marshmallow wifi scan and connect not working

Question

I am trying to scan the available wi-fi networks to get a list of networks and select particular network to connect. Its working on Lollipop but not on marshmallow. As per this and this blog there are few changes to be made, but I did not get how to implement those changes.

Currently in marshmallow, app is connecting to only those networks which are created by app. App crashes when I try to connect to other networks.

Here is my Activity code:

import android.Manifest;
import android.annotation.TargetApi;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiConfiguration;
import android.net.wifi.WifiManager;
import android.os.Build;
import android.os.Bundle;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;


public class CustomWifiListAcivity extends AppCompatActivity {

    private TextView mainText;
    private ListView wifiDeviceList;
    private WifiManager mainWifi;
    private CustomWifiListAcivity.WifiReceiver receiverWifi;
    private List<ScanResult> wifiList;
    private StringBuilder sb;
    private String ssid_selected=null;
    private Context context=null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.wifi_list);
        context=getApplicationContext();
        setTitle("Choose Switchbox");
        wifiDeviceList=(ListView)findViewById(R.id.listView);
        mainWifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        if (!mainWifi.isWifiEnabled())
        {
            Toast.makeText(getApplicationContext(), "Turning WiFi ON...", Toast.LENGTH_LONG).show();
            mainWifi.setWifiEnabled(true);
        }

        wifiDeviceList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, final int position, long id) {
                final String ssid = '"' + wifiList.get(position).SSID + '"';
                final String mac = wifiList.get(position).BSSID;
                String pass = "";



                LayoutInflater inflater = LayoutInflater.from(getApplicationContext());
                View promptView = inflater.inflate(R.layout.dialog_wifi, null);

                AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(CustomWifiListAcivity.this);
                alertDialogBuilder.setView(promptView);
                final EditText ssid_et = (EditText) promptView.findViewById(R.id.editText_ssid);
                final EditText pass_et = (EditText) promptView.findViewById(R.id.editText_pswd);
                ssid_et.setText(wifiList.get(position).SSID);
                alertDialogBuilder
                        .setCancelable(true)
                        .setPositiveButton("Connect", new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int id) {
                                String ssid = '"' + wifiList.get(position).SSID + '"';
                                String password = '"' + pass_et.getText().toString() + '"';

                                System.out.println("ssid: "+ssid);
                                System.out.println("password: "+password);
                                connectToHost(getApplicationContext(),ssid,password);

                            }
                        })
                        .setNegativeButton("Cancel",
                                new DialogInterface.OnClickListener() {
                                    public void onClick(DialogInterface dialog, int id) {
                                        dialog.cancel();
                                    }
                                })
                        .create()
                        .show();
            }
        });
    }
    public void connectToHost(Context context,String host,String password){
        mainWifi  = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
        WifiConfiguration wc=new WifiConfiguration();
        wc.SSID= host;
        wc.preSharedKey =  password;;
        wc.status = WifiConfiguration.Status.ENABLED;
        wc.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.OPEN);
        wc.allowedProtocols.set(WifiConfiguration.Protocol.WPA); // For WPA
        wc.allowedProtocols.set(WifiConfiguration.Protocol.RSN); // For WPA2
        wc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK);
        wc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_EAP);
        wc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);
        wc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);
        wc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);
        wc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);


        int netId=mainWifi.addNetwork(wc);

        try {
            mainWifi.enableNetwork(netId, true);
            mainWifi.setWifiEnabled(true);
            System.out.println("enabled network");
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println(e.getMessage());
        }
    }

    class WifiReceiver extends BroadcastReceiver {
        public void onReceive(Context c, Intent intent) {
            String action = intent.getAction();
            if(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION.equals(action)){
                sb = new StringBuilder();
                wifiList = mainWifi.getScanResults();
                sb.append("\n        Number Of Wifi connections :"+wifiList.size()+"\n\n");

                ArrayList<String> deviceList = new ArrayList<String>();
                for(int i = 0; i < wifiList.size(); i++){
                    sb.append(new Integer(i+1).toString() + ". ");
                    sb.append((wifiList.get(i)).toString());
                    sb.append("\n\n");
                    deviceList.add(wifiList.get(i).SSID);
                }


