How to check if AlarmManager already has an alarm set

Question

When my app starts  I want it to check if a particular alarm  registered via AlarmManager  is already set and running  Results from google seem to indicate that there is no way to do this  Is this still correct  I need to do this check in order to advise the user before any action is taken to create a new alarm

User · Answer

Based on my experience  in a more recent version of Android  I believe it only allows Broadcast messages for Alarm wake up  not starting services directly  See this link   https   developer android com training scheduling alarms  it says  Alarms have these characteristics   They let you fire Intents at set times and or intervals  You can use them in conjunction with broadcast receivers to start services and perform other operations   The operative word in the second sentence is  quot conjunction  quot  What it explicitly states is that alarms are design for Broadcast  which implies not for starting services directly    I tried for several hours to use a PendingIntent with getService    but could not get it to work  even though I confirmed the pending intent was working correctly simply using  pendingIntent send 0    For  quot targetSdkVersion 29 quot  this did not work     would not fire onStartCommand     Intent launchIntent   new Intent context  MyService class   launchIntent putExtra Type KEY  SERVER QUERY       PendingIntent pendingIntent                   PendingIntent getService context  0  launchIntent  0    I could validate the alarm was running using  adb shell dumpsys alarm   grep com myapp  However  this did work  public static class AlarmReceiverWakeup extends BroadcastReceiver         Override     public void onReceive Context context  Intent intent            Log i TAG   quot onReceive Alarm wakeup quot            startService context             public static void scheduleAlarmWakeup Context context         Intent broadcastIntent   new Intent context  AlarmReceiverWakeup class       broadcastIntent putExtra Type KEY  SERVER QUERY           PendingIntent pendingIntent                       PendingIntent getBroadcast context  0  broadcastIntent  0       AlarmManager alarmManager                    AlarmManager  context getSystemService Context ALARM SERVICE           NOTE  using System currentTimeMillis   fails w ELAPSED REALTIME WAKEUP             use SystemClock elapsedRealtime   instead     alarmManager setRepeating                  AlarmManager ELAPSED REALTIME WAKEUP                  SystemClock elapsedRealtime   5000                  AlarmManager INTERVAL FIFTEEN MINUTES 4                  getAlarmPendingIntent context            BTW  this is the AndroidManifest xml entry for the Broadcast Receiver   lt receiver android name  quot  ServerQueryService AlarmReceiverWakeup quot      android enabled  quot true quot  gt       lt intent-filter gt           lt category android name  quot android intent category DEFAULT quot   gt       lt  intent-filter gt   lt  receiver gt

User · Answer

Im under the impression that theres no way to do this  it would be nice though   You can achieve a similar result by having a Alarm last set time recorded somewhere  and having a On boot starter BroadcastReciever BOOT COMPLETED kinda thing

User · Answer

While almost everyone over here has given the correct answer  no body explained on what basis are the Alarms work  You can actually learn more about AlarmManager and its working here   But here is the quick answer  You see AlarmManager basically schedules a PendingIntent at some time in future  So in order to cancel the scheduled Alarm you need to cancel the PendingIntent    Always keep note of two things while creating the PendingIntent  PendingIntent getBroadcast context REQUEST CODE intent  PendingIntent FLAG UPDATE CURRENT      Request Code - Acts as the unique identifier Flag - Defines the behavior of PendingIntent   Now to check if the Alarm is already scheduled or to cancel the Alarm you just need to get access to the same PendingIntent  This can be done if you use same request code and use FLAG NO CREATE like shown below  PendingIntent pendingIntent PendingIntent getBroadcast this REQUEST CODE intent PendingIntent FLAG NO CREATE    if  pendingIntent  null     alarmManager cancel pendingIntent     With FLAG NO CREATE it will return null if the PendingIntent doesn t already exist  If it already exists it returns reference to the existing PendingIntent

User · Answer

Following up on the comment ron posted  here is the detailed solution   Let s say you have registered a repeating alarm with a pending intent like this   Intent intent   new Intent  com my package MY UNIQUE ACTION    PendingIntent pendingIntent   PendingIntent getBroadcast context  0                                         intent  PendingIntent FLAG UPDATE CURRENT   Calendar calendar   Calendar getInstance    calendar setTimeInMillis System currentTimeMillis     calendar add Calendar MINUTE  1    AlarmManager alarmManager    AlarmManager  context getSystemService Context ALARM SERVICE   alarmManager setRepeating AlarmManager RTC WAKEUP  calendar getTimeInMillis    1000   60  pendingIntent     The way you would check to see if it is active is to   boolean alarmUp    PendingIntent getBroadcast context  0           new Intent  com my package MY UNIQUE ACTION             PendingIntent FLAG NO CREATE     null    if  alarmUp        Log d  myTag    Alarm is already active        The key here is the FLAG NO CREATE which as described in the javadoc  if the described PendingIntent   does not   already exists  then simply return null  instead of creating a new one

User · Answer

Note this quote from the docs for the set method of the Alarm Manager      If there is already an alarm for this Intent scheduled  with the   equality of two intents being defined by Intent filterEquals   then it   will be removed and replaced by this one    If you know you want the alarm set  then you don t need to bother checking whether it already exists or not  Just create it every time your app boots  You will replace any past alarms with the same Intent   You need a different approach if you are trying to calculate how much time is remaining on a previously created alarm  or if you really need to know whether such alarm even exists  To answer those questions  consider saving shared pref data at the time you create the alarm  You could store the clock timestamp at the moment the alarm was set  the time that you expect the alarm to go off  and the repeat period  if you setup a repeating alarm

