settings/wifi/WifiSettings.java

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.settings.wifi;

import static android.net.wifi.WifiConfiguration.INVALID_NETWORK_ID;

import android.app.ActionBar;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.NetworkInfo.DetailedState;
import android.net.wifi.ScanResult;
import android.net.wifi.SupplicantState;
import android.net.wifi.WifiConfiguration;
import android.net.wifi.WifiConfiguration.KeyMgmt;
import android.net.wifi.WifiInfo;
import android.net.wifi.WifiManager;
import android.net.wifi.WpsResult;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.preference.Preference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceScreen;
import android.security.Credentials;
import android.security.KeyStore;
import android.util.Log;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Gravity;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView.AdapterContextMenuInfo;
import android.widget.Switch;
import android.widget.TextView;
import android.widget.Toast;

import com.android.internal.util.AsyncChannel;
import com.android.settings.R;
import com.android.settings.SettingsPreferenceFragment;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.concurrent.atomic.AtomicBoolean;

/**
 * This currently provides three types of UI.
 *
 * Two are for phones with relatively small screens: "for SetupWizard" and "for usual Settings".
 * Users just need to launch WifiSettings Activity as usual. The request will be appropriately
 * handled by ActivityManager, and they will have appropriate look-and-feel with this fragment.
 *
 * Third type is for Setup Wizard with X-Large, landscape UI. Users need to launch
 * {@link WifiSettingsForSetupWizardXL} Activity, which contains this fragment but also has
 * other decorations specific to that screen.
 */
public class WifiSettings extends SettingsPreferenceFragment
        implements DialogInterface.OnClickListener  {
    private static final String TAG = "WifiSettings";
    private static final int MENU_ID_SCAN = Menu.FIRST;
    private static final int MENU_ID_ADD_NETWORK = Menu.FIRST + 1;
    private static final int MENU_ID_ADVANCED = Menu.FIRST + 2;
    private static final int MENU_ID_CONNECT = Menu.FIRST + 3;
    private static final int MENU_ID_FORGET = Menu.FIRST + 4;
    private static final int MENU_ID_MODIFY = Menu.FIRST + 5;

    private static final int WIFI_DIALOG_ID = 1;

    // Combo scans can take 5-6s to complete - set to 10s.
    private static final int WIFI_RESCAN_INTERVAL_MS = 10 * 1000;

    // Instance state keys
    private static final String SAVE_DIALOG_EDIT_MODE = "edit_mode";
    private static final String SAVE_DIALOG_ACCESS_POINT_STATE = "wifi_ap_state";

    private final IntentFilter mFilter;
    private final BroadcastReceiver mReceiver;
    private final Scanner mScanner;

    private WifiManager mWifiManager;
    private WifiEnabler mWifiEnabler;
    // An access point being editted is stored here.
    private AccessPoint mSelectedAccessPoint;

    private DetailedState mLastState;
    private WifiInfo mLastInfo;

    private AtomicBoolean mConnected = new AtomicBoolean(false);

    private int mKeyStoreNetworkId = INVALID_NETWORK_ID;

    private WifiDialog mDialog;

    private TextView mEmptyView;

    /* Used in Wifi Setup context */

    // this boolean extra specifies whether to disable the Next button when not connected
    private static final String EXTRA_ENABLE_NEXT_ON_CONNECT = "wifi_enable_next_on_connect";

    // should Next button only be enabled when we have a connection?
    private boolean mEnableNextOnConnection;
    private boolean mInXlSetupWizard;

    // Save the dialog details
    private boolean mDlgEdit;
    private AccessPoint mDlgAccessPoint;
    private Bundle mAccessPointSavedState;

