Develop Reference

Background Service gets killed on clearing from recents in MIUI

Jugnoo Driver App has not been whitelisted in the Auto Start but yet it again starts the service after some time !
How jugnoo rider app runs even it is not Auto start too
I have done notification stuff , changed the manifest to stopWithTask="false" .

I have created a service for same issue,
please check it out with this.
It will help you
public class GpsServices extends Service implements LocationListener, GpsStatus.Listener {
Data data;
private LocationManager mLocationManager;
private SharedPreferences sharedPreferences;
private Data.onGpsServiceUpdate onGpsServiceUpdate;
private Looper mServiceLooper;
private ServiceHandler mServiceHandler;
public String gps_notification = "gps_channel";
#SuppressLint("MissingPermission")
#Override
public void onCreate() {
// Start up the thread running the service. Note that we create a
// separate thread because the service normally runs in the process's
// main thread, which we don't want to block. We also make it
// background priority so CPU-intensive work will not disrupt our UI.
HandlerThread thread = new HandlerThread("ServiceStartArguments", Process.THREAD_PRIORITY_BACKGROUND);
thread.start();
// Get the HandlerThread's Looper and use it for our Handler
mServiceLooper = thread.getLooper();
mServiceHandler = new ServiceHandler(mServiceLooper);
sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
if (data == null) {
data = new Data(onGpsServiceUpdate);
} else {
data.setOnGpsServiceUpdate(onGpsServiceUpdate);
}
gpsListener();
mLocationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
if (mLocationManager.getAllProviders().indexOf(LocationManager.GPS_PROVIDER) >= 0) {
mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 500, 0, this);
} else {
Log.w("SideMenuActivity", "No GPS location provider found. GPS data display will not be available.");
}
if (!mLocationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
Toast.makeText(this, "Gps not enabled", Toast.LENGTH_SHORT).show();
}
}
public void onLocationChanged(Location location) {
Gson gson = new Gson();
String json = sharedPreferences.getString("data", "");
data = gson.fromJson(json, Data.class);
if (data == null) {
data = new Data(onGpsServiceUpdate);
} else {
data.setOnGpsServiceUpdate(onGpsServiceUpdate);
}
String speed = String.format(Locale.ENGLISH, "%.0f", location.getSpeed() * 3.6);
Toast.makeText(this, speed, Toast.LENGTH_SHORT).show();
Log.e("isRunningFalse", speed);
}
#Override
public void onTaskRemoved(Intent rootIntent) {
super.onTaskRemoved(rootIntent);
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
// For each start request, send a message to start a job and deliver the
// start ID so we know which request we're stopping when we finish the job
Message msg = mServiceHandler.obtainMessage();
msg.arg1 = startId;//needed for stop.
if (intent != null) {
msg.setData(intent.getExtras());
mServiceHandler.sendMessage(msg);
} else {
Toast.makeText(GpsServices.this, "The Intent to start is null?!", Toast.LENGTH_SHORT).show();
}
return START_STICKY;
}
#Override
public IBinder onBind(Intent intent) {
// We don't provide binding, so return null
return null;
}
/* Remove the locationlistener updates when Services is stopped */
#Override
public void onDestroy() {
mLocationManager.removeUpdates(this);
mLocationManager.removeGpsStatusListener(this);
stopForeground(true);
}
#Override
public void onGpsStatusChanged(int event) {
switch (event) {
case GpsStatus.GPS_EVENT_SATELLITE_STATUS:
#SuppressLint("MissingPermission") GpsStatus gpsStatus = mLocationManager.getGpsStatus(null);
int satsInView = 0;
int satsUsed = 0;
Iterable<GpsSatellite> sats = gpsStatus.getSatellites();
for (GpsSatellite sat : sats) {
satsInView++;
if (sat.usedInFix()) {
satsUsed++;
}
}
if (satsUsed == 0) {
data.setRunning(false);
stopService(new Intent(getBaseContext(), GpsServices.class));
// firstfix = true;
}
break;
case GpsStatus.GPS_EVENT_STOPPED:
if (!mLocationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
Toast.makeText(this, "Gps not enabled.", Toast.LENGTH_SHORT).show();
}
break;
case GpsStatus.GPS_EVENT_FIRST_FIX:
break;
}
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
// Handler that receives messages from the thread
private final class ServiceHandler extends Handler {
public ServiceHandler(Looper looper) {
super(looper);
}
#Override
public void handleMessage(Message msg) {
//promote to foreground and create persistent notification.
//in Oreo we only have a few seconds to do this or the service is killed.
Notification notification = getNotification("App is running");
startForeground(msg.arg1, notification); //not sure what the ID needs to be.
// Normally we would do some work here, like download a file.
// For our example, we just sleep for 5 seconds then display toasts.
//setup how many messages
int times = 1, i;
Bundle extras = msg.getData();
if (extras != null) {
times = 1000*60*60*24; //default is one
}
//loop that many times, sleeping for 5 seconds.
for (i = 0; i < times; i++) {
synchronized (this) {
try {
wait(5000); //5 second sleep
} catch (InterruptedException e) {
}
}
String info = i + "GPS SPEED LOG";
Log.d("intentServer", info);
//make a toast
//unable to ensure the toasts will always show, so use a handler and post it for later.
// Toast.makeText(MyForeGroundService.this, info, Toast.LENGTH_SHORT).show();
}
// Stop the service using the startId, so that we don't stop
// the service in the middle of handling another job
// stopSelf(msg.arg1); //notification will go away as well.
}
}
// build a persistent notification and return it.
public Notification getNotification(String message) {
return new NotificationCompat.Builder(getApplicationContext(), gps_notification)
.setSmallIcon(android.R.drawable.ic_menu_mylocation)
.setOngoing(true) //persistent notification!
.setChannelId(gps_notification)
.setContentTitle("Gps Service") //Title message top row.
.setContentText(message) //message when looking at the notification, second row
.build(); //finally build and return a Notification.
}
}

