如何在android中连续启动和停止扫描ble

Question

为了连续扫描广告数据，我尝试启动和停止 mBluetoothAdapter.stopLeScan(mLeScanCallback) 函数，但它仍然只发生一次。当我尝试调用扫描两次时，在 logcat 中我可以看到 LE 扫描已经开始，因为第二个调用没有执行。此处如何调用重复扫描和停止。

private void scanLeDevice(final boolean enable) {

    if (enable){
        // Stops scanning after a pre-defined scan period.
        mHandler.postDelayed(new Runnable() {
            @Override
            public void run() {
                mScanning = false;
                mBluetoothAdapter.stopLeScan(mLeScanCallback);
                System.out.println("hello");

                invalidateOptionsMenu();
            }
        }, SCAN_PERIOD);
        System.out.println(SCAN_PERIOD);
        mScanning = true;

        System.out.println("starttt 1!");
        mBluetoothAdapter.startLeScan(mLeScanCallback);
        //////

        mHandler.postDelayed(new Runnable() {
            @Override
            public void run() {
                mScanning = false;
                mBluetoothAdapter.stopLeScan(mLeScanCallback);
                System.out.println("hello");

                invalidateOptionsMenu();
            }
        }, SCAN_PERIOD);
        System.out.println(SCAN_PERIOD);
        mScanning = true;

        System.out.println("starttt 1!");
        mBluetoothAdapter.startLeScan(mLeScanCallback);
                    //////////


    }
    else
    {
        mScanning = false;
        mBluetoothAdapter.stopLeScan(mLeScanCallback);
    }
    invalidateOptionsMenu();
}

Answer 1

这对我来说效果很好，

我有一个方法叫discoverBLEdevices，在onCreate中调用。

@SuppressLint("NewApi")
private void discoverBLEDevices() {
    // TODO Auto-generated method stub
     startScan.run();
     Log.e("BLE_Scanner", "DiscoverBLE");
}

我有一个startScanRunnable，我在其中启动扫描并调用另一个runnable来停止扫描，如下所示：

private Runnable startScan = new Runnable() {
    @Override
    public void run() {
        scanHandler.postDelayed(stopScan, 500);
        mBLEAdapter.startLeScan(mLeScanCallback);
        Log.e("BLE_Scanner", "Start Scan");
    }
};

500 毫秒后，我调用了一个名为 stopScan 的可运行对象，它会停止扫描并再次调用 startScan 可运行对象。

private Runnable stopScan = new Runnable() {
    @Override
    public void run() {
        mBLEAdapter.stopLeScan(mLeScanCallback);
        scanHandler.postDelayed(startScan, 10);
        Log.e("BLE_Scanner", "Stop Scan");
    }
};

我的回调如下：

// Device scan callback.
@SuppressLint("NewApi")
private BluetoothAdapter.LeScanCallback mLeScanCallback = new BluetoothAdapter.LeScanCallback() {

        @SuppressLint("NewApi")
        public void onLeScan(final BluetoothDevice device, int rssi,
                byte[] scanRecord) {

            String Address = device.getAddress();
            String Name = device.getName();
            Log.e("mLeScanCallback",""+Address +" : "+Name);
        }
    };

整个代码：

import android.annotation.SuppressLint;
import android.app.Service;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothManager;
import android.content.Intent;
import android.os.Handler;
import android.os.IBinder;
import android.util.Log;
import android.widget.Toast;

@SuppressLint("NewApi")
public class BluetoothLE extends Service {

private BluetoothAdapter mBLEAdapter;
private BluetoothManager manager;
private Handler scanHandler = new Handler();

@Override
public IBinder onBind(Intent intent) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public void onCreate() {
    // TODO Auto-generated method stub
    super.onCreate();
    turnonBLE();
    discoverBLEDevices();
 }

@SuppressLint("NewApi")
private void turnonBLE() {
    // TODO Auto-generated method stub
    manager = (BluetoothManager) getSystemService(BLUETOOTH_SERVICE);
    mBLEAdapter = manager.getAdapter();
    mBLEAdapter.enable();
    Toast.makeText(getApplicationContext(), "BTLE ON Service",
            Toast.LENGTH_LONG).show();
    Log.e("BLE_Scanner", "TurnOnBLE");}

@SuppressLint("NewApi")
private void discoverBLEDevices() {
    // TODO Auto-generated method stub
    startScan.run();
    Log.e("BLE_Scanner", "DiscoverBLE");
}


private Runnable startScan = new Runnable() {
    @Override
    public void run() {
        scanHandler.postDelayed(stopScan, 500);
        mBLEAdapter.startLeScan(mLeScanCallback);
    }
};


// Device scan callback.
@SuppressLint("NewApi")
private BluetoothAdapter.LeScanCallback mLeScanCallback = new BluetoothAdapter.LeScanCallback() {

        @SuppressLint("NewApi")
        public void onLeScan(final BluetoothDevice device, int rssi,
                byte[] scanRecord) {

            String Address = device.getAddress();
            String Name = device.getName();
            Log.e("mLeScanCallback",""+Address +" : "+Name);
            }
    };


private Runnable stopScan = new Runnable() {
    @Override
    public void run() {
        mBLEAdapter.stopLeScan(mLeScanCallback);
        scanHandler.postDelayed(startScan, 10);
    }
};
}

Answer 2

如果它没有更新，我通过打开/关闭蓝牙适配器添加了几行。在我的情况下工作正常。

fun discoverBLEDevices(){
    startScan.run()
    Log.d("Scan", " Discover BLE")
}

private val startScan:Runnable = Runnable {
    scanHandler.postDelayed(stopScan,10000)
    bluetoothLeScanner.startScan(bleScanner)
    // bluetoothAdapter.enable()
    Log.e("BLE_Scanner", "Start Scan")
}

private val stopScan:Runnable = Runnable {
    bluetoothLeScanner.stopScan(bleScanner)
    bluetoothAdapter.disable()
    bluetoothAdapter.enable()
    scanHandler.postDelayed(startScan, 1000)
    Log.e("BLE_Scanner", "Stop Scan")
}