Android 10：如何获取未连接蓝牙设备的RSSI值

Question

我的布局中有一个按钮和一个 TextView。

我正在尝试获取BLE设备的信号强度值，目标是找到不需要连接的所需设备在哪里，为此我需要获取我附近所有设备的RSSI。我根据其他帖子编写了以下代码。

问题是我的设备从来没有进入ScanCallback函数，我不知道为什么。 有人可以指导如何解决问题吗？谢谢！

import ...

public class MainActivity extends AppCompatActivity {

    private BluetoothAdapter mBluetoothAdapter;
    private BluetoothLeScanner mBluetoothLeScanner;
    private ScanCallback mScanCallback;
    private Button mButton;
    private TextView mTextView;

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

        mButton = findViewById(R.id.button1);
        mTextView = findViewById(R.id.textView1);

        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        mBluetoothLeScanner = mBluetoothAdapter.getBluetoothLeScanner();

        mScanCallback = new ScanCallback() {
            @Override
            public void onScanResult(int callbackType, ScanResult result) {
                super.onScanResult(callbackType, result);
                int rssi = result.getRssi();
                mTextView.setText("RSSI: " + rssi);
            }
        };

        mButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (ActivityCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.BLUETOOTH_SCAN) != PackageManager.PERMISSION_GRANTED) {return;}
                mBluetoothLeScanner.startScan(mScanCallback);
            }
        });

    }
}

Answer 1

您可以这样搜索设备：

bluetoothAdapter.bluetoothLeScanner?.startScan(emptyList(), scanSetting, callback)

并使用此扫描回调：

    callback = object : ScanCallback() {
        override fun onScanResult(callbackType: Int, result: ScanResult?) {
            timber.d("device found name: ${result.device?.name} address: ${result.device?.address}")
            val rssi = result.rssi
        }

        override fun onScanFailed(errorCode: Int) {
            onError("BLE scan failed with error code: $errorCode", errorCode)
        }
    }