Develop Reference

Android Studio AlarmManager.cancel() closes the App

I am making an alarm app in which the alarm can be set with a toggle button. The code works in ADV, but if I test it on a real device, the the App closes imediatly after settting the alarm once and then turning it off. Also the alarm does not turn off.
(button press alarmOn -> alarm is on,
button press alarmOff-> app closes + alarm is still on)
mStartBtn1.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
long time;
if (((ToggleButton) view).isChecked()){ //if button is on
Intent intent = new Intent(MainActivity.this, AlarmReceiverActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(MainActivity.this, 2, intent, PendingIntent.FLAG_CANCEL_CURRENT);
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, timePicker1.getCurrentHour());
calendar.set(Calendar.MINUTE, timePicker1.getCurrentMinute());
time = (calendar.getTimeInMillis() - (calendar.getTimeInMillis() % 60000));
if (System.currentTimeMillis() > time) {
if (calendar.AM_PM == 0)
time = time + (1000 * 60 * 60 * 12);
else
time = time + (1000 * 60 * 60 * 24);
}
am.set(AlarmManager.RTC_WAKEUP, time, pendingIntent); //sets the alarm
}else{ //if button is off
am.cancel(pendingIntent);
}
}
});
Thank you for helping,
Florian

Your app is basically crashing. Maybe because you are passing null to am.cancel(pendingIntent)//pendingIntent might be null here.
Try moving PendingIntent pendingIntent = PendingIntent.getActivity(MainActivity.this, 2, intent, PendingIntent.FLAG_CANCEL_CURRENT); outside the if condition. If that is not the case then check AlarmReceiverActivity for crashes.

Creating a new intent inside a for loop good or bad?

I am currently stuck with the question, if creating a new intent inside a for loop is good or bad. I have the following situation:
1.
public static void reactivateReminders(Schedule schedule) {
ArrayList<Lecture> allLectures = schedule.getAllLectures();
for(Lecture lecture : allLectures) {
...
// Set up various things for the reminder
...
Intent intent = new Intent(getApplicationContext(), ReminderReceiver.class);
String at = getResources().getString(R.string.at);
String with = getResources().getString(R.string.with);
String beginH = ScheduleHelper.formatNumber(changedBeginH);
String beginM = ScheduleHelper.formatNumber(changedBeginM);
String room = lecture.getRoom();
intent.putExtra("contentText", at + " " + beginH + ":" + beginM + " in " + room + " " + with + " " + lecture.getLecturer());
PendingIntent pendingIntent = PendingIntent.getBroadcast(getApplicationContext(), lecture.getAlarmId(), intent, 0);//PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager alarm = (AlarmManager) getSystemService(ALARM_SERVICE);
if(lecture.getBeginH() != beginH || lecture.getBeginM() != beginM)
alarm.cancel(pendingIntent);
alarm.setInexactRepeating(AlarmManager.RTC, calendar.getTimeInMillis() + offset, 1000 * 60 * 60 * 24 * 7, pendingIntent);
}
}
2.
public static void reactivateReminders(Schedule schedule) {
ArrayList<Lecture> allLectures = schedule.getAllLectures();
Intent intent = new Intent(getApplicationContext(), ReminderReceiver.class);
for(Lecture lecture : allLectures) {
...
// Set up various things for the reminder
...
String at = getResources().getString(R.string.at);
String with = getResources().getString(R.string.with);
String beginH = ScheduleHelper.formatNumber(changedBeginH);
String beginM = ScheduleHelper.formatNumber(changedBeginM);
String room = lecture.getRoom();
intent.putExtra("contentText", at + " " + beginH + ":" + beginM + " in " + room + " " + with + " " + lecture.getLecturer());
PendingIntent pendingIntent = PendingIntent.getBroadcast(getApplicationContext(), lecture.getAlarmId(), intent, 0);//PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager alarm = (AlarmManager) getSystemService(ALARM_SERVICE);
if(lecture.getBeginH() != beginH || lecture.getBeginM() != beginM)
alarm.cancel(pendingIntent);
alarm.setInexactRepeating(AlarmManager.RTC, calendar.getTimeInMillis() + offset, 1000 * 60 * 60 * 24 * 7, pendingIntent);
}
}
Which option is the better one? I'm not too familiar with Java so I don't know how Java handles either one. Maybe is doesn't make a difference at all but since I'm programming in C++ normally, creating new objects inside a loop worries me.
Thanks for any help in advance.
Edit: Conclusion:
As mentioned by Alex Shutov, it better to not set all reminders at once. The user probably only needs the next one that is coming up.
To achieve this, you should set the earliest reminder somewhere in the app and store the other reminders (or rather the data you use for it) sorted in some place outside the app (XML, SQL, ...) so that your service can, after the earliest reminder set off, read the file to load the next one.
By doing this, you don't burden the system with reminders that the user doesn't even need yet. I will try to implement this idea sometime but for now I will use my approach.
Regarding my code:
A better approach for my posted code is to create the new intent once outside the loop. Since the extra I put in it has the same key, it will overwrite every time and you don't have to create a new intent. Other variables like my "at" and "with", which are constant, can be placed outside of the loop too. The variables "beginH, beginM, room" can be removed and you can just call the functions directly in the putExtra parameter. You can also place the PendingIntent and the AlarmManager line outside the loop.
I would post the code but I think my post will be too big then.
Thanks for the fast help :)

