问Wifimanager.getConfiguredNetworks()返回null
EN

Stack Overflow用户

提问于 2017-05-15 20:09:50

回答 2查看 5.2K关注 0票数 2

我在网上学习了一些教程，试图在android上创建一个wifi扫描仪，但是我在WifiManager的getConfiguredNetworks()方法上遇到了麻烦。它经常返回null，而不是预期的列表。

我在网上做了一些搜索，我的代码似乎一直在抛出一个RemoteException。即使在阅读了关于：http://docs.oracle.com/javase/7/docs/api/java/rmi/RemoteException.html的文档之后，我仍然不了解RemoteExcecption是什么或如何解决它。

下面是我的代码片段：

    wifi=(WifiManager)getApplicationContext().getSystemService(Context.WIFI_SERVICE);
    wifi.setWifiEnabled(true);
    Log.d("WifiInfo", "info is: " + info);

    //  list available network

    List<WifiConfiguration> configurations = wifi.getConfiguredNetworks(); //configurations is null
    Log.d("List<WifiConfig>", "configurations is: " + configurations); //error thrown here
    // Is WiFi on?
    if (wifi.isWifiEnabled()) {
        // Check for existing APs.
        for(WifiConfiguration config : configurations) {
            Log.d("CONFIG", config.toString());
            myItems.add(config.toString());
        }
    }

有人能帮我吗？

android

wifimanager

回答 2

Stack Overflow用户

回答已采纳

发布于 2017-05-15 20:16:29

用这个代码..。

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    WifiManager wifi;
    ListView lv;
    TextView textStatus;
    Button buttonScan;
    int size = 0;
    List<ScanResult> results;

    String ITEM_KEY = "key";
    ArrayList<HashMap<String, String>> arraylist = new ArrayList<HashMap<String, String>>();
    SimpleAdapter adapter;

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


       // textStatus = (TextView) findViewById(R.id.test1);
        buttonScan = (Button) findViewById(R.id.btn);
        buttonScan.setOnClickListener(MainActivity.this);
        lv = (ListView) findViewById(R.id.listview_item);

        wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        if (wifi.isWifiEnabled() == false) {
            Toast.makeText(getApplicationContext(), "wifi is disabled..making it enabled", Toast.LENGTH_LONG).show();
            wifi.setWifiEnabled(true);
        }
        this.adapter = new SimpleAdapter(MainActivity.this, arraylist, R.layout.raw, new String[]{ITEM_KEY}, new int[]{R.id.row});
        lv.setAdapter(this.adapter);

        registerReceiver(new BroadcastReceiver() {
            @Override
            public void onReceive(Context c, Intent intent) {


                results = wifi.getScanResults();
                size = results.size();
            }
        }, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));


        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Toast.makeText(MainActivity.this, arraylist.get(position).toString(), Toast.LENGTH_SHORT).show();

                connectToAP(arraylist.get(position).get("key"), "");

            }
        });
    }

    public void connectToAP(String ssid, final String passkey) {


        final WifiConfiguration wifiConfiguration = new WifiConfiguration();

        final String networkSSID = ssid;
        final String[] networkPass = {passkey};
        final String[] password = {""};
        for (ScanResult result : results) {
            if (result.SSID.equals(networkSSID)) {

                String securityMode = getScanResultSecurity(result);

                if (securityMode.equals("PSK")) {
                    final AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
                    dialog.setTitle("Password");
                    dialog.setMessage("Enter Passsword");
                    final EditText editText = new EditText(MainActivity.this);
                    LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);
                    editText.setLayoutParams(lp);
                    dialog.setView(editText);


                    dialog.setPositiveButton("YES", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {

                            password[0] = editText.getText().toString();
                            wifiConfiguration.SSID = "\"" + networkSSID + "\"";
                            wifiConfiguration.preSharedKey = "\"" + editText.getText().toString() + "\"";
                            wifiConfiguration.hiddenSSID = true;
                            wifiConfiguration.status = WifiConfiguration.Status.ENABLED;
                            wifiConfiguration.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);
                            wifiConfiguration.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);
                            wifiConfiguration.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK);
                            wifiConfiguration.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);
                            wifiConfiguration.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);
                            wifiConfiguration.allowedProtocols.set(WifiConfiguration.Protocol.RSN);
                            wifiConfiguration.allowedProtocols.set(WifiConfiguration.Protocol.WPA);

                            int res = wifi.addNetwork(wifiConfiguration);

                            wifi.enableNetwork(res, true);

                            boolean changeHappen = wifi.saveConfiguration();

                            if (res != -1 && changeHappen) {

                                // .connectedSsidName = networkSSID;

                            } else {
                                // Log.d(TAG, "*** Change NOT happen");
                            }

                            wifi.setWifiEnabled(true);

                        }
                    });

                    dialog.setNegativeButton("NO", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            dialog.cancel();
                        }
                    });
                    dialog.show();

                }

                if (securityMode.equalsIgnoreCase("OPEN")) {

                    wifiConfiguration.SSID = "\"" + networkSSID + "\"";
                    wifiConfiguration.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
                    int res = wifi.addNetwork(wifiConfiguration);
                    boolean b = wifi.enableNetwork(res, true);
                    wifi.setWifiEnabled(true);

                } else if (securityMode.equalsIgnoreCase("WEP")) {

                    wifiConfiguration.SSID = "\"" + networkSSID + "\"";
                    wifiConfiguration.wepKeys[0] = "\"" + password[0] + "\"";
                    wifiConfiguration.wepTxKeyIndex = 0;
                    wifiConfiguration.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
                    wifiConfiguration.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP40);
                    int res = wifi.addNetwork(wifiConfiguration);

                    boolean b = wifi.enableNetwork(res, true);

                    wifi.setWifiEnabled(true);
                }


            }
        }
    }

    public String getScanResultSecurity(ScanResult scanResult) {

        final String cap = scanResult.capabilities;
        final String[] securityModes = {"WEP", "PSK", "EAP"};

        for (int i = securityModes.length - 1; i >= 0; i--) {
            if (cap.contains(securityModes[i])) {
                return securityModes[i];
            }
        }

        return "OPEN";


    }

    public void onClick(View view) {
        arraylist.clear();
        wifi.startScan();

        Toast.makeText(this, "Scanning...." + size, Toast.LENGTH_SHORT).show();
        try {
            size = size - 1;
            while (size >= 0) {
                HashMap<String, String> item = new HashMap<String, String>();
                item.put(ITEM_KEY, results.get(size).SSID);
                item.put("capablity", results.get(size).capabilities);
                adapter.notifyDataSetChanged();

                arraylist.add(item);
                size--;
            }
        } catch (Exception e) {
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.admin.wifi.MainActivity">



    <ListView
        android:id="@+id/listview_item"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">


    </ListView>
    <Button
        android:id="@+id/btn"
        android:layout_alignParentBottom="true"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="scan" />


</RelativeLayout>

raw.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:id="@+id/row"
        android:layout_height="wrap_content" />

</LinearLayout>

少女节

票数 1

Stack Overflow用户

发布于 2020-10-29 07:19:51

我刚才也是这样的。首先:在关闭wifi时，getConfiguredNetworks()总是返回null。而且，WifiService在setWifiEnabled(true)和getConfiguredNetworks()之间似乎需要一点时间。我创建了一个小循环，只打印了一个日志：

    wifiMgr.setWifiEnabled(true); // else we won't be able to read the networks
    while (wifiMgr.getWifiState() != WIFI_STATE_ENABLED) {
      LogIf.d("FOO", "waiting for wifi-system to provide network-data");
    }
    for (WifiConfiguration cfg : wifiMgr.getConfiguredNetworks()) {
      ..