I'm making an app that lists all the wifi networks available and connect to one selected by the user

Question

I'm trying to build an app that scans for the available wifi connections and lists them in a list view. The user can select one and connect to the wifi. My code doesn't seem to work. I've added the following permissions in the manifest:

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
 <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>   
 <uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/>

Here is the main activity:

public class MainActivity extends ListActivity {
    WifiManager mainWifiObj;
    WifiScanReceiver wifiScanReceiver;
    ListView list;
    String wifiList[];
    EditText pass;

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

        list=getListView();
        mainWifiObj = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
        wifiScanReceiver = new WifiScanReceiver();
        mainWifiObj.startScan();

        // listening to single list item on click
        list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                // selected item
                String ssid = ((TextView) view).getText().toString();
                connectToWifi(ssid);
                Toast.makeText(MainActivity.this,"Wifi SSID : "+ssid,Toast.LENGTH_SHORT).show();

            }
        });
    }

    protected void onPause() {
        unregisterReceiver(wifiScanReceiver);
        super.onPause();
    }

    protected void onResume() {
        registerReceiver(wifiScanReceiver, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
        super.onResume();
    }
    class WifiScanReceiver extends BroadcastReceiver {
        @SuppressLint("UseValueOf")
        public void onReceive(Context c, Intent intent) {
            List<ScanResult> wifiScanList = mainWifiObj.getScanResults();
            wifiList = new String[wifiScanList.size()];
            for(int i = 0; i < wifiScanList.size(); i++){
                wifiList[i] = ((wifiScanList.get(i)).SSID);
            }
            String filtered[] = new String[wifiScanList.size()];
            int counter = 0;
            for (String eachWifi : wifiList) {
                String[] temp = eachWifi.split(",");

                filtered[counter] = temp[0].substring(5).trim();//+"\n" + temp[2].substring(12).trim()+"\n" +temp[3].substring(6).trim();//0->SSID, 2->Key Management 3-> Strength

                counter++;

            }
            list.setAdapter(new ArrayAdapter<String>(getApplicationContext(),R.layout.list_item,R.id.label, filtered));


        }
    }

    private void finallyConnect(String networkPass, String networkSSID) {
        WifiConfiguration wifiConfig = new WifiConfiguration();
        wifiConfig.SSID = String.format("\"%s\"", networkSSID);
        wifiConfig.preSharedKey = String.format("\"%s\"", networkPass);

        // remember id
        int netId = mainWifiObj.addNetwork(wifiConfig);
        mainWifiObj.disconnect();
        mainWifiObj.enableNetwork(netId, true);
        mainWifiObj.reconnect();

        WifiConfiguration conf = new WifiConfiguration();
        conf.SSID = "\"\"" + networkSSID + "\"\"";
        conf.preSharedKey = "\"" + networkPass + "\"";
        mainWifiObj.addNetwork(conf);
    }

    private void connectToWifi(final String wifiSSID) {
        final Dialog dialog = new Dialog(this);
        dialog.setContentView(R.layout.connect);
        dialog.setTitle("Connect to Network");
        TextView textSSID = (TextView) dialog.findViewById(R.id.textSSID1);

        Button dialogButton = (Button) dialog.findViewById(R.id.okButton);
        pass = (EditText) dialog.findViewById(R.id.textPassword);
        textSSID.setText(wifiSSID);

        // if button is clicked, connect to the network;
        dialogButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String checkPassword = pass.getText().toString();
                finallyConnect(checkPassword, wifiSSID);
                dialog.dismiss();
            }
        });
        dialog.show();
    }

}

By debugging the code I found that the wifilist doesn't contain a single value even after getScanResults is called. I've even tried to find codes shown in various threads and none of those seem to list the wifi networks. How can I make this code work?

Answer 1

From Android 6.0 onwards, you also need location permissions to get the wifi scanResult. Refer the documentation.