private void scanLeDevice(final boolean enable) {
   if (enable) {
     mHandler.postDelayed(
         new Runnable() {
           @Override
           public void run() {
             if (Build.VERSION.SDK_INT < 21) {
               mBluetoothAdapter.stopLeScan(mLeScanCallback);
             } else {
               mLEScanner.stopScan(mScanCallback);
             }
           }
         },
         SCAN_PERIOD);
     if (Build.VERSION.SDK_INT < 21) {
       mBluetoothAdapter.startLeScan(mLeScanCallback);
     } else {
       mLEScanner.startScan(filters, settings, mScanCallback);
     }
   } else {
     if (Build.VERSION.SDK_INT < 21) {
       mBluetoothAdapter.stopLeScan(mLeScanCallback);
     } else {
       mLEScanner.stopScan(mScanCallback);
     }
   }
 }