java - Android Wifi getScanResult()返回空列表

我想扫描周围的WiFi网络并显示它们，但是当我使用WifiManager.getScanResult（）时，我得到一个空列表。

我已经在清单中请求了权限，我尝试使用运行时，但调试器从未进入（我读到“正常权限”，所以我认为这是正常的：D，但在其他帖子上，他们使用它）

主要：

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    listeViewWifi = (ListView) findViewById(R.id.listViewWifi);

    wifiManager = (WifiManager) this.getApplicationContext().getSystemService(Context.WIFI_SERVICE);

    listeWifiItem = new ArrayList<WifiItem>();
    wifiAdapter = new WifiAdapter(this, listeWifiItem);
    listeViewWifi.setAdapter(wifiAdapter);

    broadcastReceiver = new WifiBroadcastReceiver();

    registerReceiver(broadcastReceiver, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));

    boutonRechercher = (Button) findViewById(R.id.buttonRefresh);
    boutonRechercher.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            if (wifiManager != null) {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M
                        && (checkSelfPermission(Manifest.permission.CHANGE_WIFI_STATE) != PackageManager.PERMISSION_GRANTED
                        || checkSelfPermission(Manifest.permission.ACCESS_WIFI_STATE) != PackageManager.PERMISSION_GRANTED)) {
                    requestPermissions(new String[]{Manifest.permission.ACCESS_WIFI_STATE, Manifest.permission.CHANGE_WIFI_STATE},
                            WIFI_PERMISSION);
                }
                wifiManager.setWifiEnabled(true);
                wifiManager.startScan();
            }
        }
    });
}
@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    if (requestCode == WIFI_PERMISSION
            && grantResults[0] == PackageManager.PERMISSION_GRANTED
            && grantResults[1] == PackageManager.PERMISSION_GRANTED) {
        wifiManager.setWifiEnabled(true);
        wifiManager.startScan();
    }
    else {
        Toast.makeText(MainActivity.this, "Allow Permissions", Toast.LENGTH_LONG).show();
    }
}

接收方：

public class WifiBroadcastReceiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
    WifiManager wifiManager = ((MainActivity) context).getCurrentWifiManager();
    WifiAdapter wifiAdapter = ((MainActivity) context).getWifiAdapter();
    List<WifiItem> listeWifiItem = ((MainActivity) context).getListeWifiItem();

    if (wifiManager != null) {

        List<ScanResult> listeScan = wifiManager.getScanResults();  //empty

        listeWifiItem.clear();

        for (ScanResult scanResult : listeScan) {
            WifiItem item = new WifiItem();

            item.setAdresseMac(scanResult.BSSID);
            item.setAPName(scanResult.SSID);
            item.setForceSignal(scanResult.level);

            Log.d("FormationWifi", scanResult.SSID + " LEVEL "
                    + scanResult.level);

            listeWifiItem.add(item);
        }

        wifiAdapter.notifyDataSetChanged();

    }
}
}

最佳答案

您必须要求：

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        requestPermissions(new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, 1001);
    }

在检查之后，位置在吗？
You can use this library为您的目标。