Android提高之Android手機與BLE終端通訊_Android

最近穿戴裝置發展得很火，把相關技術也帶旺了，其中一項是BLE（Bluetooth Low Energy）。BLE是藍芽4.0的核心Profile，主打功能是快速搜尋，快速串連，超低功耗保持串連和傳輸資料，弱點是資料轉送速率低，由於BLE的低功耗特點，因此普遍用於穿戴裝置。Android 4.3才開始支援BLE API，所以請各位客官把本文代碼運行在藍芽4.0和Android 4.3及其以上的系統，另外本文所用的BLE終端是一個藍芽4.0的串口藍芽模組。

註：筆者的i9100刷了4.4系統後，竟然也能跟BLE藍芽模組通訊。

BLE分為三部分Service、Characteristic、Descriptor，這三部分都由UUID作為唯一標示符。一個藍芽4.0的終端可以包含多個Service，一個Service可以包含多個Characteristic，一個Characteristic包含一個Value和多個Descriptor，一個Descriptor包含一個Value。一般來說，Characteristic是手機與BLE終端交換資料的關鍵，Characteristic有較多的跟許可權相關的欄位，例如PERMISSION和PROPERTY，而其中最常用的是PROPERTY，本文所用的BLE藍芽模組竟然沒有標準的Characteristic的PERMISSION。Characteristic的PROPERTY可以通過位元運算符組合來設定讀寫屬性，例如READ|WRITE、READ|WRITE_NO_RESPONSE|NOTIFY，因此讀取PROPERTY後要分解成所用的組合（本文代碼已含此分解方法）。

本文代碼改自Android 4.3 Sample的BluetoothLeGatt，把冗餘代碼去掉，擷取的BLE裝置資訊都通過Log，還有一些必要的讀寫藍芽方法，應該算是簡化到大家一看就可以懂了。本文完整代碼可以點擊此處本站下載。