how to stop a service running multiple instance?

I am developing a android app, which will update device location after 4 seconds interval and depending on the response received from the server it will open specific activity.
Problem 1) In some case it will open up a activity like incoming phone call with sound. I am facing problem when I am removing the app from recent app. I noticed the poll function is running twice at the same time, and multiple media is playing at the same time.
Problem 2) I am using Service intead of IntentService(I am a beginner and not sure which will be better). The background service should run even the phone goes to sleep mode, just like WhatsApp or other messenger run.
As the file is big enough, I am attaching only important part
public class TaxiNorrService extends Service implements LocationListener {
...
...
final Handler poll_handler = new Handler();
private NotificationManager mNM;
private final Actions actions = new Actions();
public Ringtone r;
private String newtext;
private Runnable BreakRunnable;
private Runnable poll_runnable;
private Handler BreakHandler;
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
poll_runnable = new Runnable() {
#Override
public void run() {
if(!App.isAutoBreak()){
if(BreakHandler !=null){
BreakHandler.removeCallbacks(BreakRunnable);
}
if(r != null) {
if (r.isPlaying()) {
r.stop();
}
}
}
if (actions.checkPermission(getApplicationContext())) {
checkGPS();
if(isNetworkAvailable()){
if(App.isPollOn()){
poll(latitude, longitude);
}
}else{
if(BreakHandler !=null){
BreakHandler.removeCallbacks(BreakRunnable);
}
boolean foregroud = false;
try {
foregroud = new ForegroundCheckTask().execute(getApplication()).get();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
boolean background = isMyServiceRunning(TaxiNorrService.class);
if(foregroud == true && background == true && App.isAppForground()){
if(!App.isLoadingVisible()){
Intent intent = new Intent(TaxiNorrService.this, Loading_activity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
}
}
}
poll_handler.postDelayed(this, 4000);
}
};
return Service.START_STICKY;
}
private void poll(double lat, double lon){
//Connected to API endpoint
}
...
...
#Override
public void onDestroy() {
if(r != null) {
if (r.isPlaying()) {
r.stop();
}
}
poll_handler.removeCallbacks(poll_runnable);
super.onDestroy();
}
}

