Android扫描蓝牙设备是个异步的过程，核心的步骤为：调用bluetoothAdapter的startDiscovery()进行设备扫描，扫描的结果通过广播接收处理！具体如下：

1.申请相关权限

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2.注册广播

1 private void registerBroadcast() {2         // Register for broadcasts when a device is discovered3         IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);4         mContext.registerReceiver(mReceiver, filter);5 6         // Register for broadcasts when discovery has finished7         filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);8         mContext.registerReceiver(mReceiver, filter);9     }

3.扫描设备

1 private void doDiscovery() {2         // If we're already discovering, stop it3         if (mBluetoothAdapter.isDiscovering()) {4             mBluetoothAdapter.cancelDiscovery();5         }6         // Request discover from BluetoothAdapter7         mBluetoothAdapter.startDiscovery();8     }

4.广播中处理扫描到的设备

1 private final BroadcastReceiver mReceiver = new BroadcastReceiver() { 2         @Override 3         public void onReceive(Context context, Intent intent) { 4             String action = intent.getAction(); 5              6             if (BluetoothDevice.ACTION_FOUND.equals(action)) { 7                 // TODO discovery finds a device 8                  9             } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED10                     .equals(action)) {11                 // TODO discovery is finished12             }13         }14     };