前言
本文主要讲解经典蓝牙和BLE(低功耗蓝牙)的使用流程
一.获取蓝牙适配器
BluetoothAdapter 为蓝牙适配器,所有对蓝牙的操作都是通过它完成的.
BluetoothManager bluetoothManager =(BluetoothManager)getSystemService(Context.BLUETOOTH_SERVICE);
BluetoothAdapter mAdapter = bluetoothManager.getAdapter();
或者
BluetoothAdapter mAdapter = BluetoothAdapter.getDefaultAdapter();
以上两种实际一样.
二.开启蓝牙
友好界面的开启,在onActivityResult中获取开启结果
if (!mAdapter.isEnabled()){//先判断是否已开启
Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(intent,REQUEST_CODE);
}
简单粗暴的开启,当然这个也是异步开启的.
if (!mAdapter.isEnabled()){//先判断是否已开启
mAdapter.enable();
}
由于上面是该方式为异步开启,如果想监听则要注册广播,如下
//注册广播
private void registerBluetoothReceiver() {
IntentFilter filter = new IntentFilter();
filter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);//蓝牙状态改变的广播
filter.addAction(BluetoothDevice.ACTION_FOUND);//找到设备的广播
filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);//搜索完成的广播
filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);//开始扫描的广播
filter.addAction(BluetoothDevice.ACTION_BOND_STATE_CHANGED);//状态改变
registerReceiver(mReceive, intentFilter);
}
//注销广播
private void unregisterBluetoothReceiver() {
if (mReceive != null) {
unregisterReceiver(mReceive);
mReceive = null;
}
}
private BroadcastReceiver mReceive = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (action == null) {
return;
}
switch (action) {
case BluetoothAdapter.ACTION_STATE_CHANGED:
int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, -1);
if(BluetoothAdapter.STATE_OFF == state) {
//蓝牙关闭
}else if(BluetoothAdapter.STATE_ON == state) {
//蓝牙开启,开始扫描蓝牙
}
break;
case BluetoothDevice.ACTION_ACL_CONNECTED:
break;
case BluetoothDevice.ACTION_BOND_STATE_CHANGED:
//绑定状态返回
break;
case BluetoothDevice.ACTION_FOUND:
//扫描到的设备
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
break;
}
}
};
三.扫描蓝牙
金典蓝牙和BLE蓝牙扫描方试上有区别了.
1.经典蓝牙扫描
经典蓝牙获取到的设备需要到上面注册的广播中获取.
if (mAdapter.isDiscovering()){
mAdapter.cancelDiscovery();
}
mAdapter.startDiscovery();
2.BLE蓝牙扫描
BLE扫描到的蓝牙直接回调得到设备
public void startScanDevice() {
BluetoothLeScanner bluetoothLeScanner = mAdapter.getBluetoothLeScanner();
bluetoothLeScanner.startScan(mLocalScanCallback);
}
ScanCallback mLocalScanCallback = new ScanCallback() {
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
@Override
public void onScanResult(int callbackType, ScanResult result) {
BluetoothDevice device = result.getDevice();
//扫描到的设备
}
@Override
public void onScanFailed(int errorCode) {
}
};
四.连接蓝牙
获取扫描到的BluetoothDevice(蓝牙设备)后即可连接.
1.经典蓝牙
配对
该方法为异步调用,返回true为正在绑定,同样需要在上面注册的广播中获取结果
boolean bond = device.createBond();
连接
客户端
连接操作为耗时过程,应该到子线程中进行,代码中的uuid可以理解为http中的端口号,这是一个唯一标识.
if (mAdapter.isDiscovering()) {
mAdapter.cancelDiscovery();
}
ParcelUuid parcelUuid = device.getUuids()[0];
BluetoothSocket mBluetoothSocket = device.createRfcommSocketToServiceRecord(parcelUuid.getUuid());
if (!mBluetoothSocket.isConnected()) {
mBluetoothSocket.connect();
}
服务端
/**
* 开启服务端
*/
public void startBluetoothService() {
while (true) {
try {
BluetoothServerSocket bluetoothServerSocket = mAdapter.listenUsingRfcommWithServiceRecord("zcx", UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"));
BluetoothSocket bluetoothSocket = bluetoothServerSocket.accept();
if (bluetoothSocket != null) {
bluetoothServerSocket .close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
2.BLE蓝牙
//连接蓝牙
bluetoothGatt = device.connectGatt(getApplicationContext(), false, new BluetoothGattCallback() {
@ThreadChange
@Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
//发现服务
bluetoothGatt.discoverServices();
if (newState == BluetoothProfile.STATE_CONNECTED) {
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
} else if (newState == BluetoothProfile.STATE_CONNECTING) {
} else if (newState == BluetoothProfile.STATE_DISCONNECTING) {
}
}
@Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
super.onServicesDiscovered(gatt, status);
BluetoothGattService service = bluetoothGatt.getService(UUID.fromString(SERVICE_UUID));
BluetoothGattCharacteristic characteristic = service.getCharacteristic(UUID.fromString(Characteristic_uuid));
//设置接收通知
bluetoothGatt.setCharacteristicNotification(characteristic, true);
//00002902-0000-1000-8000-00805f9b34fb为系统接受通知自带的UUID
BluetoothGattDescriptor dsc = characteristic.getDescriptor(UUID.fromString("00002902-0000-1000-8000-00805f9b34fb"));
dsc.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
//设置BluetoothGattDescriptor 使蓝牙设备发送通知信号时回调onCharacteristicChanged方法
boolean success = bluetoothGatt.writeDescriptor(dsc);
Log.d(TAG, "writing enabledescriptor:" + success);
}
@Override
public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
}
@Override
public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
super.onCharacteristicWrite(gatt, characteristic, status);
}
@Override
public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
//接收到的通知
}
});
break;
}
四.通讯
1.经典蓝牙
//接收消息,需要用个子线程
public void receiveMessage(){
if (bluetoothSocket == null){
return;
}
try {
InputStream inputStream = bluetoothSocket.getInputStream();
BufferedReader bff = new BufferedReader(new InputStreamReader(inputStream));
String message;
while (true) {
while ((message= bff.readLine()) != null) {
//获取到的数据
}
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
//发送文本消息
public static void sendMessage(String message) {
if (bluetoothSocket == null || TextUtils.isEmpty(message)){
return;
}
try {
message += "\r\n";
OutputStream outputStream = bluetoothSocket.getOutputStream();
outputStream.write(message.getBytes("utf-8"));
outputStream.flush();
} catch (IOException e) {
e.printStackTrace();
}
2.BLE蓝牙
ble接收消息在连接时的onCharacteristicChanged方法中可以接收到,这里需要发送的方法
//发送文本消息
public boolean sendMessage(String message) {
if (bluetoothGatt == null) return false;
BluetoothGattCharacteristic gc = bluetoothGatt.getService(UUID.fromString(SERVICE_UUID)).getCharacteristic(UUID.fromString(Characteristic_uuid));
gc.setValue(message.getBytes());
bluetoothGatt.writeCharacteristic(gc);
return true;
}
android蓝牙到这里就结束了,可以愉快的使用蓝牙了
总结
这里总结一下这两种蓝牙区别吧
金典蓝牙: 3.0版本以下的蓝牙，功耗高、传输数据量大、传输距离只有10米。
BLE(低功耗)蓝牙 4.0及以上版本的蓝牙，低功耗、数据量小、距离50米左右。