    /* End of "used in Wifi Setup context" */

    public WifiSettings() {
        mFilter = new IntentFilter();
        mFilter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);
        mFilter.addAction(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
        mFilter.addAction(WifiManager.NETWORK_IDS_CHANGED_ACTION);
        mFilter.addAction(WifiManager.SUPPLICANT_STATE_CHANGED_ACTION);
        mFilter.addAction(WifiManager.CONFIGURED_NETWORKS_CHANGED_ACTION);
        mFilter.addAction(WifiManager.LINK_CONFIGURATION_CHANGED_ACTION);
        mFilter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION);
        mFilter.addAction(WifiManager.RSSI_CHANGED_ACTION);
        mFilter.addAction(WifiManager.ERROR_ACTION);

        mReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                handleEvent(context, intent);
            }
        };

        mScanner = new Scanner();
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);

        mInXlSetupWizard = (activity instanceof WifiSettingsForSetupWizardXL);
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        // We don't call super.onActivityCreated() here, since it assumes we already set up
        // Preference (probably in onCreate()), while WifiSettings exceptionally set it up in
        // this method.

        mWifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        mWifiManager.asyncConnect(getActivity(), new WifiServiceHandler());
        if (savedInstanceState != null
                && savedInstanceState.containsKey(SAVE_DIALOG_ACCESS_POINT_STATE)) {
            mDlgEdit = savedInstanceState.getBoolean(SAVE_DIALOG_EDIT_MODE);
            mAccessPointSavedState = savedInstanceState.getBundle(SAVE_DIALOG_ACCESS_POINT_STATE);
        }

        final Activity activity = getActivity();
        final Intent intent = activity.getIntent();

        // if we're supposed to enable/disable the Next button based on our current connection
        // state, start it off in the right state
        mEnableNextOnConnection = intent.getBooleanExtra(EXTRA_ENABLE_NEXT_ON_CONNECT, false);

        if (mEnableNextOnConnection) {
            if (hasNextButton()) {
                final ConnectivityManager connectivity = (ConnectivityManager)
                        getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
                if (connectivity != null) {
                    NetworkInfo info = connectivity.getNetworkInfo(
                            ConnectivityManager.TYPE_WIFI);
                    changeNextButtonState(info.isConnected());
                }
            }
        }

        if (mInXlSetupWizard) {
            addPreferencesFromResource(R.xml.wifi_access_points_for_wifi_setup_xl);
        } else {
            addPreferencesFromResource(R.xml.wifi_settings);

            Switch actionBarSwitch = new Switch(activity);

            if (activity instanceof PreferenceActivity) {
                PreferenceActivity preferenceActivity = (PreferenceActivity) activity;
                if (preferenceActivity.onIsHidingHeaders() || !preferenceActivity.onIsMultiPane()) {
                    final int padding = activity.getResources().getDimensionPixelSize(
                            R.dimen.action_bar_switch_padding);
                    actionBarSwitch.setPadding(0, 0, padding, 0);
                    activity.getActionBar().setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM,
                            ActionBar.DISPLAY_SHOW_CUSTOM);
                    activity.getActionBar().setCustomView(actionBarSwitch, new ActionBar.LayoutParams(
                            ActionBar.LayoutParams.WRAP_CONTENT,
                            ActionBar.LayoutParams.WRAP_CONTENT,
                            Gravity.CENTER_VERTICAL | Gravity.RIGHT));
                }
            }

            mWifiEnabler = new WifiEnabler(activity, actionBarSwitch);
        }

        mEmptyView = (TextView) getView().findViewById(android.R.id.empty);
        getListView().setEmptyView(mEmptyView);

        registerForContextMenu(getListView());
        setHasOptionsMenu(true);

        // After confirming PreferenceScreen is available, we call super.
        super.onActivityCreated(savedInstanceState);
    }

    @Override
    public void onResume() {
        super.onResume();
        if (mWifiEnabler != null) {
            mWifiEnabler.resume();
        }

        getActivity().registerReceiver(mReceiver, mFilter);
        if (mKeyStoreNetworkId != INVALID_NETWORK_ID &&
                KeyStore.getInstance().state() == KeyStore.State.UNLOCKED) {
            mWifiManager.connectNetwork(mKeyStoreNetworkId);
        }
        mKeyStoreNetworkId = INVALID_NETWORK_ID;