                ArrayAdapter arrayAdapter = new ArrayAdapter(CustomWifiListAcivity.this,
                        android.R.layout.simple_list_item_1, deviceList.toArray());
                wifiDeviceList.setAdapter(arrayAdapter);
            }

        }

    }

    @Override
    protected void onPause() {
        super.onPause();
        unregisterReceiver(receiverWifi);
    }

    @Override
    protected void onPostResume() {
        super.onPostResume();
        receiverWifi = new CustomWifiListAcivity.WifiReceiver();
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
        registerReceiver(receiverWifi, intentFilter);
        getWifi();
    }
    private void getWifi() {

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            Toast.makeText(CustomWifiListAcivity.this, "version>=marshmallow", Toast.LENGTH_SHORT).show();


            if (checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                Toast.makeText(CustomWifiListAcivity.this, "location turned off", Toast.LENGTH_SHORT).show();
                requestPermissions(new String[]{Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION}, 1);
            }
            else{

                Toast.makeText(CustomWifiListAcivity.this, "location turned on", Toast.LENGTH_SHORT).show();
                mainWifi.startScan();
            }
        }else {

            Toast.makeText(CustomWifiListAcivity.this, "scanning", Toast.LENGTH_SHORT).show();
            mainWifi.startScan();
        }
    }
    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {

        if (requestCode == 1) {

            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                Toast.makeText(CustomWifiListAcivity.this, "permission granted", Toast.LENGTH_SHORT).show();  mainWifi.startScan();
            }else{
                Toast.makeText(CustomWifiListAcivity.this, "permission not granted", Toast.LENGTH_SHORT).show();
                return;
            }


        }
    }
}

here are permissions from manifest file

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

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

Answer 1

I have managed to solve the issue. Following code works on marshmallow. reconfiguration of previously configured network is not allowed in marshmallow.

import android.Manifest;
import android.annotation.TargetApi;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiConfiguration;
import android.net.wifi.WifiManager;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;


public class CustomWifiListAcivity extends AppCompatActivity {

    private TextView mainText;
    private ListView wifiDeviceList;
    private WifiManager mainWifi;
    private CustomWifiListAcivity.WifiReceiver receiverWifi;
    private List<ScanResult> wifiList;
    private StringBuilder sb;
    private String ssid_selected=null;
    private Context context=null;

    private static final int MY_PERMISSIONS_REQUEST =1 ;

    Button connect_btn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.wifi_list);
        context=getApplicationContext();
        setTitle("Choose Switchbox");
        connect_btn=(Button) findViewById(R.id.connect_btn);

        wifiDeviceList=(ListView)findViewById(R.id.listView);
        mainWifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        if (!mainWifi.isWifiEnabled())
        {
            Toast.makeText(getApplicationContext(), "Turning WiFi ON...", Toast.LENGTH_LONG).show();
            mainWifi.setWifiEnabled(true);
        }

       wifiDeviceList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, final int position, long id) {
                final String ssid = '"' + wifiList.get(position).SSID + '"';
                final String mac = wifiList.get(position).BSSID;
                String pass = "";


                LayoutInflater inflater = LayoutInflater.from(getApplicationContext());
                View promptView = inflater.inflate(R.layout.dialog_wifi, null);

                AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(CustomWifiListAcivity.this);
                alertDialogBuilder.setView(promptView);
                final EditText ssid_et = (EditText) promptView.findViewById(R.id.editText_ssid);
                final EditText pass_et = (EditText) promptView.findViewById(R.id.editText_pswd);
                ssid_et.setText(wifiList.get(position).SSID);
                alertDialogBuilder
                        .setCancelable(true)
                        .setPositiveButton("Connect", new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int id) {
                                String ssid = '"' + wifiList.get(position).SSID + '"';
                                String password = '"' + pass_et.getText().toString() + '"';

                                System.out.println("ssid: "+ssid);
                                System.out.println("password: "+password);

                                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                                    connectToHost(getApplicationContext(), ssid, password);
                                }
                                else{
                                    connectToHost2(getApplicationContext(), ssid, password);
                                }