I found the answer for my questions. The code written in the onStartCommand should be within onCreate function. This is because onCreate will execute when service starts first time, and onStartCommand will execute every time when you start the app. Please follow this topic,
Android - running a method periodically using postDelayed() call

FusedLocationApi Background Location service stops receiving updates randomly

i'm trying to use FusedLocationApi with pending intent to get period location updates so i can send the data to some server for processing. Everything works. However, there are some instances where the broadcast just stops receiving. I would need to restart the service again in order for it to continue.
I already have the service onStartCommand to return START_STICKY so even if the app is killed it should start the service again. Furthermore, I also added a Boot Completed Intent Receiver so if the phone died and user restarted phone it would restart my service.
So it seems everything is fine and working but just at some point, everything just stops. I did notice a few times that when it does stop working, the last location i received was NULL (i log every location update and error messages throughout my project).
Any ideas why location services just stops working?
P.S. there is no connection failure because i put a message and hook into that function and it's not being called. And it's not internet failure either as i log that as well. Once internet is restored it would continue as normal/expected.
Thanks.
This is the main activity:
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ActionBar actionBar = getSupportActionBar();
if (actionBar != null) {
actionBar.setDisplayShowHomeEnabled(false);
actionBar.setDisplayShowTitleEnabled(false);
if (findViewById(android.R.id.home) != null) {
findViewById(android.R.id.home).setVisibility(View.GONE);
}
LayoutInflater inflator = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = inflator.inflate(R.layout.header_logo, null);
ActionBar.LayoutParams params = new ActionBar.LayoutParams(ActionBar.LayoutParams.WRAP_CONTENT, ActionBar.LayoutParams.WRAP_CONTENT, Gravity.CENTER);
actionBar.setDisplayShowCustomEnabled(true);
actionBar.setCustomView(view, params);
}
setContentView(R.layout.activity_main);
TextView textView = (TextView) findViewById(R.id.status_text);
// init preferences and status handler
MyStatusHandler.init(getApplicationContext(), textView);
// init web service call class
...;
// check for location services
if (!isLocationEnabled(getApplicationContext())){
String msg = "Location services not turned on";
MyStatusHandler.setStatusText(msg);
}
}
public static boolean isLocationEnabled(Context context) {
int locationMode = 0;
String locationProviders;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT){
try {
locationMode = Settings.Secure.getInt(context.getContentResolver(), Settings.Secure.LOCATION_MODE);
} catch (Settings.SettingNotFoundException e) {
e.printStackTrace();
}
return locationMode != Settings.Secure.LOCATION_MODE_OFF;
}else{
locationProviders = Settings.Secure.getString(context.getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED);
return !TextUtils.isEmpty(locationProviders);
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
// create new intent activity for the settings page
Intent i = new Intent(this, MySettingsActivity.class);
startActivity(i);
return true;
}
else if (id == R.id.action_about){
// 1. Instantiate an AlertDialog.Builder with its constructor
AlertDialog.Builder builder = new AlertDialog.Builder(this);
// 2. Chain together various setter methods to set the dialog characteristics
if (Constants.DEBUG_BUILD == true) {
builder.setMessage("v." + MyStatusHandler.getReleaseVersionNum() + " dev Build: " + MyStatusHandler.getDevVersionNum())
.setTitle("About")
.setCancelable(false)
.setPositiveButton("OK", null);
}
else{
builder.setMessage("v." + MyStatusHandler.getReleaseVersionNum())
.setTitle("About")
.setCancelable(false)
.setPositiveButton("OK", null);
}
// 3. Get the AlertDialog from create()
AlertDialog dialog = builder.create();
// show it
dialog.show();
return true;
}
return super.onOptionsItemSelected(item);
}
// check email entered
public boolean isSettingsEntered(){
boolean result = true;
if (MyStatusHandler.getEmailText().equals("") || MyStatusHandler.getPasswordText().equals("")){
// 1. Instantiate an AlertDialog.Builder with its constructor
AlertDialog.Builder builder = new AlertDialog.Builder(this);
// 2. Chain together various setter methods to set the dialog characteristics
builder.setMessage("Please ensure both email and password are entered in settings")
.setTitle("Email and/or Password not set")
.setCancelable(false)
.setPositiveButton("OK",null);
// 3. Get the AlertDialog from create()
AlertDialog dialog = builder.create();
// show it
dialog.show();
result = false;
}
return result;
}
/** Called when the user clicks the Opt in button */
public void startService(View view) {
// Do something in response to button
if (isSettingsEntered() && isLocationEnabled(getApplicationContext())) {
// send opt in to web service
...;
