Android BLE 发现问题

debugcn 发表于 Dev

卢卡

我正在开发带有蓝牙的 Android 应用程序，但有时我在发现 LE 设备时遇到问题：通常发现回调会返回找到的设备，但有时会停止工作并且不返回设备。

我在不同的设备（三星、LG）和不同的 Android 版本（8.0、6.0、4.4）上测试了代码（在调试模式下），但问题是一样的，不是系统的，一段时间后，它恢复正常。

我已经应用了在互联网上找到的所有建议：

但问题仍然存在。

下面是清单的片段：

.
.
.
<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

<uses-feature android:name="android.hardware.location.gps" />
<uses-feature android:name="android.hardware.bluetooth_le" android:required="true"/>
.
.
.

和蓝牙代码：

public BLEH_RES StartDiscovery()
{
    .
    .
    .
    CheckPermission();

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)
        return(scanLeDevice21(true));
    else
        return(scanLeDevice18(true));
}

 /**
 * Scan BLE devices on Android API 20 to last version (Android 9.0)
 *
 * @param enable Enable scan
 */
@RequiresApi(21)
private BLEH_RES scanLeDevice21(boolean enable)
{
    bluetoothLeScanner = bluetoothAdapter.getBluetoothLeScanner();

    if (bluetoothLeScanner == null)
        return(BLEH_RES.BLE_NOT_SUPPORTED);

    if (enable)
    {
        ScanSettings.Builder scanSettings = new ScanSettings.Builder();
        scanSettings.setScanMode(SCAN_MODE_LOW_LATENCY);
        bluetoothLeScanner.startScan(null, scanSettings.build(), BLEScanCallback);
    }
    else
        bluetoothLeScanner.stopScan(BLEScanCallback);

    return(BLEH_RES.OK);
}

/**
 * Scan BLE devices on Android API 18 to 20
 *
 * @param enable Enable scan
 */
private BLEH_RES scanLeDevice18(boolean enable)
{
    if(bluetoothAdapter == null)
        return(BLEH_RES.BT_NOT_SUPPORTED);


    if (enable) 
    {
        bluetoothAdapter.startDiscovery();
        bluetoothAdapter.startLeScan(mLeScanCallback);
    }
    else
    {
        bluetoothAdapter.cancelDiscovery();
        bluetoothAdapter.stopLeScan(mLeScanCallback);
    }

    return(BLEH_RES.OK);
}

@RequiresApi(21)
private ScanCallback BLEScanCallback = new ScanCallback()
{
    @Override
    public void onScanResult(int callbackType, ScanResult result)
    {
        addDevice(result.getDevice(), result.getRssi(), result.getScanRecord().getBytes());
    }

    @Override
    public void onScanFailed(int errorCode)
    {
        for(ErrorEvent ee:errorEventList)
            ee.onError(BLEH_EVENT_ERROR.SCAN_FAILED);
    }
};

private BluetoothAdapter.LeScanCallback mLeScanCallback = new BluetoothAdapter.LeScanCallback()
{
    @Override
    public void onLeScan(final BluetoothDevice bluetoothDevice, int rssi,byte[] scanRecord)
    {
        addDevice(bluetoothDevice, rssi, scanRecord);
    }
};