Develop Reference

Why isn't my AlarmManager working?

I am trying to make an alarm that triggers an event some number of seconds from now, one time, from within a DialogFragment.
Here is the relevant code, I put in onCreate():
broadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context c, Intent i) {
Toast.makeText(c, "Rise and Shine!", Toast.LENGTH_LONG).show();
}
};
getActivity().registerReceiver(broadcastReceiver, new IntentFilter(ALARM_MANAGER_TAG) );
pendingIntent = PendingIntent.getBroadcast(getActivity(), 0, new Intent(ALARM_MANAGER_TAG), 0 );
alarmManager = (AlarmManager)(getActivity().getSystemService( Context.ALARM_SERVICE ));
And then when I press the start button:
alarmManager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, timestampEnd, pendingIntent);
In this case timestampEnd = System.currentTimeMillis() + 10 * 1000;, 10 seconds.
And then I have overridden destroy:
#Override
public void onDestroy() {
alarmManager.cancel(pendingIntent);
getActivity().unregisterReceiver(broadcastReceiver);
super.onDestroy();
}
And yet, nothing happens for some reason.

You're passing AlarmManager.ELAPSED_REALTIME_WAKEUP, which means the AlarmManager is going to use SystemClock.elapsedRealtime() when checking timestamps. Since you're passing something calculated off of System.currentTimeMillis(), you are going to have to wait about 47 years before the alarm fires.
Either change your first argument to AlarmManager.RTC_WAKEUP or change your timestamp to be calculated off of SystemClock.elapsedRealtime().

alarm manager/ service/ broadcast receiver is not working after app is closed or swiped away from the recent app

I know there are so many questions about this.
I tried most of them and spent so much time on it.
but not getting any solution
Actually, I want a background process to run to infinite time even app is removed from recent app
I want to take GPS location of user repetitively after 15 minute
so first I had tried with following
TRY 1******
I have created broadcast receiver who will call my service
name of that broadcast receiver is LocationServiceRestarter
I am initiating alarm repeater who will call LocationServiceRestarter at regular interval of 5 seconds
Intent intent = new Intent("com.lmf.overduereport.gpstimer.LocationServiceRestarter");
intent.addFlags(Intent.FLAG_INCLUDE_STOPPED_PACKAGES);
PendingIntent pendingIntent = PendingIntent.getBroadcast(getApplicationContext(),
0, intent, PendingIntent.FLAG_CANCEL_CURRENT);
AlarmManager am =
(AlarmManager)getSystemService(Activity.ALARM_SERVICE);
alarm_manager.setRepeating(AlarmManager.RTC_WAKEUP,SystemClock.elapsedRealtime()+5*1000,5*1000,pendingIntent);
it works fine if I don't remove app from recent apps
I have added a log inside broadcast receiver who writes log in my folder about if broadcast receiver called or not.
in this case broadcast receiver itself is not called from alarm manager then it will obviously not call service that i want to be called to record location.
TRY 2******
I have also tried services who can run infinitely. but it also stops working after app closes
TRY 3******
This time I will not call repetitive alarm manager instead of that I did following
Intent intent = new Intent("com.lmf.overduereport.gpstimer.LocationServiceRestarter");
intent.addFlags(Intent.FLAG_INCLUDE_STOPPED_PACKAGES);
PendingIntent pendingIntent = PendingIntent.getBroadcast(getApplicationContext(),
0, intent, PendingIntent.FLAG_CANCEL_CURRENT);
AlarmManager am =
(AlarmManager)getSystemService(Activity.ALARM_SERVICE);
//--
am.set(AlarmManager.ELAPSED_REALTIME_WAKEUP,
SystemClock.elapsedRealtime() + 5000, pendingIntent);
above will call broadcast receiver and in broadcast receiver I have added alarm manager as follows
LocationServiceM.appendLog("Got Reciever******");
intent = new Intent("com.lmf.overduereport.gpstimer.LocationServiceRestarter");
intent.addFlags(Intent.FLAG_INCLUDE_STOPPED_PACKAGES);
PendingIntent pendingIntent = PendingIntent.getBroadcast(context,
12345, intent, PendingIntent.FLAG_CANCEL_CURRENT);
AlarmManager am =
(AlarmManager) context.getSystemService(Activity.ALARM_SERVICE);
am.set(AlarmManager.ELAPSED_REALTIME_WAKEUP,
SystemClock.elapsedRealtime() + 5000, pendingIntent);
above will reinitiate broadcast receiver with new schedule time so chain will continue.
but sadly that also don't work. it works fine if app is not removed from the recent app.
even I had tried same above thing with service and intent service with no luck.
Conclusion: alarm manager or Broadcast receiver is not called after app is removed from the recent app.
but I have seen many app that runs in background even app is closed from recent app.