接下來貼出本文啟動並執行結果，首先是串連BLE裝置後，枚舉出裝置所有Service、Characteristic、Descriptor，並且手機會往Characteristic uuid=0000ffe1-0000-1000-8000-00805f9b34fb寫入“send data->”字串，BLE終端收到資料通過串口傳到PC串口助手：
04-21 18:28:25.465: E/DeviceScanActivity(12254): -->service type:PRIMARY
04-21 18:28:25.465: E/DeviceScanActivity(12254): -->includedServices size:0
04-21 18:28:25.465: E/DeviceScanActivity(12254): -->service uuid:00001800-0000-1000-8000-00805f9b34fb
04-21 18:28:25.465: E/DeviceScanActivity(12254): ---->char uuid:00002a00-0000-1000-8000-00805f9b34fb
04-21 18:28:25.465: E/DeviceScanActivity(12254): ---->char permission:UNKNOW
04-21 18:28:25.465: E/DeviceScanActivity(12254): ---->char property:READ
04-21 18:28:25.465: E/DeviceScanActivity(12254): ---->char uuid:00002a01-0000-1000-8000-00805f9b34fb
04-21 18:28:25.470: E/DeviceScanActivity(12254): ---->char permission:UNKNOW
04-21 18:28:25.470: E/DeviceScanActivity(12254): ---->char property:READ
04-21 18:28:25.470: E/DeviceScanActivity(12254): ---->char uuid:00002a02-0000-1000-8000-00805f9b34fb
04-21 18:28:25.470: E/DeviceScanActivity(12254): ---->char permission:UNKNOW
04-21 18:28:25.470: E/DeviceScanActivity(12254): ---->char property:READ|WRITE|
04-21 18:28:25.470: E/DeviceScanActivity(12254): ---->char uuid:00002a03-0000-1000-8000-00805f9b34fb
04-21 18:28:25.470: E/DeviceScanActivity(12254): ---->char permission:UNKNOW
04-21 18:28:25.475: E/DeviceScanActivity(12254): ---->char property:READ|WRITE|
04-21 18:28:25.475: E/DeviceScanActivity(12254): ---->char uuid:00002a04-0000-1000-8000-00805f9b34fb
04-21 18:28:25.475: E/DeviceScanActivity(12254): ---->char permission:UNKNOW
04-21 18:28:25.475: E/DeviceScanActivity(12254): ---->char property:READ
04-21 18:28:25.475: E/DeviceScanActivity(12254): -->service type:PRIMARY
04-21 18:28:25.475: E/DeviceScanActivity(12254): -->includedServices size:0
04-21 18:28:25.475: E/DeviceScanActivity(12254): -->service uuid:00001801-0000-1000-8000-00805f9b34fb
04-21 18:28:25.480: E/DeviceScanActivity(12254): ---->char uuid:00002a05-0000-1000-8000-00805f9b34fb
04-21 18:28:25.480: E/DeviceScanActivity(12254): ---->char permission:UNKNOW
04-21 18:28:25.480: E/DeviceScanActivity(12254): ---->char property:INDICATE
04-21 18:28:25.480: E/DeviceScanActivity(12254): -------->desc uuid:00002902-0000-1000-8000-00805f9b34fb
04-21 18:28:25.480: E/DeviceScanActivity(12254): -------->desc permission:UNKNOW
04-21 18:28:25.480: E/DeviceScanActivity(12254): -->service type:PRIMARY
04-21 18:28:25.480: E/DeviceScanActivity(12254): -->includedServices size:0
04-21 18:28:25.480: E/DeviceScanActivity(12254): -->service uuid:0000ffe0-0000-1000-8000-00805f9b34fb
04-21 18:28:25.480: E/DeviceScanActivity(12254): ---->char uuid:0000ffe1-0000-1000-8000-00805f9b34fb
04-21 18:28:25.480: E/DeviceScanActivity(12254): ---->char permission:UNKNOW
04-21 18:28:25.480: E/DeviceScanActivity(12254): ---->char property:READ|WRITE_NO_RESPONSE|NOTIFY|
04-21 18:28:25.490: E/DeviceScanActivity(12254): -------->desc uuid:00002902-0000-1000-8000-00805f9b34fb
04-21 18:28:25.490: E/DeviceScanActivity(12254): -------->desc permission:UNKNOW
04-21 18:28:25.490: E/DeviceScanActivity(12254): -------->desc uuid:00002901-0000-1000-8000-00805f9b34fb
04-21 18:28:25.490: E/DeviceScanActivity(12254): -------->desc permission:UNKNOW
04-21 18:28:26.025: E/DeviceScanActivity(12254): onCharRead BLE DEVICE read 0000ffe1-0000-1000-8000-00805f9b34fb -> 00
這裡紅字是由BluetoothGattCallback的onCharacteristicRead()回調而打出Log

以下Log是PC上的串口工具通過BLE模組發送過來，由BluetoothGattCallback的 onCharacteristicChanged（）打出Log
04-21 18:30:18.260: E/DeviceScanActivity(12254): onCharWrite BLE DEVICE write 0000ffe1-0000-1000-8000-00805f9b34fb -> send data to phone
04-21 18:30:18.745: E/DeviceScanActivity(12254): onCharWrite BLE DEVICE write 0000ffe1-0000-1000-8000-00805f9b34fb -> send data to phone
04-21 18:30:19.085: E/DeviceScanActivity(12254): onCharWrite BLE DEVICE write 0000ffe1-0000-1000-8000-00805f9b34fb -> send data to phone
04-21 18:30:19.350: E/DeviceScanActivity(12254): onCharWrite BLE DEVICE write 0000ffe1-0000-1000-8000-00805f9b34fb -> send data to phone
04-21 18:30:19.605: E/DeviceScanActivity(12254): onCharWrite BLE DEVICE write 0000ffe1-0000-1000-8000-00805f9b34fb -> send data to phone
04-21 18:30:19.835: E/DeviceScanActivity(12254): onCharWrite BLE DEVICE write 0000ffe1-0000-1000-8000-00805f9b34fb -> send data to phone
04-21 18:30:20.055: E/DeviceScanActivity(12254): onCharWrite BLE DEVICE write 0000ffe1-0000-1000-8000-00805f9b34fb -> send data to phone
04-21 18:30:20.320: E/DeviceScanActivity(12254): onCharWrite BLE DEVICE write 0000ffe1-0000-1000-8000-00805f9b34fb -> send data to phone
04-21 18:30:20.510: E/DeviceScanActivity(12254): onCharWrite BLE DEVICE write 0000ffe1-0000-1000-8000-00805f9b34fb -> send data to phone
04-21 18:30:20.735: E/DeviceScanActivity(12254): onCharWrite BLE DEVICE write 0000ffe1-0000-1000-8000-00805f9b34fb -> send data to phone
04-21 18:30:21.000: E/DeviceScanActivity(12254): onCharWrite BLE DEVICE write 0000ffe1-0000-1000-8000-00805f9b34fb -> send data to phone