        updateAccessPoints();
    }

    @Override
    public void onPause() {
        super.onPause();
        if (mWifiEnabler != null) {
            mWifiEnabler.pause();
        }
        getActivity().unregisterReceiver(mReceiver);
        mScanner.pause();
    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        // We don't want menus in Setup Wizard XL.
        if (!mInXlSetupWizard) {
            final boolean wifiIsEnabled = mWifiManager.isWifiEnabled();
            menu.add(Menu.NONE, MENU_ID_SCAN, 0, R.string.wifi_menu_scan)
                    //.setIcon(R.drawable.ic_menu_scan_network)
                    .setEnabled(wifiIsEnabled)
                    .setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
            menu.add(Menu.NONE, MENU_ID_ADD_NETWORK, 0, R.string.wifi_add_network)
                    .setEnabled(wifiIsEnabled)
                    .setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
            menu.add(Menu.NONE, MENU_ID_ADVANCED, 0, R.string.wifi_menu_advanced)
                    //.setIcon(android.R.drawable.ic_menu_manage)
                    .setShowAsAction(MenuItem.SHOW_AS_ACTION_NEVER);
        }
        super.onCreateOptionsMenu(menu, inflater);
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);

        // If the dialog is showing, save its state.
        if (mDialog != null && mDialog.isShowing()) {
            outState.putBoolean(SAVE_DIALOG_EDIT_MODE, mDlgEdit);
            if (mDlgAccessPoint != null) {
                mAccessPointSavedState = new Bundle();
                mDlgAccessPoint.saveWifiState(mAccessPointSavedState);
                outState.putBundle(SAVE_DIALOG_ACCESS_POINT_STATE, mAccessPointSavedState);
            }
        }
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case MENU_ID_SCAN:
                if (mWifiManager.isWifiEnabled()) {
                    mScanner.forceScan();
                }
                return true;
            case MENU_ID_ADD_NETWORK:
                if (mWifiManager.isWifiEnabled()) {
                    onAddNetworkPressed();
                }
                return true;
            case MENU_ID_ADVANCED:
                if (getActivity() instanceof PreferenceActivity) {
                    ((PreferenceActivity) getActivity()).startPreferencePanel(
                            AdvancedWifiSettings.class.getCanonicalName(),
                            null,
                            R.string.wifi_advanced_titlebar, null,
                            this, 0);
                } else {
                    startFragment(this, AdvancedWifiSettings.class.getCanonicalName(), -1, null);
                }
                return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View view, ContextMenuInfo info) {
        if (mInXlSetupWizard) {
            ((WifiSettingsForSetupWizardXL)getActivity()).onCreateContextMenu(menu, view, info);
        } else if (info instanceof AdapterContextMenuInfo) {
            Preference preference = (Preference) getListView().getItemAtPosition(
                    ((AdapterContextMenuInfo) info).position);

            if (preference instanceof AccessPoint) {
                mSelectedAccessPoint = (AccessPoint) preference;
                menu.setHeaderTitle(mSelectedAccessPoint.ssid);
                if (mSelectedAccessPoint.getLevel() != -1
                        && mSelectedAccessPoint.getState() == null) {
                    menu.add(Menu.NONE, MENU_ID_CONNECT, 0, R.string.wifi_menu_connect);
                }
                if (mSelectedAccessPoint.networkId != INVALID_NETWORK_ID) {
                    menu.add(Menu.NONE, MENU_ID_FORGET, 0, R.string.wifi_menu_forget);
                    menu.add(Menu.NONE, MENU_ID_MODIFY, 0, R.string.wifi_menu_modify);
                }
            }
        }
    }

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        if (mSelectedAccessPoint == null) {
            return super.onContextItemSelected(item);
        }
        switch (item.getItemId()) {
            case MENU_ID_CONNECT: {
                if (mSelectedAccessPoint.networkId != INVALID_NETWORK_ID) {
                    if (!requireKeyStore(mSelectedAccessPoint.getConfig())) {
                        mWifiManager.connectNetwork(mSelectedAccessPoint.networkId);
                    }
                } else if (mSelectedAccessPoint.security == AccessPoint.SECURITY_NONE) {
                    /** Bypass dialog for unsecured networks */
                    mSelectedAccessPoint.generateOpenNetworkConfig();
                    mWifiManager.connectNetwork(mSelectedAccessPoint.getConfig());
                } else {
                    showConfigUi(mSelectedAccessPoint, true);
                }
                return true;
            }
            case MENU_ID_FORGET: {
                mWifiManager.forgetNetwork(mSelectedAccessPoint.networkId);
                return true;
            }
            case MENU_ID_MODIFY: {
                showConfigUi(mSelectedAccessPoint, true);
                return true;
            }
        }
        return super.onContextItemSelected(item);
    }