you can use START_STICKY which tells the OS to recreate the service after it has enough memory and call onStartCommand() again with a null intent. START_NOT_STICKY tells the OS to not bother recreating the service again.
you can use a service to fired when app is closed or kill from the task:
public class SensorService extends Service {
public int counter=0;
public SensorService(Context applicationContext) {
super();
Log.i("HERE", "here I am!");
}
public SensorService() {
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
super.onStartCommand(intent, flags, startId);
startTimer();
return START_STICKY;
}
#Override
public void onDestroy() {
super.onDestroy();
Log.i("EXIT", "ondestroy!");
Intent broadcastIntent = new Intent("uk.ac.shef.oak.ActivityRecognition.RestartSensor");
sendBroadcast(broadcastIntent);
stoptimertask();
}
private Timer timer;
private TimerTask timerTask;
long oldTime=0;
public void startTimer() {
//set a new Timer
timer = new Timer();
//initialize the TimerTask's job
initializeTimerTask();
//schedule the timer, to wake up every 1 second
timer.schedule(timerTask, 1000, 1000); //
}
/**
* it sets the timer to print the counter every x seconds
*/
public void initializeTimerTask() {
timerTask = new TimerTask() {
public void run() {
Log.i("in timer", "in timer ++++ "+ (counter++));
}
};
}
/**
* not needed
*/
public void stoptimertask() {
//stop the timer, if it's not already null
if (timer != null) {
timer.cancel();
timer = null;
}
}
#Nullable
#Override
public IBinder onBind(Intent intent) {
return null;
}
you also need a BroadcastReceiver which will receive a signal when someone or something kills the service; its role is to restart the service.
public class SensorRestarterBroadcastReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Log.i(SensorRestarterBroadcastReceiver.class.getSimpleName(), "Service Stops! Oooooooooooooppppssssss!!!!");
context.startService(new Intent(context, SensorService.class));;
}
}
For full implementation see this link
http://fabcirablog.weebly.com/blog/creating-a-never-ending-background-service-in-android

how can I set repeating alarm every 5 second to show message

here is my code in application class inside oncreate method: But I can't see any message from my app. Can anyone help me to do this?
Intent alarmIntent = new Intent(this, AlarmReceiver.class);
pendingIntent = PendingIntent.getBroadcast(this, 0, alarmIntent, 0);
public void startAlarm() {
manager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
int interval = 5000;
manager.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), interval, pendingIntent);
Toast.makeText(this, "Alarm Set", Toast.LENGTH_SHORT).show();
}
And on the broadcast receiver class I have the following code
public class AlarmReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context arg0, Intent arg1) {
// For our recurring task, we'll just display a message
Toast.makeText(arg0, "I'm running", Toast.LENGTH_SHORT).show();
}
}

Edited answer:
Use setInexactRepeating() instead of setRepeating(). setRepeating only takes set intervals with the shortest being INTERVAL_FIFTEEN_MINUTES. setInexactRepeating() is the only way to set a repeating interval as short as 1000ms, or 5000ms in your case.
Change:
manager.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), interval, pendingIntent);
to
manager.setInexactRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), interval, pendingIntent);

If you are not getting the exact 5 second delay that you need, you will need to use a Handler. Any type of alarm with a 5 second delay will not work properly because as of Android 5.x basically all repeating alarms are inexact to save battery life.
I have modified your code to use a Handler:
startAlarm();
public void startAlarm() {
final Handler h = new Handler();
final int delay = 5000; //milliseconds
h.postDelayed(new Runnable(){
public void run(){
//do something
Intent alarmIntent = new Intent(getApplicationContext(), AlarmReceiver.class);
sendBroadcast(alarmIntent);
h.postDelayed(this, delay);
}
}, delay);
}
That alarm method will work with your current BroadcastReceiver and do an actual 5 second delay.