It is a bad idea, because you overload system with unneccessary tasks, you should instead schedule nearest event, in IntentService schedule next event

Can't cancel alarms for Android Alarm Manager

I'm trying to set several alarms with my app, and cancel them upon request.
I've read a lot of topics about the same, and went through the documentation, but it seems like it doesn't work.
Documentation says that cancel will try to find an intent that matches the one I provide with 'filterEquals'('Determine if two intents are the same for the purposes of intent resolution (filtering). That is, if their action, data, type, class, and categories are the same. This does not compare any extra data included in the intents.')
I'm providing same action, data, type, class, and category, so why does it not work?
Create alarm:
AlarmManager manager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
int interval = 30000;
Intent intent = new Intent(getApplicationContext(), Broadcast.class);
intent.putExtra("alarmTime",alarmTime);
intent.putExtra("reminder1",reminder1);
intent.putExtra("reminder2",reminder2);
intent.putExtra("title",title);
intent.putExtra("message",message);
intent.putExtra("vibrate",vibrate);
intent.putExtra("sound",sound);
intent.putExtra("name",name);
//Create _id from data input. is unique
int _id = 0;
for (char i: name.toCharArray()){
_id += Character.getNumericValue(i);
}
for (char i:title.toCharArray()){
_id += Character.getNumericValue(i);
}
for (char i:message.toCharArray()){
_id += Character.getNumericValue(i);
}
_id += (int) alarmTime.getTime();
_id += (int) reminder1.getTime();
_id += (int) reminder2.getTime();
Log.e("ALARMS", "Creating alarm with id: "+_id);
intent.setData(Uri.parse("custom://" + _id));
intent.setAction(String.valueOf(_id));
PendingIntent pendingUpdateIntent = PendingIntent.getBroadcast(getApplicationContext(), _id, intent, 0);
manager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime() + interval, pendingUpdateIntent);
Cancel alarm
AlarmManager manager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(getApplicationContext(), Broadcast.class);
intent.putExtra("alarmTime",alarmTime);
intent.putExtra("reminder1",reminder1);
intent.putExtra("reminder2",reminder2);
intent.putExtra("title",title);
intent.putExtra("message",message);
intent.putExtra("vibrate",vibrate);
intent.putExtra("sound",sound);
intent.putExtra("name",name);
int _id = 0;
for (char i:name.toCharArray()){
_id += Character.getNumericValue(i);
}
for (char i:title.toCharArray()){
_id += Character.getNumericValue(i);
}
for (char i:message.toCharArray()){
_id += Character.getNumericValue(i);
}
_id += (int) alarmTime.getTime();
_id += (int) reminder1.getTime();
_id += (int) reminder2.getTime();
intent.setData(Uri.parse("custom://" + _id));
intent.setAction(String.valueOf(_id));
PendingIntent pendingUpdateIntent = PendingIntent.getBroadcast(getApplicationContext(), _id, intent, 0);
Log.e("ALARMS", "Cancelling alarm with id: "+_id);
// Cancel alarms
try {
manager.cancel(pendingUpdateIntent);
} catch (Exception e) {
Log.e("ALARMS", "AlarmManager update was not canceled. " + e.toString());
}
So I call 3 times the create alarm with different parameters, so my _id is different each time.
Then I call 3 times the cancel alarm and the ids generated match for each alarm upon create and cancel.
So the cancel runs but my alarms still get fired.
My alarms trigger a broadcast receiver that will output a notification per alarm.
I forgot to mention that I tried with different flags for the PendingIntent but none work (FLAG_CANCEL_CURRENT, FLAG_UPDATE_CURRENT)