    @Override
    public boolean onPreferenceTreeClick(PreferenceScreen screen, Preference preference) {
        if (preference instanceof AccessPoint) {
            mSelectedAccessPoint = (AccessPoint) preference;
            /** Bypass dialog for unsecured, unsaved networks */
            if (mSelectedAccessPoint.security == AccessPoint.SECURITY_NONE &&
                    mSelectedAccessPoint.networkId == INVALID_NETWORK_ID) {
                mSelectedAccessPoint.generateOpenNetworkConfig();
                mWifiManager.connectNetwork(mSelectedAccessPoint.getConfig());
            } else {
                showConfigUi(mSelectedAccessPoint, false);
            }
        } else {
            return super.onPreferenceTreeClick(screen, preference);
        }
        return true;
    }

    /**
     * Shows an appropriate Wifi configuration component.
     * Called when a user clicks "Add network" preference or one of available networks is selected.
     */
    private void showConfigUi(AccessPoint accessPoint, boolean edit) {
        if (mInXlSetupWizard) {
            ((WifiSettingsForSetupWizardXL)getActivity()).showConfigUi(accessPoint, edit);
        } else {
            showDialog(accessPoint, edit);
        }
    }

    private void showDialog(AccessPoint accessPoint, boolean edit) {
        if (mDialog != null) {
            removeDialog(WIFI_DIALOG_ID);
            mDialog = null;
        }

        // Save the access point and edit mode
        mDlgAccessPoint = accessPoint;
        mDlgEdit = edit;

        showDialog(WIFI_DIALOG_ID);
    }

    @Override
    public Dialog onCreateDialog(int dialogId) {
        AccessPoint ap = mDlgAccessPoint; // For manual launch
        if (ap == null) { // For re-launch from saved state
            if (mAccessPointSavedState != null) {
                ap = new AccessPoint(getActivity(), mAccessPointSavedState);
                // For repeated orientation changes
                mDlgAccessPoint = ap;
            }
        }
        // If it's still null, fine, it's for Add Network
        mSelectedAccessPoint = ap;
        mDialog = new WifiDialog(getActivity(), this, ap, mDlgEdit);
        return mDialog;
    }

    private boolean requireKeyStore(WifiConfiguration config) {
        if (WifiConfigController.requireKeyStore(config) &&
                KeyStore.getInstance().state() != KeyStore.State.UNLOCKED) {
            mKeyStoreNetworkId = config.networkId;
            Credentials.getInstance().unlock(getActivity());
            return true;
        }
        return false;
    }

    /**
     * Shows the latest access points available with supplimental information like
     * the strength of network and the security for it.
     */
    private void updateAccessPoints() {
        final int wifiState = mWifiManager.getWifiState();

        switch (wifiState) {
            case WifiManager.WIFI_STATE_ENABLED:
                // AccessPoints are automatically sorted with TreeSet.
                final Collection<AccessPoint> accessPoints = constructAccessPoints();
                getPreferenceScreen().removeAll();
                if (mInXlSetupWizard) {
                    ((WifiSettingsForSetupWizardXL)getActivity()).onAccessPointsUpdated(
                            getPreferenceScreen(), accessPoints);
                } else {
                    for (AccessPoint accessPoint : accessPoints) {
                        getPreferenceScreen().addPreference(accessPoint);
                    }
                }
                break;

            case WifiManager.WIFI_STATE_ENABLING:
                getPreferenceScreen().removeAll();
                break;

            case WifiManager.WIFI_STATE_DISABLING:
                addMessagePreference(R.string.wifi_stopping);
                break;

            case WifiManager.WIFI_STATE_DISABLED:
                addMessagePreference(R.string.wifi_empty_list_wifi_off);
                break;
        }
    }

    private void addMessagePreference(int messageId) {
        if (mEmptyView != null) mEmptyView.setText(messageId);
        getPreferenceScreen().removeAll();
    }

