<!-- 藍(lán)牙搜索配對(duì) -->
  <uses-permission android:name="android.permission.BLUETOOTH" />
  <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
  <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
  <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
  <uses-permission android:name="android.permission.BLUETOOTH_SCAN" />
  <!--   操縱藍(lán)牙的開(kāi)啟-->
  <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />

  <!-- 如果應(yīng)用必須安裝在支持藍(lán)牙的設(shè)備上，可以將下面的required的值設(shè)置為true。-->
  <uses-feature
      android:name="android.hardware.bluetooth_le"
      android:required="false" />

@Override
   protected void onCreate(@Nullable Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
           //不支持藍(lán)牙設(shè)備
           finish();
      } else {
           //支持藍(lán)牙設(shè)備
  }

final BluetoothManager bluetoothManager =(BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
BluetoothAdapter bluetoothAdapter = bluetoothManager.getAdapter();

if (bluetoothAdapter == null || !bluetoothAdapter.isEnabled()) {
   //開(kāi)啟設(shè)備的藍(lán)牙鏈接
   bluetoothAdapter.enable();//開(kāi)啟藍(lán)牙
//動(dòng)態(tài)判斷是否擁有位置權(quán)限ACCESS_COARSE_LOCATION 或ACCESS_FINE_LOCATION ，然后再執(zhí)行藍(lán)牙掃描
} else {
  //動(dòng)態(tài)判斷是否擁有位置權(quán)限ACCESS_COARSE_LOCATION 或ACCESS_FINE_LOCATION，然后再執(zhí)行藍(lán)牙掃描
}

ActivityResultLauncher<Intent> launcher = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), result -> {
           if (result.getResultCode() == RESULT_OK) {
               //處理返回結(jié)果
          }
});

Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); //創(chuàng)建一個(gè)藍(lán)牙啟動(dòng)的意圖
launcher.launch(enableBtIntent);//使用launcer啟動(dòng)這個(gè)意圖就可以了。

public class BluetoothFoundReceiver extends BroadcastReceiver {
   @Override
   public void onReceive(Context context, Intent intent) {
       String action = intent.getAction();
       //監(jiān)聽(tīng)藍(lán)牙狀態(tài)之后，發(fā)送消息
       try {
           if (BluetoothAdapter.ACTION_DISCOVERY_STARTED.equals(action)) {
//開(kāi)始掃描
          } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
               //結(jié)束掃描
          } else if (BluetoothDevice.ACTION_FOUND.equals(action)) {
               //發(fā)現(xiàn)設(shè)備,每掃碼到一個(gè)設(shè)備，都會(huì)觸發(fā)一次
                BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
               //我們可以得到藍(lán)牙設(shè)備
          } else if (action.equals(BluetoothAdapter.ACTION_STATE_CHANGED)) {
               //藍(lán)牙開(kāi)關(guān)狀態(tài)
             
               int statue = bluetoothAdapter.getState();
               switch (statue) {
                   case BluetoothAdapter.STATE_OFF:
                       Log.e(TAG, "藍(lán)牙狀態(tài)：,藍(lán)牙關(guān)閉");
                       break;
                   case BluetoothAdapter.STATE_ON:
                       Log.e(TAG, "藍(lán)牙狀態(tài)：,藍(lán)牙打開(kāi)");
                     
                       break;
                   case BluetoothAdapter.STATE_TURNING_OFF:
                       Log.e(TAG, "藍(lán)牙狀態(tài)：,藍(lán)牙正在關(guān)閉");
                       break;
                   case BluetoothAdapter.STATE_TURNING_ON:
                       Log.e(TAG, "藍(lán)牙狀態(tài)：,藍(lán)牙正在打開(kāi)");
                       break;
              }
          }
      } catch (Exception e) {
           e.printStackTrace();
      }
  }
}

bluetoothFoundReceiver = new BluetoothFoundReceiver();
       IntentFilter filter = new IntentFilter();
       filter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);//連接藍(lán)牙，斷開(kāi)藍(lán)牙
       filter.addAction(BluetoothDevice.ACTION_FOUND);//找到設(shè)備的廣播
       filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);//搜索完成的廣播
       filter.addAction(BluetoothDevice.ACTION_BOND_STATE_CHANGED);//狀態(tài)改變 配對(duì)開(kāi)始時(shí)，配對(duì)成功時(shí)
       registerReceiver(bluetoothFoundReceiver, filter);

@Override
   protected void onDestroy() {
       if (bluetoothFoundReceiver != null)
           unregisterReceiver(bluetoothFoundReceiver); //停止監(jiān)聽(tīng)
       super.onDestroy();
  }

bluetoothAdapter.startLeScan(leScanCallback);  //查找
bluetoothAdapter.stopLeScan(leScanCallback); //停止查找

BluetoothLeScanner scanner = bluetoothAdapter.getBluetoothLeScanner();
 //不進(jìn)行權(quán)限驗(yàn)證
ScanCallback callback = new ScanCallback() {
           @Override
           public void onScanResult(int callbackType, ScanResult result) {
               BluetoothDevice device = result.getDevice();//得到設(shè)備
//               Log.e(TAG, "發(fā)現(xiàn)設(shè)備" + device.getName());
          }

           @Override
           public void onScanFailed(int errorCode) {
               super.onScanFailed(errorCode);
               Log.e(TAG, "搜索錯(cuò)誤" + errorCode);
          }
      };
scanner.startScan(callback);