Seems like I was feeding different dates to the alarms, and the _id's were different by a couple of numbers (start and finish were the same), this resulted on calling a cancel on _id values that were different and not working.
Changed the way I generate the _id to exclude the dates (which I generated with new Date()) and not it works
By bad, I didn't see it.

Detect if current time is between two set up times

I've a program which includes service. This program has settings which allows user to set up, disable and enable time. Between these two times (if option is enabled of course), the program should not work.
I'm actually having hard time to do this. I've already sucessfully converted "disabled" and "enabled" time in milliseconds. I have following code but it doesn't work as expected. I want to detect if current time is between two set up times, so i can disable service at that time.
public boolean isCurrentTimeBetween_enableDisable() {
long sysTime = System.currentTimeMillis();
if((sysTime > disableTime && sysTime < enableTime)) {
return true;
}
return false;
}
Anyone can give me better hint?
UPDATE:
If user selects lets say
Disable hour: 15:00
Enable hour: 22:00
Then code work as expected.
But if user selects lets say:
Disable hour: 22:00
Enable hour: 06:00
Then its obviously that Enable hour is the NEXT day. So i wrote the following code:
if(todaysDisableDate(context).getTime() > enableAt.getTime()) {
enableCal.add(Calendar.DAY_OF_MONTH, 1);
enableAt = formatEnableDate.parse(enableCal.get(Calendar.DAY_OF_MONTH) + "-" +(enableCal.get(Calendar.MONTH)+1) + "-" + enableCal.get(Calendar.YEAR) + " " + endHours_string + ":" + endMinutes_string);
}
Code below is getting the actual date.
public Date todaysDisableDate(Context context) {
Calendar disableCal = Calendar.getInstance();
getTimeValues_preferences((ContextWrapper) context, true, false); // this only gets a string for hour and minute (which is set up in preferences )
Date disableAt = null;
try {
disableAt = formatDisableDate.parse(disableCal.get(Calendar.DAY_OF_MONTH)+"-"+(disableCal.get(Calendar.MONTH)+1)+"-"+disableCal.get(Calendar.YEAR)+" "+startHours_string+":"+startMinutes_string); // današnji datum z današnjo uro
} catch (ParseException e) {
e.printStackTrace();
}
return disableAt;
}
public Date todaysEnableDate(Context context) {
Calendar enableCal = Calendar.getInstance();
getTimeValues_preferences((ContextWrapper) context, false, true);
Date enableAt = null;
try {
enableAt = formatEnableDate.parse(enableCal.get(Calendar.DAY_OF_MONTH)+"-"+(enableCal.get(Calendar.MONTH)+1)+"-"+enableCal.get(Calendar.YEAR)+" "+endHours_string+":"+endMinutes_string); // današnji datum z današnjo uro
if(todaysDisableDate(context).getTime() > enableAt.getTime()) {
enableCal.add(Calendar.DAY_OF_MONTH, 1);
enableAt = formatEnableDate.parse(enableCal.get(Calendar.DAY_OF_MONTH)+"-"+(enableCal.get(Calendar.MONTH)+1)+"-"+enableCal.get(Calendar.YEAR)+" "+endHours_string+":"+endMinutes_string);
}
} catch (ParseException e) {
}
return enableAt;
}
Code is working fine if service starts before 00:00. But if the service starts after midnight (of next day), then i'm getting false from method isCurrentTimeBetween_enableDisable(), because methods todaysDisableDate(Context context) and todaysEnableDate(Context context) are pulling out the next day (the same day as system hour is in)