    /** Returns sorted list of access points */
    private List<AccessPoint> constructAccessPoints() {
        ArrayList<AccessPoint> accessPoints = new ArrayList<AccessPoint>();
        /** Lookup table to more quickly update AccessPoints by only considering objects with the
         * correct SSID.  Maps SSID -> List of AccessPoints with the given SSID.  */
        Multimap<String, AccessPoint> apMap = new Multimap<String, AccessPoint>();

        final List<WifiConfiguration> configs = mWifiManager.getConfiguredNetworks();
        if (configs != null) {
            for (WifiConfiguration config : configs) {
                AccessPoint accessPoint = new AccessPoint(getActivity(), config);
                accessPoint.update(mLastInfo, mLastState);
                accessPoints.add(accessPoint);
                apMap.put(accessPoint.ssid, accessPoint);
            }
        }

        final List<ScanResult> results = mWifiManager.getScanResults();
        if (results != null) {
            for (ScanResult result : results) {
                // Ignore hidden and ad-hoc networks.
                if (result.SSID == null || result.SSID.length() == 0 ||
                        result.capabilities.contains("[IBSS]")) {
                    continue;
                }

                boolean found = false;
                for (AccessPoint accessPoint : apMap.getAll(result.SSID)) {
                    if (accessPoint.update(result))
                        found = true;
                }
                if (!found) {
                    AccessPoint accessPoint = new AccessPoint(getActivity(), result);
                    accessPoints.add(accessPoint);
                    apMap.put(accessPoint.ssid, accessPoint);
                }
            }
        }

        // Pre-sort accessPoints to speed preference insertion
        Collections.sort(accessPoints);
        return accessPoints;
    }

    /** A restricted multimap for use in constructAccessPoints */
    private class Multimap<K,V> {
        private HashMap<K,List<V>> store = new HashMap<K,List<V>>();
        /** retrieve a non-null list of values with key K */
        List<V> getAll(K key) {
            List<V> values = store.get(key);
            return values != null ? values : Collections.<V>emptyList();
        }

        void put(K key, V val) {
            List<V> curVals = store.get(key);
            if (curVals == null) {
                curVals = new ArrayList<V>(3);
                store.put(key, curVals);
            }
            curVals.add(val);
        }
    }

    private void handleEvent(Context context, Intent intent) {
        String action = intent.getAction();
        if (WifiManager.WIFI_STATE_CHANGED_ACTION.equals(action)) {
            updateWifiState(intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE,
                    WifiManager.WIFI_STATE_UNKNOWN));
        } else if (WifiManager.SCAN_RESULTS_AVAILABLE_ACTION.equals(action) ||
                WifiManager.CONFIGURED_NETWORKS_CHANGED_ACTION.equals(action) ||
                WifiManager.LINK_CONFIGURATION_CHANGED_ACTION.equals(action)) {
                updateAccessPoints();
        } else if (WifiManager.SUPPLICANT_STATE_CHANGED_ACTION.equals(action)) {
            //Ignore supplicant state changes when network is connected
            //TODO: we should deprecate SUPPLICANT_STATE_CHANGED_ACTION and
            //introduce a broadcast that combines the supplicant and network
            //network state change events so the apps dont have to worry about
            //ignoring supplicant state change when network is connected
            //to get more fine grained information.
            if (!mConnected.get()) {
                updateConnectionState(WifiInfo.getDetailedStateOf((SupplicantState)
                        intent.getParcelableExtra(WifiManager.EXTRA_NEW_STATE)));
            }

            if (mInXlSetupWizard) {
                ((WifiSettingsForSetupWizardXL)getActivity()).onSupplicantStateChanged(intent);
            }
        } else if (WifiManager.NETWORK_STATE_CHANGED_ACTION.equals(action)) {
            NetworkInfo info = (NetworkInfo) intent.getParcelableExtra(
                    WifiManager.EXTRA_NETWORK_INFO);
            mConnected.set(info.isConnected());
            changeNextButtonState(info.isConnected());
            updateAccessPoints();
            updateConnectionState(info.getDetailedState());
        } else if (WifiManager.RSSI_CHANGED_ACTION.equals(action)) {
            updateConnectionState(null);
        } else if (WifiManager.ERROR_ACTION.equals(action)) {
            int errorCode = intent.getIntExtra(WifiManager.EXTRA_ERROR_CODE, 0);
            switch (errorCode) {
                case WifiManager.WPS_OVERLAP_ERROR:
                    Toast.makeText(context, R.string.wifi_wps_overlap_error,
                            Toast.LENGTH_SHORT).show();
                    break;
            }
        }
    }

