使用Android 6.0的BluetoothLeScanner.startScan无法发现设备

Question

我正在尝试使用BluatoothLeScanner.startScan功能而不是弃用的BluetoothAdapter.startLeScan.昨天我将我的Nexus 5更新到Android 6.0,从那时起我的应用程序就不再起作用了.我首先添加了此处所需的ACCESS_COARSE_LOCATION首选项, https://developer.android.com/about/versions/marshmallow/android-6.0-changes.html#behavior-hardware-id.然后我添加了此处所述的权限:https://developer.android.com/training/permissions/requesting.html.但最后它似乎无法正常工作,它不会发送回设备.

这是我的代码:

表现

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.stm.sensitronapp">
          <uses-sdk android:maxSdkVersion="23"/>
          <uses-feature android:name="android.hardware.bluetooth_le" android:required="true"/>

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

DeviceScanActivity

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
...

if (ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_COARSE_LOCATION)
            != PackageManager.PERMISSION_GRANTED){
        if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                Manifest.permission.ACCESS_COARSE_LOCATION)) {
        } else {
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.ACCESS_COARSE_LOCATION},
                    MY_PERMISSIONS_REQUEST_ACCESS_COARSE);
        }
    }

// Device scan callback.
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        if (ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_COARSE_LOCATION)
                == PackageManager.PERMISSION_GRANTED) {
            mScanCallback = new ScanCallback() {
                @Override
                public void onScanResult(int callbackType, ScanResult result) {
                    super.onScanResult(callbackType, result);
                    mLeDeviceListAdapter.addDevice(result.getDevice());
                    mLeDeviceListAdapter.notifyDataSetChanged();
                }
            };
        }
    } 
}
final BluetoothManager bluetoothManager =
            (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
mBluetoothAdapter = bluetoothManager.getAdapter();

if (mBluetoothAdapter.getState() == BluetoothAdapter.STATE_ON) {
        mSwipeRefreshLayout.setRefreshing(true);
        mLeDeviceListAdapter.clear();
        mBluetoothLeScanner = mBluetoothAdapter.getBluetoothLeScanner();
        if(ContextCompat.checkSelfPermission(this,
                    Manifest.permission.ACCESS_COARSE_LOCATION ) == PackageManager.PERMISSION_GRANTED) {
                mBluetoothLeScanner.startScan(mScanCallback);
            }
        }

编辑:解决这个问题我只打开了GPS.以这种方式以编程方式执行它很容易.

Answer 1

如果授予权限,请尝试:打开GPS.

Answer 2

你是应用程序在启动时提示输入位置权限吗？如果不是,请在其他地方处理代码,以便提示它.

此外,您可以检查此项以测试您的应用是否正常运行:

打开设置>应用> YourApplication>权限并启用位置,然后尝试扫描结果.

仅当您在清单上提供了ACCESS_COARSE_LOCATION时,才会在权限下列出位置.