在Android系统中，可以使用BluetoothLeScanner类来进行蓝牙低能耗设备的扫描和配对。下面是一个示例代码，演示如何选择蓝牙低能耗设备进行配对。

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothManager;
import android.bluetooth.le.BluetoothLeScanner;
import android.bluetooth.le.ScanCallback;
import android.bluetooth.le.ScanResult;
import android.bluetooth.le.ScanSettings;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.support.annotation.RequiresApi;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;

import java.util.List;

@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
public class MainActivity extends AppCompatActivity {

    private static final String TAG = MainActivity.class.getSimpleName();

    private BluetoothAdapter mBluetoothAdapter;
    private BluetoothLeScanner mBluetoothLeScanner;
    private Handler mHandler;
    private boolean mScanning;

    // 扫描10秒
    private static final long SCAN_PERIOD = 10000;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mHandler = new Handler();

        // 初始化蓝牙适配器
        final BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
        mBluetoothAdapter = bluetoothManager.getAdapter();

        // 初始化蓝牙低能耗扫描器
        mBluetoothLeScanner = mBluetoothAdapter.getBluetoothLeScanner();
    }

    // 开始扫描蓝牙低能耗设备
    private void startLeScan() {
        ScanSettings settings = new ScanSettings.Builder()
                .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
                .build();

        mBluetoothLeScanner.startScan(null, settings, mScanCallback);
        mScanning = true;

        // 扫描SCAN_PERIOD毫秒后停止扫描
        mHandler.postDelayed(new Runnable() {
            @Override
            public void run() {
                stopLeScan();
            }
        }, SCAN_PERIOD);
    }

    // 停止扫描蓝牙低能耗设备
    private void stopLeScan() {
        mBluetoothLeScanner.stopScan(mScanCallback);
        mScanning = false;
    }

    // 扫描回调函数
    private ScanCallback mScanCallback = new ScanCallback() {
        @Override
        public void onScanResult(int callbackType, ScanResult result) {
            BluetoothDevice device = result.getDevice();
            Log.d(TAG, "扫描到设备：" + device.getName() + " " + device.getAddress());
            // 进行设备配对操作
            // ...
        }

        @Override
        public void onScanFailed(int errorCode) {
            Log.e(TAG, "扫描失败，错误码：" + errorCode);
        }
    };

    @Override
    protected void onResume() {
        super.onResume();
        // 检查蓝牙是否已经打开
        if (!mBluetoothAdapter.isEnabled()) {
            // 如果蓝牙未打开，则请求打开蓝牙
            mBluetoothAdapter.enable();
        }

        // 开始扫描蓝牙低能耗设备
        startLeScan();
    }

    @Override
    protected void onPause() {
        super.onPause();
        // 停止扫描蓝牙低能耗设备
        stopLeScan();
    }
}

以上代码示例通过BluetoothLeScanner类实现了蓝牙低能耗设备的扫描和配对操作。在startLeScan()方法中，使用mBluetoothLeScanner.startScan()方法开始扫描低能耗设备，设置了扫描模式为SCAN_MODE_LOW_LATENCY，并在一定时间后调用stopLeScan()方法停止扫描。在mScanCallback中，可以通过result.getDevice()获取到扫描到的低能耗设备，并进行配对操作。