    private void updateConnectionState(DetailedState state) {
        /* sticky broadcasts can call this when wifi is disabled */
        if (!mWifiManager.isWifiEnabled()) {
            mScanner.pause();
            return;
        }

        if (state == DetailedState.OBTAINING_IPADDR) {
            mScanner.pause();
        } else {
            mScanner.resume();
        }

        mLastInfo = mWifiManager.getConnectionInfo();
        if (state != null) {
            mLastState = state;
        }

        for (int i = getPreferenceScreen().getPreferenceCount() - 1; i >= 0; --i) {
            // Maybe there's a WifiConfigPreference
            Preference preference = getPreferenceScreen().getPreference(i);
            if (preference instanceof AccessPoint) {
                final AccessPoint accessPoint = (AccessPoint) preference;
                accessPoint.update(mLastInfo, mLastState);
            }
        }

        if (mInXlSetupWizard) {
            ((WifiSettingsForSetupWizardXL)getActivity()).updateConnectionState(mLastState);
        }
    }

    private void updateWifiState(int state) {
        getActivity().invalidateOptionsMenu();

        switch (state) {
            case WifiManager.WIFI_STATE_ENABLED:
                mScanner.resume();
                return; // not break, to avoid the call to pause() below

            case WifiManager.WIFI_STATE_ENABLING:
                addMessagePreference(R.string.wifi_starting);
                break;

            case WifiManager.WIFI_STATE_DISABLED:
                addMessagePreference(R.string.wifi_empty_list_wifi_off);
                break;
        }

        mLastInfo = null;
        mLastState = null;
        mScanner.pause();
    }

    private class Scanner extends Handler {
        private int mRetry = 0;

        void resume() {
            if (!hasMessages(0)) {
                sendEmptyMessage(0);
            }
        }

        void forceScan() {
            removeMessages(0);
            sendEmptyMessage(0);
        }

        void pause() {
            mRetry = 0;
            removeMessages(0);
        }

        @Override
        public void handleMessage(Message message) {
            if (mWifiManager.startScanActive()) {
                mRetry = 0;
            } else if (++mRetry >= 3) {
                mRetry = 0;
                Toast.makeText(getActivity(), R.string.wifi_fail_to_scan,
                        Toast.LENGTH_LONG).show();
                return;
            }
            sendEmptyMessageDelayed(0, WIFI_RESCAN_INTERVAL_MS);
        }
    }

    private class WifiServiceHandler extends Handler {

        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case AsyncChannel.CMD_CHANNEL_HALF_CONNECTED:
                    if (msg.arg1 == AsyncChannel.STATUS_SUCCESSFUL) {
                        //AsyncChannel in msg.obj
                    } else {
                        //AsyncChannel set up failure, ignore
                        Log.e(TAG, "Failed to establish AsyncChannel connection");
                    }
                    break;
                case WifiManager.CMD_WPS_COMPLETED:
                    WpsResult result = (WpsResult) msg.obj;
                    if (result == null) break;
                    AlertDialog.Builder dialog = new AlertDialog.Builder(getActivity())
                        .setTitle(R.string.wifi_wps_setup_title)
                        .setPositiveButton(android.R.string.ok, null);
                    switch (result.status) {
                        case FAILURE:
                            dialog.setMessage(R.string.wifi_wps_failed);
                            dialog.show();
                            break;
                        case IN_PROGRESS:
                            dialog.setMessage(R.string.wifi_wps_in_progress);
                            dialog.show();
                            break;
                        default:
                            if (result.pin != null) {
                                dialog.setMessage(getResources().getString(
                                        R.string.wifi_wps_pin_output, result.pin));
                                dialog.show();
                            }
                            break;
                    }
                    break;
                //TODO: more connectivity feedback
                default:
                    //Ignore
                    break;
            }
        }
    }