ScanFilter sn =new ScanFilter.Builder().setDeviceName("藍(lán)牙設(shè)備的名稱(chēng)").setServiceUuid(ParcelUuid.fromString("我們的設(shè)備的Service UUID")).build();
List<ScanFilter> scanFilters=new ArrayList<>();
scanFilters.add(sn);
scanner.startScan(scanFilters, new ScanSettings.Builder().build(),callback);

if (bluetoothAdapter.isDiscovering()) {//是否在掃描
  bluetoothAdapter.cancelDiscovery(); //停止掃描
}
//查找藍(lán)牙
bluetoothAdapter.startDiscovery();

BluetoothDevice device;// 當(dāng)我們通過(guò)掃描得到device對(duì)象之后，進(jìn)行Gatt服務(wù)創(chuàng)建
BluetoothGatt bluetoothGatt = device.connectGatt(this, false, gattCallback);

String SERVICE_UUID="00000-000000-000000-000000";//這個(gè)是我要鏈接的藍(lán)牙設(shè)備的ServiceUUID

BluetoothGattCallback gattCallback = new BluetoothGattCallback() {
    //GATT的鏈接狀態(tài)回調(diào)
           @Override
           public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
               super.onConnectionStateChange(gatt, status, newState);
               if (newState == BluetoothProfile.STATE_CONNECTED) {
          gatt.discoverServices();
          Log.v(TAG, "連接成功");
      } else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
          Log.e(TAG, "連接斷開(kāi)");
      } else if (newState == BluetoothProfile.STATE_CONNECTING) {
          //TODO 在實(shí)際過(guò)程中，該方法并沒(méi)有調(diào)用
          Log.e(TAG, "連接中....");
              }
          }
    //獲取GATT服務(wù)發(fā)現(xiàn)后的回調(diào)
    @Override
   public void onServicesDiscovered(BluetoothGatt gatt, int status) {
       if (status == BluetoothGatt.GATT_SUCCESS) {
           Log.e(TAG, "GATT_SUCCESS"); //服務(wù)發(fā)現(xiàn)
           for (BluetoothGattService bluetoothGattService : gatt.getServices()) {
               Log.e(TAG, "Service_UUID" + bluetoothGattService.getUuid()); // 我們可以遍歷到該藍(lán)牙設(shè)備的全部Service對(duì)象。然后通過(guò)比較Service的UUID，我們可以區(qū)分該服務(wù)是屬于什么業(yè)務(wù)的
               if (SERVICE_UUID.equals(bluetoothGattService.getUuid().toString())) {
                 
                   for (BluetoothGattCharacteristic characteristic : bluetoothGattService.getCharacteristics()) {
                       prepareBroadcastDataNotify(gatt, characteristic); //給滿足條件的屬性配置上消息通知
                  }
                   return;//結(jié)束循環(huán)操作
              }
          }
      } else {
           Log.e(TAG, "onServicesDiscovered received: " + status);
      }
  }
   
   //藍(lán)牙設(shè)備發(fā)送消息后的自動(dòng)監(jiān)聽(tīng)
   @Override
   public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
       // readUUID 是我要鏈接的藍(lán)牙設(shè)備的消息讀UUID值，跟通知的特性的UUID比較。這樣可以避免其他消息的污染。
       if (READ_UUID.equals(characteristic.getUuid().toString())) {
           try {
               String chara = new String(characteristic.getValue(), "UTF-8");
               Log.e(TAG, "消息內(nèi)容:" + chara);
          } catch (UnsupportedEncodingException e) {
               e.printStackTrace();
          }
      }
  }
};

@SuppressLint("MissingPermission")
   private void prepareBroadcastDataNotify(BluetoothGatt mBluetoothGatt, BluetoothGattCharacteristic characteristic) {
       Log.e(TAG, "CharacteristicUUID:" + characteristic.getUuid().toString());
       int charaProp = characteristic.getProperties();
       //判斷屬性是否支持消息通知
       if ((charaProp | BluetoothGattCharacteristic.PROPERTY_NOTIFY) > 0) {
           BluetoothGattDescriptor descriptor =
                   characteristic.getDescriptor(UUID.fromString(UUIDManager.READ_DEDSCRIPTION_UUID));
           if (descriptor != null) {
               //注冊(cè)消息通知
               mBluetoothGatt.setCharacteristicNotification(characteristic, true);
               descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
               mBluetoothGatt.writeDescriptor(descriptor);
          }
      }
  }

String data ="0x12";
BluetoothGattCharacteristic writeCharact = bluetoothGattService.
               getCharacteristic(UUID.fromString(WRITE_UUID));
       //查找UUID是寫(xiě)的特性，并檢測(cè)是否擁有寫(xiě)權(quán)限
       if (writeCharact == null || writeCharact.getProperties() != BluetoothGattCharacteristic.PROPERTY_WRITE) {
           return ;//該特性沒(méi)有寫(xiě)的權(quán)限。所以無(wú)法傳入
      }
       // 當(dāng)數(shù)據(jù)傳遞到藍(lán)牙之后
       // 會(huì)回調(diào)BluetoothGattCallback里面的write方法
       writeCharact.setWriteType(BluetoothGattCharacteristic.WRITE_TYPE_NO_RESPONSE);
       // 將需要傳遞的數(shù)據(jù)轉(zhuǎn)為16進(jìn)制數(shù)
       writeCharact.setValue(data);
       bluetoothGatt.writeCharacteristic(writeCharact);

if (bluetoothGatt != null) {
           bluetoothGatt.close();
           bluetoothGatt.disconnect();
           bluetoothGatt = null;
}

gattCallback.disConnectBlue();//關(guān)閉GATT服務(wù)回調(diào)監(jiān)聽(tīng)