// start service
startService(new Intent(this, BackgroundLocationService.class));
// update status text
String msg = "Connecting ...";
MyStatusHandler.setStatusText(msg);
}
}
/** Called when the user clicks the Opt out button */
public void stopService(View view) {
// Do something in response to button
if (isSettingsEntered() && isLocationEnabled(getApplicationContext())) {
// send OptOut to web service
...;
// update status text
String msg = "Connecting ...";
MyStatusHandler.setStatusText(msg);
}
}
public static void ...(boolean isOptIn, Location location, boolean sendOptIn){
if (sendOptIn)
{
// send opt in via async task
}
else{
// send location via async task
}
}
// Handle results returned to the FragmentActivity by Google Play services
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// Decide what to do based on the original request code
switch (requestCode) {
case Constants.CONNECTION_FAILURE_RESOLUTION_REQUEST :
// log the error
MyStatusHandler.logDataToFile("Connection Failure Resolution Request - Result Code: "+String.valueOf(resultCode));
// If the result code is Activity.RESULT_OK, try to connect again
switch (resultCode) {
case Activity.RESULT_OK :
// Try the request again
MyStatusHandler.logDataToFile("Attempting to re-start service");
// start service
startService(new Intent(this, BackgroundLocationService.class));
break;
}
}
}
}
Here is the background service:
public class BackgroundLocationService extends Service implements
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
public static final String TAG = BackgroundLocationService.class.getSimpleName();
private GoogleApiClient mGoogleApiClient;
private boolean mInProgress;
private LocationRequest mLocationRequest;
public void onCreate(){
super.onCreate();
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
#Override
public int onStartCommand (Intent intent, int flags, int startId) {
super.onStartCommand(intent, flags, startId);
if(mGoogleApiClient.isConnected() || mInProgress)
return START_STICKY;
if(!mGoogleApiClient.isConnected() || !mGoogleApiClient.isConnecting() && !mInProgress) {
mInProgress = true;
mGoogleApiClient.connect();
}
return START_STICKY;
}
#Override
public IBinder onBind(Intent intent) {
// TODO: Return the communication channel to the service.
throw new UnsupportedOperationException("Not yet implemented");
}
#Override
public void onConnected(Bundle bundle) {
mLocationRequest = LocationRequest.create()
.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
.setFastestInterval(Constants.FASTEST_INTERVAL)
.setInterval(Constants.UPDATE_INTERVAL);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0,
new Intent(this, MyLocationHandler.class),
PendingIntent.FLAG_CANCEL_CURRENT);
if (mGoogleApiClient.isConnected()) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, pendingIntent);
}
else{
MyStatusHandler.setStatusText("Google Client Failed");
}
}
#Override
public void onConnectionSuspended(int i) {
}
#Override
public void onLocationChanged(Location location) {
}
#Override
public void onConnectionFailed(ConnectionResult connectionResult) {
mInProgress = false;
if (connectionResult.hasResolution()) {
try {
// Start an Activity that tries to resolve the error
connectionResult.startResolutionForResult(null, Constants.CONNECTION_FAILURE_RESOLUTION_REQUEST);
// * Thrown if Google Play services canceled the original
// * PendingIntent
} catch (IntentSender.SendIntentException e) {
// Log the error
e.printStackTrace();
}
} else {
//* If no resolution is available, display a dialog to the
// * user with the error.
Log.i(TAG, "Location services connection failed with code " + connectionResult.getErrorCode());
MyStatusHandler.setStatusText("Location services connection failed with code " + connectionResult.getErrorCode());
}
}
#Override
public void onDestroy(){
mInProgress = false;
if (mGoogleApiClient.isConnected()) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
mGoogleApiClient.disconnect();
}
super.onDestroy();
}
}
Here is the broadcast receiver:
public class MyLocationHandler extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Location location = intent.getParcelableExtra(FusedLocationProviderApi.KEY_LOCATION_CHANGED);
if (location != null && MyStatusHandler.getOptInStatus()) {
// debug messages
String msg = Double.toString(location.getLatitude()) + "," +
Double.toString(location.getLongitude());
Log.d("debug", msg);
// log location to file
MyStatusHandler.logDataToFile("Location: "+msg);
// send Location to web service
MainActivity....(MyStatusHandler.getOptInStatus(), location, false);
}
if (location == null){
MyStatusHandler.logDataToFile("Location == NULL!");
}
}
}
I have set the interval to 5minutes and Fast interval to 2minutes.
NOTE: i removed some function calls and code for the web service operations
Everything works and i get updates as expected but at some point in time, the broadcast receiver doesn't get anything. When i check the logs, OptInStatus doesn't change and the last location broadcast i received was NULL.
The other parts of my code to call the web service and handle the status messages doesn't touch the service or location requests.

