<uses-permission android:name="android.permission.BLUETOOTH"/> 使用藍(lán)牙所需要的權(quán)限
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/> 使用掃描和設(shè)置藍(lán)牙的權(quán)限（申明這一個(gè)權(quán)限必須申明上面一個(gè)權(quán)限）

    <!-- Needed only if your app targets Android 5.0 (API level 21) or higher. -->
    <uses-feature android:name="android.hardware.location.gps" />

    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

    <uses-feature android:name="android.hardware.bluetooth_le" android:required="true"/>

    // 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();
    }

    private BluetoothAdapter mBluetoothAdapter;
    ...
    // Initializes Bluetooth adapter.
    final BluetoothManager bluetoothManager =
            (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
    mBluetoothAdapter = bluetoothManager.getAdapter();

// Ensures Bluetooth is available on the device and it is enabled. If not,
// displays a dialog requesting user permission to enable Bluetooth.
if (mBluetoothAdapter == null || !mBluetoothAdapter.isEnabled()) {
    Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
    startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}

    // 打開(kāi)藍(lán)牙
    if (!mBluetoothAdapter.isEnabled()) {
        mBluetoothAdapter.enable();
    }

// 設(shè)備掃描回調(diào)
    private ScanCallback mScanCallback = new ScanCallback() {
        @Override
        public void onScanResult(int callbackType, final ScanResult result) {

            runOnUiThread(new Runnable() {
                @Override
                public void run() {

                    // 廣播的信息，可以在result中獲取
                    MDevice mDev = new MDevice(result.getDevice(), result.getRssi());
                    if (!mList.contains(mDev)) {
                        mList.add(mDev);
                    }
                    if (mList.size() > 0) {
                        mScanner.stopScan(mScanCallback);
                        Toast.makeText(MainActivity.this, "掃描結(jié)束，設(shè)備數(shù) " + mList.size()
                                , Toast.LENGTH_SHORT).show();
                    }
                }
            });
        }
    };

private BluetoothAdapter mBluetoothAdapter;
    private boolean mScanning;
    private Handler mHandler;

    // Stops scanning after 10 seconds.
    private static final long SCAN_PERIOD = 10000;
    ...
    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);
                }
            }, SCAN_PERIOD);

            mScanning = true;
            mBluetoothAdapter.startLeScan(mLeScanCallback);
        } else {
            mScanning = false;
            mBluetoothAdapter.stopLeScan(mLeScanCallback);
        }
        ...
    }

    startLeScan(UUID[], BluetoothAdapter.LeScanCallback)

    private void scanLeDevice() {

        //50秒后停止掃描
        mHander.postDelayed(stopScanRunnable, 50000);

        List<ScanFilter> filters = new ArrayList<>();
        ScanFilter filter = new ScanFilter.Builder()
                //"D8:B0:4C:E8:66:DC" 測(cè)試MAC 1
                //"D8:B0:4C:E2:45:2A"  測(cè)試MAC 2
                .setDeviceAddress("D8:B0:4C:E2:45:2A")
                .build();
        filters.add(filter);

        // 掃描
        mScanner.startScan(filters, new ScanSettings.Builder().setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY).build(), mScanCallback);

    }

boolean startLeScan(BluetoothAdapter.LeScanCallback callback)

public static BluetoothGatt mBluetoothGatt;

 mBluetoothGatt = device.connectGatt(context, false, mGattCallback);

    private final static BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
        @Override
        public void onConnectionStateChange(BluetoothGatt gatt, int status,
                                            int newState) {

            String intentAction;
            // GATT Server connected
            if (newState == BluetoothProfile.STATE_CONNECTED) {
                System.out.println("---------------------------->已經(jīng)連接");
                intentAction = ACTION_GATT_CONNECTED;
                mConnectionState = STATE_CONNECTED;
                broadcastConnectionUpdate(intentAction);
            }
            // GATT Server disconnected
            else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
                System.out.println("---------------------------->連接斷開(kāi)");
                intentAction = ACTION_GATT_DISCONNECTED;
                mConnectionState = STATE_DISCONNECTED;
                broadcastConnectionUpdate(intentAction);

            }
            // GATT Server disconnected
            else if (newState == BluetoothProfile.STATE_DISCONNECTING) {
                System.out.println("---------------------------->正在連接");
//                intentAction = ACTION_GATT_DISCONNECTING;
//                mConnectionState = STATE_DISCONNECTING;
//                broadcastConnectionUpdate(intentAction);
            }
        }
    }

mBluetoothGatt.discoverServices();

