Android 蓝牙开发

风澜松叶 發表於 2021-10-26 10:16:00

<h2>Android 蓝牙开发</h2>
我们在进行蓝牙开发时首先要了解低功耗蓝牙、经典蓝牙、单模蓝牙、双模蓝牙之间的关系。 单模蓝牙：支持低功耗蓝牙 双模蓝牙：支持低功耗蓝牙和经典蓝牙 经典蓝牙：支持经典蓝牙 蓝牙开发大致分为这几步 
前面需要定位权限和蓝牙权限的支持
发现设备：
经典蓝牙发现设备api BluetoothAdapter.startDiscovery 听说可以同时发现经典蓝牙和低功耗蓝牙(BLE)。但我这没单模的蓝牙，所以没办法测试。 因为startDiscovery返回的是一个是否开始扫描设备，我们要获取蓝牙设备的信息需要注册一个 BroadcastReceiver 针对 ACTION_FOUND  Intent 会携带额外的字段 EXTRA_DEVICE 和 EXTRA_CLASS。这两者分别包含 BluetoothDevice 和 BluetoothClass。
<div class="cnblogs_code">
<pre>var filter =IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mReceiver,filter);

val mReceiver = object :BroadcastReceiver(){
 override fun onReceive(context: Context?, intent: Intent?) {
 var action = intent?.action
 if(BluetoothDevice.ACTION_FOUND == action){
 var device = intent?.getParcelableExtra<BluetoothDevice>(BluetoothDevice.EXTRA_DEVICE)
 }
 }

}
override fun onDestroy() {
 super.onDestroy()
 unregisterReceiver(mReceiver)
} </pre>
</div>
Ble发现设备api BluetoothAdapter.getBluetoothLeScanner() BluetoothLeScanner.startScan(ScanCallback callback)//扫描会在屏幕关闭时停止以节省电量。再次打开屏幕时，将恢复扫描。为避免这种情况，请使用下面两个 BluetoothLeScanner.startScan(List<ScanFilter> filters, ScanSettings settings, ScanCallback callback) BluetoothLeScanner.startScan(List<ScanFilter> filters, ScanSettings settings, PendingIntent callbackIntent)
<div class="cnblogs_code">
<pre>BluetoothLeScanner bluetoothLeScanner = bluetoothAdapter.getBluetoothLeScanner();
 filters.add(new ScanFilter.Builder()
 .setServiceUuid(ParcelUuid.fromString("0000000-0000-0000-0000-000000000000"))
 .build());
 bluetoothLeScanner.startScan(filters , new ScanSettings.Builder().build(),
 new ScanCallback() {
 @Override
 public void onScanResult(int callbackType, ScanResult result) {
 super.onScanResult(callbackType, result);
 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
 Log.d(MainActivity.ACTIVITY_SERVICE, "onScanResult:"+
 "\n Rssi() "+result.getRssi()+
 "\n AdvertisingSid() "+result.getAdvertisingSid()+
 "\n DataStatus() "+result.getDataStatus()+
 "\n ScanRecord() "+result.getScanRecord().getBytes()+
 "\n Address() "+result.getDevice().getAddress()+
 "\n Address() "+result.getDevice().getName()
 );
 }
 }

 @Override
 public void onBatchScanResults(List<ScanResult> results) {
 super.onBatchScanResults(results);
 }

 @Override
 public void onScanFailed(int errorCode) {
 super.onScanFailed(errorCode);
 }
 }
 );</pre>
</div>
 
建立连接:
在配对之前应该先cancelDiscovery()或者stopScan(callback)， 然后根据获取到蓝牙Mac地址连接即可
<div class="cnblogs_code">
<pre>BluetoothDevice device = bluetoothAdapter.getRemoteDevice(result.getDevice().getAddress());
device.connectGatt(MainActivity.this, false, new BluetoothGattCallback() {
 @Override
 public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
 super.onConnectionStateChange(gatt, status, newState);
 //status 连接或断开连接操作成功 BluetoothGatt.GATT_SUCCESS(0)
 //newState 新的连接状态 BluetoothProfile.STATE_DISCONNECTED(0-断开状态) BluetoothProfile.STATE_CONNECTED(1-连接状态)
 }
}
);</pre>
</div>
 
数据通信: ble写入操作
<div class="cnblogs_code">
<pre> private BluetoothGattCallback bluetoothGattCallback = new BluetoothGattCallback() {
 @Override
 public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
 super.onConnectionStateChange(gatt, status, newState);
 //status 连接或断开连接操作成功 BluetoothGatt.GATT_SUCCESS(0)
 //newState 新的连接状态 BluetoothProfile.STATE_DISCONNECTED(0-断开状态) BluetoothProfile.STATE_CONNECTED(1-连接状态)
 //获取远程设备提供的服务以及它们的特征和描述符。这步很重要而且是一个异步操作（这里需要时间直接接在下面写不可取）
 bluetoothGatt.discoverServices();
 //获取蓝牙GATT服务
 BluetoothGattService gattService = bluetoothGatt.getService(UUID.fromString("00000000-0000-0000-0000-000000000000"/*蓝牙协议*/));
 //GATT特性：用于构建 GATT 服务的基本数据元素
 BluetoothGattCharacteristic characteristic = gattService.getCharacteristic(UUID.fromString("00000000-0000-0000-0000-000000000000"));
 //设置数据，这里是我加密后的数据所以看起来有点不习惯
 byte[] data = {-27, 36, 65, -70, -8, 94, 18, -12, -56, 116, -68, -124, 92, -19, 94, -91 };
 //设置此特性的本地存储值。
 characteristic.setValue(data);
 //写入到远程蓝牙设备
 bluetoothGatt.writeCharacteristic(characteristic);



 }</pre>
</div>
 Ble通知读取操作
<div class="cnblogs_code">
<pre>//通知UUID
BluetoothGattCharacteristic gattCharacteristic = gattService.getCharacteristic(UUID.fromString("00000000-0000-0000-0000-000000000000"));
enableNotification(bluetoothGatt,true,gattCharacteristic);

public void enableNotification(BluetoothGatt bluetoothGatt, boolean enable, BluetoothGattCharacteristic characteristic) {
 if (bluetoothGatt == null || characteristic == null) {
 return;
 }
 if (!bluetoothGatt.setCharacteristicNotification(characteristic, enable)) {
 return;
 }
 //获取到Notify当中的Descriptor通道然后再进行注册
 List<BluetoothGattDescriptor> clientConfigs = characteristic.getDescriptors();
 if (clientConfigs == null || clientConfigs.size() ==0) {
 return;
 }
 if (enable) {
 for (BluetoothGattDescriptor clientConfig: clientConfigs) {
 clientConfig.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
 bluetoothGatt.writeDescriptor(clientConfig);
 }
 } else {
 for (BluetoothGattDescriptor clientConfig: clientConfigs) {
 clientConfig.setValue(BluetoothGattDescriptor.DISABLE_NOTIFICATION_VALUE);
 bluetoothGatt.writeDescriptor(clientConfig);
 }
 }
 }</pre>
</div>
  
来源：https://www.cnblogs.com/javaktolin/p/15459732.html

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Android 蓝牙开发