    /**
     * Renames/replaces "Next" button when appropriate. "Next" button usually exists in
     * Wifi setup screens, not in usual wifi settings screen.
     *
     * @param connected true when the device is connected to a wifi network.
     */
    private void changeNextButtonState(boolean connected) {
        if (mInXlSetupWizard) {
            ((WifiSettingsForSetupWizardXL)getActivity()).changeNextButtonState(connected);
        } else if (mEnableNextOnConnection && hasNextButton()) {
            getNextButton().setEnabled(connected);
        }
    }

    public void onClick(DialogInterface dialogInterface, int button) {
        if (mInXlSetupWizard) {
            if (button == WifiDialog.BUTTON_FORGET && mSelectedAccessPoint != null) {
                forget();
            } else if (button == WifiDialog.BUTTON_SUBMIT) {
                ((WifiSettingsForSetupWizardXL)getActivity()).onConnectButtonPressed();
            }
        } else {
            if (button == WifiDialog.BUTTON_FORGET && mSelectedAccessPoint != null) {
                forget();
            } else if (button == WifiDialog.BUTTON_SUBMIT) {
                submit(mDialog.getController());
            }
        }

    }

    /* package */ void submit(WifiConfigController configController) {
        int networkSetup = configController.chosenNetworkSetupMethod();
        switch(networkSetup) {
            case WifiConfigController.WPS_PBC:
            case WifiConfigController.WPS_DISPLAY:
            case WifiConfigController.WPS_KEYPAD:
                mWifiManager.startWps(configController.getWpsConfig());
                break;
            case WifiConfigController.MANUAL:
                final WifiConfiguration config = configController.getConfig();

                if (config == null) {
                    if (mSelectedAccessPoint != null
                            && !requireKeyStore(mSelectedAccessPoint.getConfig())
                            && mSelectedAccessPoint.networkId != INVALID_NETWORK_ID) {
                        mWifiManager.connectNetwork(mSelectedAccessPoint.networkId);
                    }
                } else if (config.networkId != INVALID_NETWORK_ID) {
                    if (mSelectedAccessPoint != null) {
                        saveNetwork(config);
                    }
                } else {
                    if (configController.isEdit() || requireKeyStore(config)) {
                        saveNetwork(config);
                    } else {
                        mWifiManager.connectNetwork(config);
                    }
                }
                break;
        }

        if (mWifiManager.isWifiEnabled()) {
            mScanner.resume();
        }
        updateAccessPoints();
    }

    private void saveNetwork(WifiConfiguration config) {
        if (mInXlSetupWizard) {
            ((WifiSettingsForSetupWizardXL)getActivity()).onSaveNetwork(config);
        } else {
            mWifiManager.saveNetwork(config);
        }
    }

    /* package */ void forget() {
        mWifiManager.forgetNetwork(mSelectedAccessPoint.networkId);

        if (mWifiManager.isWifiEnabled()) {
            mScanner.resume();
        }
        updateAccessPoints();

        // We need to rename/replace "Next" button in wifi setup context.
        changeNextButtonState(false);
    }

    /**
     * Refreshes acccess points and ask Wifi module to scan networks again.
     */
    /* package */ void refreshAccessPoints() {
        if (mWifiManager.isWifiEnabled()) {
            mScanner.resume();
        }

        getPreferenceScreen().removeAll();
    }

    /**
     * Called when "add network" button is pressed.
     */
    /* package */ void onAddNetworkPressed() {
        // No exact access point is selected.
        mSelectedAccessPoint = null;
        showConfigUi(null, true);
    }

    /* package */ int getAccessPointsCount() {
        final boolean wifiIsEnabled = mWifiManager.isWifiEnabled();
        if (wifiIsEnabled) {
            return getPreferenceScreen().getPreferenceCount();
        } else {
            return 0;
        }
    }

    /**
     * Requests wifi module to pause wifi scan. May be ignored when the module is disabled.
     */
    /* package */ void pauseWifiScan() {
        if (mWifiManager.isWifiEnabled()) {
            mScanner.pause();
        }
    }

    /**
     * Requests wifi module to resume wifi scan. May be ignored when the module is disabled.
     */
    /* package */ void resumeWifiScan() {
        if (mWifiManager.isWifiEnabled()) {
            mScanner.resume();
        }
    }
}