Android Wifimanager.getConfiguredNetworks（）がnullを返します

Question

私はAndroidスタジオでWi-Fiスキャナを作成しようとするとオンラインでいくつかのチュートリアルを実行しましたが、WifiManagerのgetConfiguredNetworks（）メソッドに問題があります。期待されるリストの代わりに常にnullを返します。

私はオンラインで検索しましたが、私のコードがRemoteExceptionをスローしているようです。ドキュメントを読んだ後：http://docs.oracle.com/javase/7/docs/api/java/rmi/RemoteException.html、私はまだRemoteExcecptionが何であるか、それを解決する方法を理解していません。以下は

私のコードの抜粋です：

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()); 
     } 
    } 

誰も私を助けることができる、してください？

Answer 1

使用このコード..

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> 

maifest