uk.ac.horizon.ubihelper.service.channel.WifiScannerChannel.java Source code

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Here is the source code for uk.ac.horizon.ubihelper.service.channel.WifiScannerChannel.java

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/**
 * Copyright (c) 2012 The University of Nottingham
 * 
 * This file is part of ubihelper
 *
 *  ubihelper is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  ubihelper is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with ubihelper. If not, see <http://www.gnu.org/licenses/>.
 *  
 *  @author Chris Greenhalgh (cmg@cs.nott.ac.uk), The University of Nottingham
 */
package uk.ac.horizon.ubihelper.service.channel;

import java.util.HashMap;
import java.util.List;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiManager;
import android.os.Handler;
import android.util.Log;

/**
 * @author cmg
 *
 */
public class WifiScannerChannel extends PollingChannel {
    private static final String KEY_TIME = "time";
    private static final String KEY_NETWORKS = "networks";
    private static final String KEY_ADDRESS = "address";
    private static final String KEY_CAPABILITIES = "capabilities";
    private static final String KEY_NAME = "name";
    private static final String KEY_LEVEL = "level";

    static String TAG = "ubihelper-wifichan";
    private WifiManager wifi;
    private Service service;

    /**
     * @param handler
     * @param name
     */
    public WifiScannerChannel(Service service, Handler handler, String name) {
        super(handler, name);
        wifi = (WifiManager) service.getSystemService(Service.WIFI_SERVICE);
        this.service = service;
        if (wifi == null)
            Log.w(TAG, "No WifiManager");
        IntentFilter filter = new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
        filter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);
        this.service.registerReceiver(receiver, filter);
    }

    @Override
    public synchronized void close() {
        super.close();
        service.unregisterReceiver(receiver);
    }

    private BroadcastReceiver receiver = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {
            if (WifiManager.SCAN_RESULTS_AVAILABLE_ACTION.equals(intent.getAction())) {
                handlePollComplete();
            } else if (WifiManager.WIFI_STATE_CHANGED_ACTION.equals(intent.getAction())) {
                // turned off?
                if (!wifi.isWifiEnabled())
                    synchronized (WifiScannerChannel.this) {
                        if (pollInProgress)
                            pollComplete();
                    }
            }
        }
    };

    @Override
    protected boolean startPoll() {
        if (wifi == null) {
            return false;
        }
        if (!wifi.isWifiEnabled()) {
            Log.d(TAG, "startPoll: wifi disabled");
            return false;
        }
        if (!wifi.startScan()) {
            Log.d(TAG, "startPoll: could not startScan");
            return false;
        }
        return true;
    }

    protected synchronized void handlePollComplete() {
        if (pollInProgress)
            pollComplete();
        try {
            JSONObject value = new JSONObject();
            value.put(KEY_TIME, System.currentTimeMillis());
            JSONArray ds = new JSONArray();
            value.put(KEY_NETWORKS, ds);
            List<ScanResult> results = wifi.getScanResults();
            for (ScanResult result : results) {
                JSONObject d = new JSONObject();
                if (result.BSSID != null)
                    d.put(KEY_ADDRESS, result.BSSID);
                if (result.SSID != null)
                    d.put(KEY_NAME, result.SSID);
                if (result.capabilities != null)
                    d.put(KEY_CAPABILITIES, result.capabilities);
                d.put(KEY_LEVEL, result.level);
                ds.put(d);
            }
            onNewValue(value);
        } catch (JSONException e) {
            // shouldn't
        }
    }

}