 @Override
        public void onServicesDiscovered(BluetoothGatt gatt, int status) {
            // GATT Services discovered
            //發(fā)現(xiàn)新的服務(wù)
            if (status == BluetoothGatt.GATT_SUCCESS) {
                System.out.println("---------------------------->發(fā)現(xiàn)服務(wù)");
                broadcastConnectionUpdate(ACTION_GATT_SERVICES_DISCOVERED);
            } 
        }

        //通過(guò) Descriptor 寫監(jiān)聽(tīng)
        @Override 
        public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor,
                                      int status) {

        }

        // 通過(guò) Descriptor 讀監(jiān)聽(tīng)
        @Override
        public void onDescriptorRead(BluetoothGatt gatt, BluetoothGattDescriptor descriptor,
                                     int status) {

        }


        @Override
        public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic
                characteristic, int status) {
            //write操作會(huì)調(diào)用此方法
            if (status == BluetoothGatt.GATT_SUCCESS) {
                System.out.println("onCharacteristicWrite ------------------->write success");
                Intent intent = new Intent(ACTION_GATT_CHARACTERISTIC_WRITE_SUCCESS);
                mContext.sendBroadcast(intent);
            } else {
                Intent intent = new Intent(ACTION_GATT_CHARACTERISTIC_ERROR);
                intent.putExtra(Constants.EXTRA_CHARACTERISTIC_ERROR_MESSAGE, "" + status);
                mContext.sendBroadcast(intent);
            }
        }

        @Override
        public void onCharacteristicRead(BluetoothGatt gatt,
                                         BluetoothGattCharacteristic characteristic, int status) {
            // 接收數(shù)據(jù)
        }

        @Override
        public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {

            //notify 會(huì)回調(diào)用此方法
            broadcastNotifyUpdate(characteristic);
        }

        @Override
        public void onMtuChanged(BluetoothGatt gatt, int mtu, int status) {
           super.onMtuChanged(gatt, mtu, status);

        }

void prepareBroadcastDataNotify(
            BluetoothGattCharacteristic characteristic) {

        final int charaProp = characteristic.getProperties();

        Toast.makeText(this, " " + charaProp, Toast.LENGTH_SHORT).show();

        if ((charaProp | BluetoothGattCharacteristic.PROPERTY_NOTIFY) > 0) {
            BluetoothLeService.setCharacteristicNotification(characteristic, true);
        }

    }

public static void setCharacteristicNotification(BluetoothGattCharacteristic characteristic, boolean enabled) {

        if (mBluetoothAdapter == null || mBluetoothGatt == null) {
            return;
        }
        //通知遠(yuǎn)程端開(kāi)啟 notify 
        if (characteristic.getDescriptor(UUID.fromString(GattAttributes.CLIENT_CHARACTERISTIC_CONFIG)) != null) {
            if (enabled == true) {
                BluetoothGattDescriptor descriptor = characteristic
                        .getDescriptor(UUID.fromString(GattAttributes.CLIENT_CHARACTERISTIC_CONFIG));
                descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
                mBluetoothGatt.writeDescriptor(descriptor);
            } else {
                BluetoothGattDescriptor descriptor = characteristic
                        .getDescriptor(UUID.fromString(GattAttributes.CLIENT_CHARACTERISTIC_CONFIG));
                descriptor.setValue(BluetoothGattDescriptor.DISABLE_NOTIFICATION_VALUE);
                mBluetoothGatt.writeDescriptor(descriptor);
            }
        }
        mBluetoothGatt.setCharacteristicNotification(characteristic, enabled);
    }

public static void writeCharacteristicGattDb(
            BluetoothGattCharacteristic characteristic, byte[] byteArray) {

        if (mBluetoothAdapter == null || mBluetoothGatt == null) {
            return;
        } else {
            byte[] valueByte = byteArray;
            characteristic.setValue(valueByte);
            mBluetoothGatt.writeCharacteristic(characteristic);
        }
    }

 @Override
        public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic
                characteristic, int status) {
            //write操作會(huì)調(diào)用此方法
            if (status == BluetoothGatt.GATT_SUCCESS) {
                System.out.println("onCharacteristicWrite ------------------->write success");
                Intent intent = new Intent(ACTION_GATT_CHARACTERISTIC_WRITE_SUCCESS);
                // 這里通過(guò)屬性能夠讀取你發(fā)送的數(shù)據(jù)，可以對(duì)此數(shù)據(jù)進(jìn)行判斷
                characteristic.getValue();
                mContext.sendBroadcast(intent);
            } else {
                Intent intent = new Intent(ACTION_GATT_CHARACTERISTIC_ERROR);
                intent.putExtra(Constants.EXTRA_CHARACTERISTIC_ERROR_MESSAGE, "" + status);
                mContext.sendBroadcast(intent);
            }
        }