = 1, x = 0; i < uuidstr.length; x++) {
             uuidBytes[x] = (byte) ((Integer.parseInt(uuidstr[i++], 16) << 4) | Integer.parseInt(uuidstr[i++], 16));
         }
         byte[] majorBytes = {(byte) (major >> 8), (byte) (major & 0xff)};
         byte[] minorBytes = {(byte) (minor >> 8), (byte) (minor & 0xff)};
         byte[] mPowerBytes = {txPower};
         byte[] manufacturerData = new byte[0x17];
         byte[] flagibeacon = {0x02, 0x15};

         System.arraycopy(flagibeacon, 0x0, manufacturerData, 0x0, 0x2);
         System.arraycopy(uuidBytes, 0x0, manufacturerData, 0x2, 0x10);
         System.arraycopy(majorBytes, 0x0, manufacturerData, 0x12, 0x2);
         System.arraycopy(minorBytes, 0x0, manufacturerData, 0x14, 0x2);
         System.arraycopy(mPowerBytes, 0x0, manufacturerData, 0x16, 0x1);

         AdvertiseData.Builder builder = new AdvertiseData.Builder();
         builder.addManufacturerData(0x004c, manufacturerData);

         AdvertiseData adv = builder.build();
         return adv;
     }

6、创建广播设置：模式，是否可连接，功率

 setAdvertiseMode(int advertiseMode)
         设置广播的模式，低功耗，平衡和低延迟三种模式；
         对应  AdvertiseSettings.ADVERTISE_MODE_LOW_POWER  ,ADVERTISE_MODE_BALANCED ,ADVERTISE_MODE_LOW_LATENCY
         从左右到右，广播的间隔会越来越短 

 setConnectable(boolean connectable)
          设置是否可以连接。
          广播分为可连接广播和不可连接广播，一般不可连接广播应用在iBeacon设备上，这样APP无法连接上iBeacon设备

 setTimeout(int timeoutMillis)
          设置广播的最长时间，最大值为常量AdvertiseSettings.LIMITED_ADVERTISING_MAX_MILLIS = 180 * 1000;  180秒
          设为0时，代表无时间限制会一直广播

 setTxPowerLevel(int txPowerLevel)
          设置广播的信号强度
          常量有AdvertiseSettings.ADVERTISE_TX_POWER_ULTRA_LOW, ADVERTISE_TX_POWER_LOW, ADVERTISE_TX_POWER_MEDIUM, ADVERTISE_TX_POWER_HIGH
          从左到右分别表示强度越来越强.
          举例：当设置为ADVERTISE_TX_POWER_ULTRA_LOW时，
          手机1和手机2放在一起，手机2扫描到的rssi信号强度为-56左右，
          当设置为ADVERTISE_TX_POWER_HIGH  时， 扫描到的信号强度为-33左右，
          信号强度越大，表示手机和设备靠的越近

＊ AdvertiseSettings.ADVERTISE_TX_POWER_HIGH -56 dBm @ 1 meter with Nexus 5

＊ AdvertiseSettings.ADVERTISE_TX_POWER_LOW -75 dBm @ 1 meter with Nexus 5

＊ AdvertiseSettings.ADVERTISE_TX_POWER_MEDIUM -66 dBm @ 1 meter with Nexus 5

＊AdvertiseSettings.ADVERTISE_TX_POWER_ULTRA_LOW not detected with Nexus 5

 public AdvertiseSettings createAdvSettings(boolean connectable, int timeoutMillis) {
         AdvertiseSettings.Builder builder = new AdvertiseSettings.Builder();
         //设置广播的模式, 功耗相关
         builder.setAdvertiseMode(AdvertiseSettings.ADVERTISE_MODE_BALANCED);
         builder.setConnectable(connectable);
         builder.setTimeout(timeoutMillis);
         builder.setTxPowerLevel(AdvertiseSettings.ADVERTISE_TX_POWER_HIGH);
         AdvertiseSettings mAdvertiseSettings = builder.build();
         if (mAdvertiseSettings == null) {
             Log.e(TAG, "mAdvertiseSettings == null");
         }
         return mAdvertiseSettings;
     }

7、开始广播后的回调。提示广播开启是否成功。

 //发送广播的回调，onStartSuccess/onStartFailure很明显的两个Callback
     private AdvertiseCallback mAdvCallback = new AdvertiseCallback() {
         public void onStartSuccess(android.bluetooth.le.AdvertiseSettings settingsInEffect) {
             super.onStartSuccess(settingsInEffect);
             if (settingsInEffect != null) {
                 Log.d(TAG, "onStartSuccess TxPowerLv=" + settingsInEffect.getTxPowerLevel() + " mode=" + settingsInEffect.getMode() + " timeout=" + settingsInEffect.getTimeout());
             } else {
                 Log.d(TAG, "onStartSuccess, settingInEffect is null");
             }
         }

         public void onStartFailure(int errorCode) {
             super.onStartFailure(errorCode);
             Log.d(TAG, "onStartFailure errorCode=" + errorCode);

             if (errorCode == ADVERTISE_FAILED_DATA_TOO_LARGE) {
                 Toast.makeText(mContext, "advertise_failed_data_too_large", Toast.LENGTH_LONG).show();
                 Log.e(TAG, "Failed to start advertising as the advertise data to be broadcasted is larger than 31 bytes.");
             } else if (errorCode == ADVERTISE_FAILED_TOO_MANY_ADVERTISERS) {
                 Toast.makeText(mContext, "advertise_failed_too_many_advertises", Toast.LENGTH_LONG).show();
                 Log.e(TAG, "Failed to start advertising because no advertising instance is available.");

             } else if (errorCode == ADVERTISE_FAILED_ALREADY_STARTED) {
                 Toast.makeText(mContext, "advertise_failed_already_started", Toast.LENGTH_LONG).show();
                 Log.e(TAG, "Failed to start advertising as the advertising is already started");

             } else if (errorCode == ADVERTISE_FAILED_INTERNAL_ERROR) {
                 Toast.makeText(mContext, "advertise_failed_internal_error", Toast.LENGTH_LONG).show();
                 Log.e(TAG, "Operation failed due to an internal error");

             } else if (errorCode == ADVERTISE_FAILED_FEATURE_UNSUPPORTED) {
                 Toast.makeText(mContext, "advertise_failed_feature_unsupported", Toast.LENGTH_LONG).show();
                 Log.e(TAG, "This feature is not supported on this platform");

             }
         }
     };

注意：对于ios 设备接受广播，外围设备还是要广播出来一个16位的serviceUUID，因为扫描的时候要用（如果不指定特定服务的UUID，没有办法进行后台持续扫描连接）.

Android 上的低功耗蓝牙实践

源代码demo