Do you have to compare dates in your code? If that's a project requirement then you can ignore the following.
Otherwise, I think you can use AlarmManager to create the feature without actually comparing the date. You can create a "Enable" intent and a "Disable" intent for the AlarmManager to fire at the scheduled time. Something like this:
Register your alarms when the user confirmed the time schedule.
Intent intent = new Intent(context, yourAlarmReceiver.class); //or implicit with action
PendingIntent pIntent = PendingIntent.getBroadcast(
context, requestCode, intent, PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
am.setRepeating (typeConstant, triggerAtMillis, intervalMillis, pIntent);
You just need to figure out what triggerAtMillis is to determine the first shot of that broadcast, and intervalMillis will be a full day, which is a constant in the AlarmManager class.
Setup your custom receiver class (which I wrote as yourAlarmReceiver) which should extend BroadcastReceiver, and register the receiver in your service. In the onReceive() you should perform the corresponding actions based on intent.getAction(). Don't forget to register your receiver with an intent filter if you want more customization.
#Override
public void onReceive(Context context, Intent intent) {
switch(intent.getAction()){
case "enable": //enable if not enabled
case "disable": //disable if not disabled
default: break;
}
}
In this way it may save you some time from struggling with comparing today and tomorrow. You can determine the time of the very first shot by getting the current system time, probably in 24-hour format, and determine if your intended time has already passed. Whether it's been passed, you just need to set the initial firing time to currentTime + difference.
Hope it will shed some light.

I would recommend you to use the start date and end date itself...and not convert them to miliseconds. But this is only if you're not sure.
private String compareStringOne = "9:45";
private String compareStringTwo = "1:45";
SimpleDateFormat inputParser = new SimpleDateFormat(inputFormat, Locale.US);
private void compareDates(){
Calendar now = Calendar.getInstance();
int hour = now.get(Calendar.HOUR);
int minute = now.get(Calendar.MINUTE);
date = parseDate(hour + ":" + minute);
dateCompareOne = parseDate(compareStringOne);
dateCompareTwo = parseDate(compareStringTwo);
if ( dateCompareOne.before( date ) && dateCompareTwo.after(date)) {
//This is where you determine if the date is inbetween
}
}
private Date parseDate(String date) {
try {
return inputParser.parse(date);
} catch (java.text.ParseException e) {
return new Date(0);
}
}

How to execute one task every hour?

I have been developing an Android application and I need to execute 1 task every hour. I uses the following code for it:
private static final long ALARM_PERIOD = 1000L;
public static void initAlarmManager(Context context) {
Editor editor=PreferenceManager.getDefaultSharedPreferences(context).edit();
editor.putBoolean(context.getString(R.string.terminate_key), true).commit();
AlarmManager manager = (AlarmManager) context.getSystemService(context.ALARM_SERVICE);
Intent i = new Intent(context, AlarmEventReceiver.class);
PendingIntent receiver = PendingIntent.getBroadcast(context, 0, i, 0);
manager.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP,
SystemClock.elapsedRealtime(), ALARM_PERIOD, receiver);
}
It works for me, but my client tells me that the task works only 1 time and won't work 1 hour. Where have I made a mistake? Please, tell me. Thank you.

According to your code, ALARM_PERIOD is 1000L, as repeating interval. So I doubt the alarm will set of in every 1000 milliseconds.
if you are setting repeating interval for every hour, it should be 3600000L.
And take note that if the phone is restarted, your alarm manager will no longer work unless you start again.
Here is the my Code:
private void setAlarmManager() {
Intent intent = new Intent(this, AlarmReceiver.class);
PendingIntent sender = PendingIntent.getBroadcast(this, 2, intent, 0);
AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
long l = new Date().getTime();
if (l < new Date().getTime()) {
l += 86400000; // start at next 24 hour
}
am.setRepeating(AlarmManager.RTC_WAKEUP, l, 86400000, sender); // 86400000
}

Have you added receiver tag in application tag in manifest.xml
<receiver android:name=".AlarmReceiver" android:process=":remote"/>

Instead of Alram-Manager I recommended you to use Android-TimerTask
The TimerTask class represents a task to run at a specified time. The task may be run once or repeatedly. Its perfect suits for your requirements.

Try by modifying your code by changing your setRepeating() method like this
manager.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP,SystemClock.elapsedRealtime(), SystemClock.elapsedRealtime()+(60*60*1000), receiver);
OR
Test this it is repeating for every minute
manager.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP,Calendar.getInstance().getTimeInMillis(), Calendar.getInstance().getTimeInMillis()+(1*60*1000), receiver);