How do you determine the Android wifi startScan method is complete in order to calculate the time taken for the wifi scan?

code for calculating start and end time of scan. Calling scanTime as soon as the scan starts and retTime as soon as the results are received, however, getting two retTimes and the difference between scanTime and retTime is not consistent
public void startService() {
br = new BroadcastReceiver() {
#Override
public void onReceive(Context c, Intent intent) {
if (location != null) {
retTime = System.currentTimeMillis() / 1000L;
Log.i("end", Long.toString(retTime));
sendResults(wifi.getScanResults(), androidID, Long.toString(retTime), location);
Long result = retTime - scanTime;
} else {
Log.i("Location", "is Missing");
}
}
};
context.registerReceiver(br, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
t = new Thread(new Runnable() {
public void run() {
try {
setSleepTime(dataTimeDifference);
while (!Thread.interrupted()) {
wifi.startScan();
scanTime = System.currentTimeMillis() / 1000L;
Log.i("start", Long.toString(scanTime));
Thread.sleep(sleepingTime);
}
} catch (InterruptedException e) {
}
}
});
t.start();
}

In short, you know the scan is complete when the BroadcastReceiver is triggered.
This may not directly answer your question, but it seems that this might be a better way of implementing the functionality that you want.
Instead of using Thread.sleep() and a while loop in your Runnable, just rely on the BroadcastReceiver in order to determine when to start a new scan.
Also keep in mind that both the user and the OS can initiate scans, and your BroadcastReceiver will be triggered when those scans complete as well.
private final Runnable mStartScan = new Runnable() {
#Override
public void run() {
wifi.startScan();
}
};
public void startService() {
br = new BroadcastReceiver() {
#Override
public void onReceive(Context c, Intent intent) {
String action = intent.getAction();
if (action.equals(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)){
if (location != null) {
sendResults(wifi.getScanResults(), androidID, Long.toString(retTime), location);
} else {
Log.i("Location", "is Missing");
}
t = new Thread(mStartScan);
t.start();
}
}
};
context.registerReceiver(br, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
t = new Thread(mStartScan);
t.start();
}

