Android蓝牙BLE应用的开发

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1、检查设备是否支持蓝牙设备：

if(!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {    Toast.makeText(this,"不支持BLE功能",Toast.LENGTH_SHORT).show();    finish();}else {    Toast.makeText(this,"支持BLE功能",Toast.LENGTH_SHORT).show();}

2、获取本机的蓝牙适配器：

mBleAdapter = BluetoothAdapter.getDefaultAdapter();

3、打开蓝牙设备：

if(mBleAdapter != null || !mBleAdapter.isEnable())

{

Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);

startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);

}

mBleAdapter .enable(); //打开；

mBleAdapter .disable(); //关闭；

4、注册事件的广播并开始扫描周末设备:

//开始扫描设备public void  startDiscoveryDevice(){    IntentFilter    filter = new IntentFilter();    filter.addAction(BluetoothDevice.ACTION_FOUND);    filter.addAction(BluetoothDevice.ACTION_BOND_STATE_CHANGED);    filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);    filter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);    blueContext.registerReceiver(blueEventRecv, filter);   //注册要接收的广播消息    if(bluetoothAdapter.isDiscovering() == false)        bluetoothAdapter.startDiscovery()}//停止扫描设备public void stopDiscoveryDevice(){    if(bluetoothAdapter.isDiscovering() )        bluetoothAdapter.cancelDiscovery();}

5、配对以及连接周边蓝牙设备： 4.0和2.0的区别在此处4.0的直接连接，4.0似乎不需要进行配对。

首先声明一个回调，供GATT上各种事件产生变化时调用：

private BluetoothGattCallback   bluetoothGattCallBack=new BluetoothGattCallback() {
    @Override
    public voidonConnectionStateChange(BluetoothGatt gatt,intstatus, intnewState) {
        super.onConnectionStateChange(gatt, status, newState);
        if(newState == BluetoothGatt.STATE_CONNECTED) {
            Log.d(TAG,"onConnectionStateChange: 连接成功 ->"+bluetoothGatt.discoverServices());
        }
    }
    @Override
    public voidonServicesDiscovered(BluetoothGatt gatt,intstatus) {
        super.onServicesDiscovered(gatt, status);

        if(status == BluetoothGatt.GATT_SUCCESS){
            List<BluetoothGattService> services = bluetoothGatt.getServices();
            Log.d(TAG,"onServicesDiscovered: 共有"+ services.size());
            for(inti=0;i< services.size();i++) {
                Log.e(TAG,"onServicesDiscovered: 服务 UUID ="+ services.get(i).getUuid() );
                List<BluetoothGattCharacteristic>   listGattChar = services.get(i).getCharacteristics();
                for(intj=0; j < listGattChar.size(); j++){
                    Log.e(TAG,"onServicesDiscovered: --特征 UUID="+listGattChar.get(j).getUuid() );
                }
            }
            BluetoothGattService service = bluetoothGatt.getService(UUID.fromString(HC_UUID_SERV));
            if(service !=null) {
                bluetoothCharacter = service.getCharacteristic(UUID.fromString(HC_UUID_CHAR));
                bluetoothGatt.readCharacteristic(bluetoothCharacter);
                Log.e(TAG,"onServicesDiscovered: 获取特征值成功");
            }
            else
                Log.e(TAG,"onServicesDiscovered: 获取特征值失败");
        }
        else{
            Log.e(TAG,"onServicesDiscovered: 收到事件状态"+ status );
        }
    }

    @Override
    public voidonCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic,intstatus) {
        super.onCharacteristicWrite(gatt, characteristic, status);
        if(status == BluetoothGatt.GATT_SUCCESS){
            Log.d(TAG,"onCharacteristicWrite: 写数据成功 ->"+newString(characteristic.getValue()));
        }
        else{
            Log.d(TAG,"onCharacteristicWrite: 写数据失败"+ status);
        }
    }

    @Override
    public voidonCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
        super.onCharacteristicChanged(gatt, characteristic);
        byte[] buffer = characteristic.getValue();
        String string = new String(buffer);
        Log.d(TAG,"onCharacteristicChanged: "+string);
        callBackForState.onDataReceived(string);
    }

    @Override
    public voidonCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic,intstatus) {
        super.onCharacteristicRead(gatt, characteristic, status);

        if(status == BluetoothGatt.GATT_SUCCESS){
            byte[]     buffer = characteristic.getValue();
            if(buffer.length>1) {
                String str = new String(buffer);
                Log.d(TAG,"onCharacteristicRead: "+ gatt.getDevice().getName()+"："+characteristic.getUuid().toString());
                Log.d(TAG,"onCharacteristicRead: 读数据成功:"+ str);
                bluetoothGatt.readCharacteristic(bluetoothCharacter);
            }
            System.out.println(newString(buffer));
        }
        else{
            Log.d(TAG,"onCharacteristicRead: 写数据失败:"+ status);
        }
    }
    @Override
    public voidonDescriptorRead(BluetoothGatt gatt, BluetoothGattDescriptor descriptor,intstatus) {
        super.onDescriptorRead(gatt, descriptor, status);
        byte[] desc = descriptor.getValue();
        if (desc != null) {
            Log.w(TAG,"----onDescriptorRead value: 读取描述 ->"+ new String(desc));
        }
    }
};

然后配对蓝牙设备：由于是BLE所以要使用GATT。主要是使用connectGatt获得BluetoothGatt对象，然后通过BluetoothGatt对象连建立连接。

public void bondBlueDevice(BluetoothDevice device)
{
    if (device != null) {
        bluetoothGatt = device.connectGatt(blueContext,true,bluetoothGattCallBack);
        bluetoothGatt.connect();
    }
    else{
        Log.d(TAG,"bondBlueDevice: 配对失败,设备为空");
    }
}

7、发送数据到远端设备

发送和接收都是使用蓝牙的Characteristic进行中转处理的即不是由特性直接进行发送的。而是将值设置进bluetoothCharacter中，在有bluetoothGatt将特性给发送出去。

public boolean sendTest()
{
    if(bluetoothCharacter!=null){
        bluetoothGatt.setCharacteristicNotification(bluetoothCharacter,true);
        bluetoothCharacter.setValue("hello world".getBytes());
        bluetoothCharacter.setWriteType(BluetoothGattCharacteristic.WRITE_TYPE_NO_RESPONSE);
        bluetoothGatt.writeCharacteristic(bluetoothCharacter);
        return true;
    }
    else {
        Log.d(TAG,"sendTest:blueCharacter为空");
        return false;
    }
}

8、接收远端蓝牙数据：

BLE的接收数据是在之前我们在配对时所注册进去的回调onCharacteristicChanged()中处理的,这里要加一句坑爹的函数名，一直以为是onCharacteristicRead中来处理所接收的数据的。为了这个折腾了很久。结果在一个博客中，无意看到了一句话(由BluetoothGattCallback的onCharacteristicChanged打印的数据)，才恍然大悟。

    public voidonCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
        super.onCharacteristicChanged(gatt, characteristic);
        byte[] buffer = characteristic.getValue();
        String string = new String(buffer);
        Log.d(TAG,"onCharacteristicChanged: "+string);
        callBackForState.onDataReceived(string);
    }

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