                            }
                        })
                        .setNegativeButton("Cancel",
                                new DialogInterface.OnClickListener() {
                                    public void onClick(DialogInterface dialog, int id) {
                                        dialog.cancel();
                                    }
                                })
                        .create()
                        .show();
            }
        });

    }



    public void connectToHost(Context context,String host,String password){
        mainWifi  = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
        WifiConfiguration wc=new WifiConfiguration();

        wc.SSID= host;
        wc.preSharedKey =  password;

        int netId=mainWifi.addNetwork(wc);


        try {
            mainWifi.enableNetwork(netId, true);
            mainWifi.setWifiEnabled(true);

            System.out.println("enabled network");
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println(e.getMessage());
        }
    }


    public void connectToHost2(Context context,String host,String password){
        mainWifi  = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
        WifiConfiguration wc=new WifiConfiguration();

        wc.SSID= host;
        wc.preSharedKey =  password;
            wc.status = WifiConfiguration.Status.ENABLED;
            wc.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.OPEN);
            wc.allowedProtocols.set(WifiConfiguration.Protocol.WPA); // For WPA
            wc.allowedProtocols.set(WifiConfiguration.Protocol.RSN); // For WPA2
            wc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK);
            wc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_EAP);
            wc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);
            wc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);
            wc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);
            wc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);


        int netId=mainWifi.addNetwork(wc);


        try {
            mainWifi.enableNetwork(netId, true);
            mainWifi.setWifiEnabled(true);

            System.out.println("enabled network");
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println(e.getMessage());
        }
    }
    class WifiReceiver extends BroadcastReceiver {
        public void onReceive(Context c, Intent intent) {
            String action = intent.getAction();
            if(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION.equals(action)){
                sb = new StringBuilder();
                wifiList = mainWifi.getScanResults();
                sb.append("\n Number Of Wifi connections :"+wifiList.size()+"\n\n");

                ArrayList<String> deviceList = new ArrayList<String>();
                for(int i = 0; i < wifiList.size(); i++){
                    sb.append(new Integer(i+1).toString() + ". ");
                    sb.append((wifiList.get(i)).toString());
                    sb.append("\n\n");
                    deviceList.add(wifiList.get(i).SSID);
                }

                ArrayAdapter arrayAdapter = new ArrayAdapter(CustomWifiListAcivity.this,
                        android.R.layout.simple_list_item_1, deviceList.toArray());

                wifiDeviceList.setAdapter(arrayAdapter);
            }

        }

    }



    @Override
    protected void onPause() {
        super.onPause();
        unregisterReceiver(receiverWifi);
    }

    @Override
    protected void onPostResume() {
        super.onPostResume();
        receiverWifi = new CustomWifiListAcivity.WifiReceiver();
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
        registerReceiver(receiverWifi, intentFilter);
        getWifi();
    }
    private void getWifi() {

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            Toast.makeText(CustomWifiListAcivity.this, "version>=marshmallow", Toast.LENGTH_SHORT).show();

            if (ContextCompat.checkSelfPermission(CustomWifiListAcivity.this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                Toast.makeText(CustomWifiListAcivity.this, "location turned off", Toast.LENGTH_SHORT).show();

                ActivityCompat.requestPermissions(CustomWifiListAcivity.this,new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, MY_PERMISSIONS_REQUEST);

            }

            else{
                Toast.makeText(CustomWifiListAcivity.this, "location turned on", Toast.LENGTH_SHORT).show();
                mainWifi.startScan();
            }

        }else {

            Toast.makeText(CustomWifiListAcivity.this, "scanning", Toast.LENGTH_SHORT).show();
            mainWifi.startScan();
        }
    }


    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {

        if (requestCode == MY_PERMISSIONS_REQUEST) {

            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                Toast.makeText(CustomWifiListAcivity.this, "permission granted", Toast.LENGTH_SHORT).show();
                mainWifi.startScan();

            }else{
                Toast.makeText(CustomWifiListAcivity.this, "permission not granted", Toast.LENGTH_SHORT).show();
                return;
            }

        }
    }
}

connectToHost() method is for marshmallow. connectToHost2() method is for devices below marshmallow.