BroadcastReceiver not being called after activity resume

First of all I'm a novice to android, so this could probably be a silly issue, nevertheless I've already spent a couple of days trying to get to a solution.
I'm trying to build a wifi module for localization purpouses, so I wrote a BroadcastReceiver in order to handle the wifi scanning and the localization. The application works and does its (quite simple at this stage) job, with anu kind of issues both when I change the orientation of the screen and when I hit the back button on my Desire HD and then open the application again. But when I hit the HOME key, going to the main screen, and then enter again my app the Broadcast Receiver seems not to work anymore, and if I close the application I get an error message.
Here's the code, partially adapted from here.
public class WiFiDemo extends Activity implements OnClickListener {
private static final String TAG = "WiFiDemo";
WifiManager wifi;
BroadcastReceiver receiver;
WifiManager.WifiLock lock;
boolean wifiPrevState;
boolean scanON = false;
String header;
TextView textStatus;
Button buttonScan;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Setup UI
textStatus = (TextView) findViewById(R.id.textStatus);
buttonScan = (Button) findViewById(R.id.buttonScan);
buttonScan.setOnClickListener(this);
// Setup WiFi
if (wifi == null){
wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
}
//checking WiFi status, enabling it if needed and locking it.
wifiPrevState = wifi.isWifiEnabled();
wifi.setWifiEnabled(true);
if (lock == null){
lock = wifi.createWifiLock("lock");
}
lock.acquire();
// Get WiFi status
WifiInfo info = wifi.getConnectionInfo();
header="\n\nWiFi Status: \n" + info.toString() + "\n\nAvailable nets:";
textStatus.append(header);
// Register Broadcast Receiver
if (receiver == null)
receiver = new WiFiScanReceiver(this);
registerReceiver(receiver, new IntentFilter(
WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
Log.d(TAG, "onCreate()");
}
/*
#Override
protected void onPause(){
super.onPause();
wifi.setWifiEnabled(wifiPrevState);
lock.release();
unregisterReceiver(receiver);
Log.d(TAG, "onPause()");
}
#Override
protected void onResume(){
super.onResume();
wifi.setWifiEnabled(true);
lock.acquire();
registerReceiver(receiver, new IntentFilter(
WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
Log.d(TAG, "onResume()");
}
*/
#Override
public void onStop() {
super.onStop();
wifi.setWifiEnabled(wifiPrevState);
lock.release();
unregisterReceiver(receiver);
}
public void onClick(View view) {
Toast.makeText(this, "On Click Clicked. Toast to that!!!",
Toast.LENGTH_LONG).show();
if (view.getId() == R.id.buttonScan) {
Log.d(TAG, "onClick() wifi.startScan()");
scanON = !scanON;
wifi.startScan();
}
}
}
And this is the BroadcastReceiver
public class WiFiScanReceiver extends BroadcastReceiver {
private static final String TAG = "WiFiScanReceiver";
WiFiDemo wifiDemo;
ScanResult storedBest;
public WiFiScanReceiver(WiFiDemo wifiDemo) {
super();
this.wifiDemo = wifiDemo;
storedBest = null;
}
#Override
public void onReceive(Context c, Intent intent) {
List<ScanResult> results = wifiDemo.wifi.getScanResults();
ScanResult bestSignal = null;
wifiDemo.textStatus.setText(wifiDemo.header);
for (ScanResult result : results) {
if (bestSignal == null
|| WifiManager.compareSignalLevel(bestSignal.level, result.level) < 0)
bestSignal = result;
wifiDemo.textStatus.append("\n\n" + result.toString());
}
if ( storedBest == null || ((bestSignal.SSID.compareTo(storedBest.SSID)!=0) && bestSignal.level>-50)){
storedBest = bestSignal;
String locationMessage = String.format("You are near %s's Access Point",
bestSignal.SSID);
Toast.makeText(wifiDemo, locationMessage, Toast.LENGTH_LONG).show();
}
String message = String.format("%s networks found. %s is the strongest. Its level is %s",
results.size(), bestSignal.SSID, bestSignal.level);
if (wifiDemo.scanON) wifiDemo.wifi.startScan();
Log.d(TAG, "onReceive() message: " + message);
}
}

When posting, its best to post the error message that you are getting so we know the problem you are having.
That being said, the reason it probably isn't working is because you unregister your receiver in onStop and you only register your receiver in onCreate. You should typically do these type of calls in life cycle stages that match.
onCreate/onDestroy
onStart/onStop
onResume/onPause.
To fix your problem, try registering your receiver in onStart instead of onCreate.

Your onResume() method is commented out...
Are you sure that's the correct IntentFilter?