Android 藍牙4.0(BLE) 理解--緊隨智能家居和可穿戴設備潮流

本文轉自:http://blog.csdn.net/chaoyue0071/article/details/43450183/

正文 :

本文簡單結合兩篇文章

http://blog.csdn.net/hellogv/article/details/24267685

http://blog.csdn.net/jimoduwu/article/details/21604215

在BLE協議中，有兩個角色，周邊（Periphery）和中央（Central），一箇中央可以同時連接多個周邊，但是一個周邊某一時刻只能連接一箇中央。但是不管是Periphery還是Central都是可以實現 GATT server 和 GATT client去傳輸數據，但是無法同時都是。

大概瞭解了概念後，看看Android BLE SDK的四個關鍵類（class）：

a) BluetoothGattServer作爲周邊來提供數據；BluetoothGattServerCallback返回周邊的狀態。

b) BluetoothGatt作爲中央來使用和處理數據；BluetoothGattCallback返回中央的狀態和周邊提供的數據。

因爲我們討論的是Android的BLE SDK，下面所有的BluetoothGattServer代表周邊，BluetoothGatt代表中央。

          

一.創建一個周邊（雖然目前周邊API在Android手機上不工作，但還是看看）

 a）先看看周邊用到的class，藍色橢圓

b）說明：

每一個周邊BluetoothGattServer，包含多個服務Service，每一個Service包含多個特徵Characteristic。

1.new一個特徵：character = new BluetoothGattCharacteristic(
UUID.fromString(characteristicUUID),
BluetoothGattCharacteristic.PROPERTY_NOTIFY,
BluetoothGattCharacteristic.PERMISSION_READ);

2.new一個服務：service = new BluetoothGattService(UUID.fromString(serviceUUID),
BluetoothGattService.SERVICE_TYPE_PRIMARY);

3.把特徵添加到服務：service.addCharacteristic(character);

4.獲取BluetoothManager：manager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);

5.獲取/打開周邊：BluetoothGattServer server = manager.openGattServer(this,
new BluetoothGattServerCallback(){...}); 

6.把service添加到周邊：server.addService(service);

7.開始廣播service：Google還沒有廣播Service的API，等吧！！！！！所以目前我們還不能讓一個Android手機作爲周邊來提供數據。

二.創建一箇中央（這次不會讓你失望，可以成功創建並且連接到周邊的）

a）先看看中央用到的class，藍色橢圓

b）說明：

爲了拿到中央BluetoothGatt，可要爬山涉水十八彎：

1.先拿到BluetoothManager：bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);

2.再拿到BluetoothAdapt：btAdapter = bluetoothManager.getAdapter();

3.開始掃描：btAdapter.startLeScan( BluetoothAdapter.LeScanCallback);

4.從LeScanCallback中得到BluetoothDevice：public void onLeScan(BluetoothDevice device, int rssi, byte[] scanRecord) {.....}

5.用BluetoothDevice得到BluetoothGatt：gatt = device.connectGatt(this, true, gattCallback);

終於拿到中央BluetoothGatt了，它有一堆方法（查API吧），調用這些方法，你就可以通過BluetoothGattCallback和周邊BluetoothGattServer交互了。

官方有給出BLE 通信的sample ，下面是牛人簡化了代碼，簡化得簡單明瞭

本文來自http://blog.csdn.net/hellogv/ ，引用必須註明出處！

最近穿戴設備發展得很火，把相關技術也帶旺了，其中一項是BLE（Bluetooth Low Energy）。BLE是藍牙4.0的核心Profile，主打功能是快速搜索，快速連接，超低功耗保持連接和傳輸數據，弱點是數據傳輸速率低，由於BLE的低功耗特點，因此普遍用於穿戴設備。Android 4.3纔開始支持BLE API，所以請各位客官把本文代碼運行在藍牙4.0和Android 4.3及其以上的系統，另外本文所用的BLE終端是一個藍牙4.0的串口藍牙模塊。

PS：我的i9100刷了4.4系統後，竟然也能跟BLE藍牙模塊通信。

BLE分爲三部分Service、Characteristic、Descriptor，這三部分都由UUID作爲唯一標示符。一個藍牙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終端交換數據的關鍵，Characteristic有較多的跟權限相關的字段，例如PERMISSION和PROPERTY，而其中最常用的是PROPERTY，本文所用的BLE藍牙模塊竟然沒有標準的Characteristic的PERMISSION。Characteristic的PROPERTY可以通過位運算符組合來設置讀寫屬性，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，獲取的BLE設備信息都通過Log，還有一些必要的讀寫藍牙方法，應該算是簡化到大家一看就可以懂了。本文代碼可以到http://download.csdn.net/detail/hellogv/7228819下載。接下來貼出本文運行的結果，首先是連接BLE設備後，枚舉出設備所有Service、Characteristic、Descriptor，並且手機會往Characteristic uuid=0000ffe1-0000-1000-8000-00805f9b34fb寫入“send data->”字符串，BLE終端收到數據通過串口傳到PC串口助手（見PC串口助手的截圖）：

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

這裏紅字是由BluetoothGattCallback的onCharacteristicRead()回調而打出Log

以下Log是PC上的串口工具通過BLE模塊發送過來，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;
    /**搜索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;
        }
        //開啓藍牙
        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終端數據交互的事件
        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();
    }

    /**
     * 搜索到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終端數據交互的事件
     */
    private BluetoothLeClass.OnDataAvailableListener mOnDataAvailable = new OnDataAvailableListener(){

        /**
         * BLE終端數據被讀的事件
         */
        @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終端寫入數據回調
         */
        @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的字段信息-----//
            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的字段信息-----//
            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是可以跟藍牙模塊串口通信的Characteristic
                if(gattCharacteristic.getUuid().toString().equals(UUID_KEY_DATA)){
                    //測試讀取當前Characteristic數據，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,收到藍牙模塊的數據後會觸發mOnDataAvailable.onCharacteristicWrite()
                    mBLE.setCharacteristicNotification(gattCharacteristic, true);
                    //設置數據內容
                    gattCharacteristic.setValue("send data->");
                    //往藍牙模塊寫入數據
                    mBLE.writeCharacteristic(gattCharacteristic);
                }

                //-----Descriptors的字段信息-----//
                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));
                    }
                 }
            }
        }//

    }
}