How to have control on the object that started a background process in android, after the application is closed?

I used AlarmManager to schedule recurring background task. When an alarm is triggered, a Pending Intent is broadcast by the Android system. The receiver class simply displays a toast repeatedly, every 10 sec. I have created the intent in startAlarm method, and cancel in cancelAlarm method.
My problem is: when I close the application after creating the alarm, the toast is getting displayed continuously, and when I reopen the app, I lose control on the object that created the background task, so I cannot cancel it. Help?
Here are the methods that control the alarm :
public void startAlarm(Context context)
{
ser=(AlarmManager)context.getSystemService(context.ALARM_SERVICE);
Intent serviceIntent = new Intent(context, AlarmReceiver.class);
pi=PendingIntent.getBroadcast(context, 0, serviceIntent, PendingIntent.FLAG_CANCEL_CURRENT);
Calendar cal=Calendar.getInstance();
cal.add(Calendar.SECOND, 10);
ser.setInexactRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), REPEAT_TIME, pi);
}
public void cancelAlarm(Context context)
{
if (ser != null)
{
ser.cancel(pi);
ser=null;
Toast.makeText(context, "Alarm Canceled", Toast.LENGTH_SHORT).show();
}
}
And here is the receiver class for the alarm:
public class AlarmReceiver extends BroadcastReceiver
{
#Override
public void onReceive(Context arg0, Intent arg1)
{
Toast.makeText(arg0, "I'm running", Toast.LENGTH_SHORT).show();
}
}

for control of background service you can use
Process.killProcess(int pid)
ActivityManager.killBackgroundProcesses(String packageName)
or forceclose
Intent intent = new Intent(yourCurrentActivity.this,yourNextActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
android.os.Process.killProcess(android.os.Process.myPid());
or for alarm manager u can blew code to cancel alarm.
Depending on your app, you may want to include the ability to cancel the alarm. To cancel an alarm, call cancel() on the Alarm Manager, passing in the PendingIntent you no longer want to fire. For example:
//If the alarm has been set, cancel it.
if (alarmMgr!= null) {
alarmMgr.cancel(alarmIntent);
}

How to schedule an android service to execute at a fixed rate

I am working on an application that should download a file from the network every X seconds to check for any change, I use a service to do that, but its execution is not fixed with the delay time rate, here is my code for the service:
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Toast.makeText(this, "service starting", Toast.LENGTH_SHORT).show();
checkUpdate();
return START_STICKY;
}
private Void checkUpdate() {
timer.scheduleAtFixedRate(new TimerTask() {
public void run() {
Log.i("Service", String.valueOf(++counter));
if(Helper.isNetworkAvailable(getBaseContext())) {
// download file
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
}else {
Log.e("Connection", "No connection");
}
}
}, 10000, 10000);
return null;
}
The output isn't fixed, it is supposed to run every 10 seconds, while running the service run in a random manner

How about setting up an AlarmManager within an IntentService? Much more accurate.
Intent intent = new Intent(context, YourClass.class);
PendingIntent pi = PendingIntent.getService(context, 0, intent, 0);
AlarmManager am = (AlarmManager) c.getSystemService(Context.ALARM_SERVICE);
am.setRepeating(AlarmManager.RTC, System.currentTimeMillis(), 10*1000, pi);
Make sure within YourClass.class (which is an IntentService), put your logic in the handleIntent(Intent intent), which will be called every 10 seconds by the PendingIntent sent by the AlarmManager.
P.S. Update your manifest
Hope it helps

Instead of Timer Class, use AlarmManager class. It also performs the same repeating tasks you want. AlamrManager is light weight and it runs even if your device is in sleep mode.
Also see this link Android: How to repeat a service with AlarmManager

For repetitive jobs android provides simple api, called Timer please look it. Very simple to use.

Try this :
#Override
public void onStart(Intent intent, int startId) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
Log.d("Internet Available: ", ""+flag);
Calendar cal = Calendar.getInstance();
cal.add(Calendar.SECOND, 10);
Intent intent1 = new Intent(this, UpdateWidgetServiceDemo.class);
PendingIntent pintent = PendingIntent.getService(this, 0, intent1, 0);
AlarmManager alarm = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
int i;
i=15;
alarm.set(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), pintent);
super.onStart(intent, startId);
}
REMOVE return START_STICKY;