接下來貼出本文核心代碼：

public class DeviceScanActivity extends ListActivity { private final static String TAG = DeviceScanActivity.class.getSimpleName(); private final static String UUID_KEY_DATA = "0000ffe1-0000-1000-8000-00805f9b34fb";  private LeDeviceListAdapter mLeDeviceListAdapter;  /**搜尋BLE終端*/  private BluetoothAdapter mBluetoothAdapter;  /**讀寫BLE終端*/  private BluetoothLeClass mBLE;  private boolean mScanning;  private Handler mHandler;  // Stops scanning after 10 seconds.  private static final long SCAN_PERIOD = 10000;  @Override  public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    getActionBar().setTitle(R.string.title_devices);    mHandler = new Handler();    // Use this check to determine whether BLE is supported on the device. Then you can    // selectively disable BLE-related features.    if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {      Toast.makeText(this, R.string.ble_not_supported, Toast.LENGTH_SHORT).show();      finish();    }    // Initializes a Bluetooth adapter. For API level 18 and above, get a reference to    // BluetoothAdapter through BluetoothManager.    final BluetoothManager bluetoothManager =        (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);    mBluetoothAdapter = bluetoothManager.getAdapter();    // Checks if Bluetooth is supported on the device.    if (mBluetoothAdapter == null) {      Toast.makeText(this, R.string.error_bluetooth_not_supported, Toast.LENGTH_SHORT).show();      finish();      return;    }    //開啟藍芽    mBluetoothAdapter.enable();    mBLE = new BluetoothLeClass(this);    if (!mBLE.initialize()) {      Log.e(TAG, "Unable to initialize Bluetooth");      finish();    }    //發現BLE終端的Service時回調    mBLE.setOnServiceDiscoverListener(mOnServiceDiscover);    //收到BLE終端資料互動的事件    mBLE.setOnDataAvailableListener(mOnDataAvailable);  }  @Override  protected void onResume() {    super.onResume();    // Initializes list view adapter.    mLeDeviceListAdapter = new LeDeviceListAdapter(this);    setListAdapter(mLeDeviceListAdapter);    scanLeDevice(true);  }  @Override  protected void onPause() {    super.onPause();    scanLeDevice(false);    mLeDeviceListAdapter.clear();    mBLE.disconnect();  }  @Override  protected void onStop() {    super.onStop();    mBLE.close();  }  @Override  protected void onListItemClick(ListView l, View v, int position, long id) {    final BluetoothDevice device = mLeDeviceListAdapter.getDevice(position);    if (device == null) return;    if (mScanning) {      mBluetoothAdapter.stopLeScan(mLeScanCallback);      mScanning = false;    }    mBLE.connect(device.getAddress());  }  private void scanLeDevice(final boolean enable) {    if (enable) {      // Stops scanning after a pre-defined scan period.      mHandler.postDelayed(new Runnable() {        @Override        public void run() {          mScanning = false;          mBluetoothAdapter.stopLeScan(mLeScanCallback);          invalidateOptionsMenu();        }      }, SCAN_PERIOD);      mScanning = true;      mBluetoothAdapter.startLeScan(mLeScanCallback);    } else {      mScanning = false;      mBluetoothAdapter.stopLeScan(mLeScanCallback);    }    invalidateOptionsMenu();  }  /**   * 搜尋到BLE終端服務的事件   */  private BluetoothLeClass.OnServiceDiscoverListener mOnServiceDiscover = new OnServiceDiscoverListener(){ @Override public void onServiceDiscover(BluetoothGatt gatt) {  displayGattServices(mBLE.getSupportedGattServices()); }  };  /**   * 收到BLE終端資料互動的事件   */  private BluetoothLeClass.OnDataAvailableListener mOnDataAvailable = new OnDataAvailableListener(){   /**   * BLE終端資料被讀的事件   */ @Override public void onCharacteristicRead(BluetoothGatt gatt,  BluetoothGattCharacteristic characteristic, int status) {  if (status == BluetoothGatt.GATT_SUCCESS)   Log.e(TAG,"onCharRead "+gatt.getDevice().getName()   +" read "   +characteristic.getUuid().toString()   +" -> "   +Utils.bytesToHexString(characteristic.getValue())); }   /**   * 收到BLE終端寫入資料回調   */ @Override public void onCharacteristicWrite(BluetoothGatt gatt,  BluetoothGattCharacteristic characteristic) {  Log.e(TAG,"onCharWrite "+gatt.getDevice().getName()   +" write "   +characteristic.getUuid().toString()   +" -> "   +new String(characteristic.getValue())); }  };  // Device scan callback.  private BluetoothAdapter.LeScanCallback mLeScanCallback =      new BluetoothAdapter.LeScanCallback() {    @Override    public void onLeScan(final BluetoothDevice device, int rssi, byte[] scanRecord) {      runOnUiThread(new Runnable() {        @Override        public void run() {          mLeDeviceListAdapter.addDevice(device);          mLeDeviceListAdapter.notifyDataSetChanged();        }      });    }  };  private void displayGattServices(List<BluetoothGattService> gattServices) {    if (gattServices == null) return;    for (BluetoothGattService gattService : gattServices) {     //-----Service的欄位資訊-----//     int type = gattService.getType();      Log.e(TAG,"-->service type:"+Utils.getServiceType(type));      Log.e(TAG,"-->includedServices size:"+gattService.getIncludedServices().size());      Log.e(TAG,"-->service uuid:"+gattService.getUuid());            //-----Characteristics的欄位資訊-----//      List<BluetoothGattCharacteristic> gattCharacteristics =gattService.getCharacteristics();      for (final BluetoothGattCharacteristic gattCharacteristic: gattCharacteristics) {        Log.e(TAG,"---->char uuid:"+gattCharacteristic.getUuid());        int permission = gattCharacteristic.getPermissions();        Log.e(TAG,"---->char permission:"+Utils.getCharPermission(permission));        int property = gattCharacteristic.getProperties();        Log.e(TAG,"---->char property:"+Utils.getCharPropertie(property));        byte[] data = gattCharacteristic.getValue();     if (data != null && data.length > 0) {      Log.e(TAG,"---->char value:"+new String(data));     }     //UUID_KEY_DATA是可以跟藍芽模組串口通訊的Characteristic     if(gattCharacteristic.getUuid().toString().equals(UUID_KEY_DATA)){            //測試讀取當前Characteristic資料，會觸發mOnDataAvailable.onCharacteristicRead()      mHandler.postDelayed(new Runnable() {            @Override            public void run() {             mBLE.readCharacteristic(gattCharacteristic);            }          }, 500);      //接受Characteristic被寫的通知,收到藍芽模組的資料後會觸發mOnDataAvailable.onCharacteristicWrite()      mBLE.setCharacteristicNotification(gattCharacteristic, true);      //設定資料內容      gattCharacteristic.setValue("send data->");      //往藍芽模組寫入資料      mBLE.writeCharacteristic(gattCharacteristic);     }     //-----Descriptors的欄位資訊-----//  List<BluetoothGattDescriptor> gattDescriptors = gattCharacteristic.getDescriptors();  for (BluetoothGattDescriptor gattDescriptor : gattDescriptors) {   Log.e(TAG, "-------->desc uuid:" + gattDescriptor.getUuid());   int descPermission = gattDescriptor.getPermissions();   Log.e(TAG,"-------->desc permission:"+ Utils.getDescPermission(descPermission));   byte[] desData = gattDescriptor.getValue();   if (desData != null && desData.length > 0) {   Log.e(TAG, "-------->desc value:"+ new String(desData));   }      }      }    }//  }}

感興趣的讀者可以動手測試一下代碼的運行情況，希望能對大家的Android項目開發有所協助。