User · Answer

Working example with receiver  the top answer was just with action      starting AlarmManager alarmManager    AlarmManager  getActivity   getSystemService Context ALARM SERVICE   Intent intent   new Intent getActivity    MyReceiver class   intent setAction MyReceiver ACTION ALARM RECEIVER    my custom string action name PendingIntent pendingIntent   PendingIntent getBroadcast getActivity    1001  intent  PendingIntent FLAG CANCEL CURRENT    used unique ID as 1001 alarmManager setRepeating AlarmManager RTC WAKEUP  System currentTimeMillis    aroundInterval  pendingIntent    first start will start asap    and stopping Intent intent   new Intent getActivity    MyReceiver class    the same as up intent setAction MyReceiver ACTION ALARM RECEIVER    the same as up PendingIntent pendingIntent   PendingIntent getBroadcast getActivity    1001  intent  PendingIntent FLAG CANCEL CURRENT    the same as up alarmManager cancel pendingIntent    important pendingIntent cancel     important    checking if alarm is working with pendingIntent Intent intent   new Intent getActivity    MyReceiver class    the same as up intent setAction MyReceiver ACTION ALARM RECEIVER    the same as up boolean isWorking    PendingIntent getBroadcast getActivity    1001  intent  PendingIntent FLAG NO CREATE     null    just changed the flag Log d TAG   alarm is      isWorking         not       working         It is worth to mention      If the creating application later  process  re-retrieves the same kind of   PendingIntent  same operation  same Intent s - action  data  categories    components  flags   it will receive a PendingIntent   representing the same token if that is still valid  and can thus call   cancel   to remove it    In short  your PendingIntent should have the same features  operation and intent s structure  to take control over it

User · Answer

I have 2 alarms  I am using intent with extras instead of action to identify the events   Intent i   new Intent context  AppReciever class   i putExtra  timer    timer1      the thing is that with diff extras the intent  and the alarm  wont be unique  So to able to identify which alarm is active or not  I had to define diff requestCode-s   boolean alarmUp    PendingIntent getBroadcast context  MyApp TIMER 1  i                       PendingIntent FLAG NO CREATE     null     and here is how alarm was created   public static final int TIMER 1   1  public static final int TIMER 2   2   PendingIntent pending   PendingIntent getBroadcast context  TIMER 1  i              PendingIntent FLAG CANCEL CURRENT   setInexactRepeating AlarmManager RTC WAKEUP              cal getTimeInMillis    AlarmManager INTERVAL DAY  pending   pending   PendingIntent getBroadcast context  TIMER 2  i              PendingIntent FLAG CANCEL CURRENT   setInexactRepeating AlarmManager RTC WAKEUP              cal getTimeInMillis    AlarmManager INTERVAL DAY  pending

User · Answer

For others who may need this  here s an answer   Use adb shell dumpsys alarm  You can know the alarm has been set and when are they going to alarmed and interval  Also how many times this alarm has been invoked

User · Answer

I made a simple  stupid or not  bash script  that extracts the longs from the adb shell  converts them to timestamps and shows it in red   echo  Please set a search filter  read search  adb shell dumpsys alarm   grep  search    while read i  do echo  i   DT   echo  i   grep -Eo  when s   0-9  10      tr -d     alpha    space       if     DT    then echo -e   e 31m  date -d    DT  e 0m   fi  done     try it

User · Answer

Just found another solution  it seems to work for me  Intent myIntent   new Intent MainActivity this  MyReceiver class    boolean isWorking    PendingIntent getBroadcast MainActivity this  0  myIntent  PendingIntent FLAG NO CREATE     null   if  isWorking   Log d  alarm    is working     else  Log d  alarm    is not working      if  isWorking        pendingIntent   PendingIntent getBroadcast MainActivity this  0  myIntent     PendingIntent FLAG UPDATE CURRENT       alarmManager    AlarmManager  getSystemService ALARM SERVICE       int timeNotif   5   60   1000   time in ms  7 24 60 60 1000 for 1 week     Log d  Notif    Notification every  ms       timeNotif       alarmManager setRepeating AlarmManager RTC WAKEUP  calendar getTimeInMillis    timeNotif  pendingIntent

User · Answer

Intent intent   new Intent  com my package MY UNIQUE ACTION                PendingIntent pendingIntent   PendingIntent getBroadcast                      sqlitewraper context  0  intent                      PendingIntent FLAG NO CREATE     FLAG NO CREATE is not create pending intent so that it gives boolean value false               boolean alarmUp    PendingIntent getBroadcast sqlitewraper context  0                      new Intent  com my package MY UNIQUE ACTION                        PendingIntent FLAG NO CREATE     null                if  alarmUp                    System out print  k                                AlarmManager alarmManager    AlarmManager  sqlitewraper context                      getSystemService Context ALARM SERVICE               alarmManager setRepeating AlarmManager RTC WAKEUP                      System currentTimeMillis    1000   60  pendingIntent     After the AlarmManager check the value of Pending Intent it gives true because  AlarmManager  Update The Flag of Pending Intent                boolean alarmUp1    PendingIntent getBroadcast sqlitewraper context  0                      new Intent  com my package MY UNIQUE ACTION                        PendingIntent FLAG UPDATE CURRENT     null               if  alarmUp1                    System out print  k

[android] How to check if AlarmManager already has an alarm set?

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