这个错误通常是因为应用程序没有正确注册扫描器导致的。以下是一个示例代码,展示了如何注册和使用BluetoothLeScanner:
private BluetoothAdapter bluetoothAdapter;
private BluetoothLeScanner bluetoothLeScanner;
private ScanCallback scanCallback;
// 初始化蓝牙适配器和扫描器
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
bluetoothLeScanner = bluetoothAdapter.getBluetoothLeScanner();
// 创建扫描回调
scanCallback = new ScanCallback() {
@Override
public void onScanResult(int callbackType, ScanResult result) {
// 处理扫描结果
}
@Override
public void onScanFailed(int errorCode) {
// 处理扫描失败
Log.d("BluetoothLeScanner", "Scan failed with error code: " + errorCode);
}
};
// 开始扫描
bluetoothLeScanner.startScan(scanCallback);
确保已经打开了蓝牙和位置权限。如果没有打开,可以添加以下代码请求权限:
private static final int REQUEST_ENABLE_BT = 1;
private static final int REQUEST_LOCATION_PERMISSION = 2;
// 请求打开蓝牙
if (bluetoothAdapter == null || !bluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
// 请求位置权限
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
REQUEST_LOCATION_PERMISSION);
}
确保在AndroidManifest.xml文件中正确添加了上述权限。