Develop Reference

Schedule an alarm on device reboot automatically in android

I am trying to build an application which checks for notification files on a server, every hour. I used the alarm manager class to implement this. But I am unable to implement the automatic start on reboot part. I want that the alarm should run periodically after reboot. Can some one please tell me how to go about doing it.
This is my MyAlarmReceiver Class.
package com.example.quickstart;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
public class MyAlarmReceiver extends BroadcastReceiver {
public static final int REQUEST_CODE = 12345;
public static final String ACTION = "com.example.quickstart.alarm";
// Triggered by the Alarm periodically (starts the service to run task)
#Override
public void onReceive(Context context, Intent intent) {
Intent i = new Intent(context, NotificationService.class);
// i.putExtra("username", username);
context.startService(i);
}
}
This is my NotificationBootReceiver Class.
package com.example.quickstart;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.SystemClock;
public class NotificationBootReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
// Construct an intent that will execute the AlarmReceiver
Intent i = new Intent(context, MyAlarmReceiver.class);
// Create a PendingIntent to be triggered when the alarm goes off
final PendingIntent pIntent = PendingIntent.getBroadcast(context, MyAlarmReceiver.REQUEST_CODE,
i, PendingIntent.FLAG_UPDATE_CURRENT);
// Setup periodic alarm every every half hour from this point onwards
long firstMillis = System.currentTimeMillis(); // alarm is set right away
AlarmManager alarm = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
// First parameter is the type: ELAPSED_REALTIME, ELAPSED_REALTIME_WAKEUP, RTC_WAKEUP
// Interval can be INTERVAL_FIFTEEN_MINUTES, INTERVAL_HALF_HOUR, INTERVAL_HOUR, INTERVAL_DAY
alarm.setRepeating(AlarmManager.ELAPSED_REALTIME, SystemClock.elapsedRealtime(),
2*60*60,pIntent);
// alarm.setInexactRepeating(AlarmManager.RTC_WAKEUP, firstMillis,
// AlarmManager.INTERVAL_FIFTEEN_MINUTES, pIntent);
}
}
AndroidManifest file looks like this(it's not the complete manifest file but the relevant parts)
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<receiver android:name=".NotificationBootReceiver"
android:enabled="true">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED"></action>
</intent-filter>
</receiver>
The notifications are working fine, but what I want is the start notifications automatically on reboot feature. When i reboot the notification feature does not work,i.e, the alarm does not go off. And also the android documentation says (this only works if the app has already been launched by the user at least once) , is there a way to set the alarm automatically on reboot without launching the app. Any help appreciated. Thanks in advance
Documentation link android devs link
(Go to: Start an alarm when the device restarts)

No it isn't possible to set the alarms without starting the app even once. Once the app has been started the alarms can be triggered.

I want to start my activity on a predifined time. For example 3 o'clock

Whats wrong in Code?
I have changed the time to just test.
Please provide the result in detail.
AlarmManager am = (AlarmManager) getBaseContext().getSystemService(Context.ALARM_SEDate futureDate = new Date(new Date().getTime() + 86400000);
futureDate.setHours(7);
futureDate.setMinutes(45);
futureDate.setSeconds(0);
Intent intent = new Intent(getBaseContext(), MyBroadcastReceiver.class);
PendingIntent sender = PendingIntent.getBroadcast(getBaseContext(), 0,intent,
PendingIntent.FLAG_UPDATE_CURRENT);
This is My Broadcast Reciever
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class MyBroadcastReceiver extends BroadcastReceiver {
//MediaPlayer mp;
#Override
public void onReceive(Context context, Intent intent) {
//mp=MediaPlayer.create(context, R.raw.alrm );
//mp.start();
//Toast.makeText(context, "Alarm....", Toast.LENGTH_LONG).show();
Intent scheduledIntent = new Intent(context, HorrorRes.class);
scheduledIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(scheduledIntent);
}
}

I have a lot of wisdom specifically for what you aim to achieve. I have recently published an Alarm Clock app which may only be disabled via NFC (tap-and-pay) technology.
Here are a few things you will need to do going forward:
Use getSystemService(Context.ALARM_SERVICE);
Calendar is VERY particular. Use Calendar .add() or .set() and the calendar class will change many of its internal variables appropriately.Use Calendar.getTime() will recompute all of Calendar's inner fields and then return your Date object.
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.add(Calendar.SECOND, 4);
Date date = calendar.getTime();
Log.d("WakefulReceiver", date.toString());
mAlarmManager.setExact(AlarmManager.RTC_WAKEUP, date.getTime(), mIntent);
Your Intent is looks fine.
Transition your BroadcastReceiver to being a WakefulBroadcastReceiver, this class handles your wakelock and does the heavy lifting for you. We really just want a BroadcastReceiver in Android to receive(). In the receive you can start an IntentService.
IntentService will be the class to handle the multiple things which should happen by your design. Your IntentService should: (A) start a separate service to run an Async Foreground Media Player. (B) start your activity.
I can get into much more detail, here is my Github project code.
WakefulBroadcastReceiver = /app/WakefulReceiver.java
IntentService = /app/RingingService.java
MediaPlayer (as a Foreground Async Service) = /app/AlarmService.java
Message me for more insight!

Replace Service with AlarmManager in Android

I have an android service to fetch data from the web that runs every fifteen minutes
public class SparkService extends Service {
Handler handler;
public SparkService() {
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.e("Starting Sevice", "Starting Service Successfully.");
if (handler == null) {
handler = new Handler(new Handler.Callback() {
#Override
public boolean handleMessage(Message msg) {
fetchDataFromServer();
handler.removeMessages(120);
handler.sendEmptyMessageDelayed(120, 15 * 60 * 1000);
return true;
}
});
}
handler.sendEmptyMessageDelayed(120, 15 * 60 * 1000);
return Service.START_STICKY;
}
}
I have found the service to be unreliable at times and seems like it's not being called if the app is inactive for a certain period of time. I want to replace the service with an AlarmManager service instead. My app is currently in production. Can I just delete the SparkService class and add another Alarm service class without affecting existing users who update the app? Or would I have to stop this SparkService in my app update so the app can function properly?

Your app is your entry point. So if it's killed that means all services related to its process will also be killed, like if you kill the svchost.exe process in Windows all sub processes like Windows update service will be stopped too and will not be running again until you launch the update manager.
The same goes for your app: the only way that a Service won't be stopped by killing your app (and I'm not sure about that but it can be) is if the Service is created with its own process using a special tag in the Manifest.
I think in your case you didn't set that tag so the Service will be only scheduled once your app is launched after the update and in that case the Service will behave according to the new code.

To answer your first question even if you delete the service from your update users with the old version will not be affected until they update there version with the new one
Now for using Alarm manger to trigger update from your backend as you said it's a good practice as the alarm manager have different set that you can use depending or your need below a short example how to use it
// Get alarm manager instance
AlarmManager alarmManager = (AlarmManager)getApplicationContext().getSystemService(Context.ALARM_SERVICE);
Calendar calendar;
Intent intent;
PendingIntent pendingIntent;
// Schedule
intent = new Intent(getApplicationContext(), YourCustomBroadcastReceiver.class);
pendingIntent = PendingIntent.getBroadcast(getApplicationContext(), 0, intent, 0);
calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.add(Calendar.SECOND, 1); // first time
alarmManager.setRepeating(
AlarmManager.RTC_WAKEUP,
calendar.getTimeInMillis(),
60*5*1000,//Each five minutes
pendingIntent
);
And in your broadcast receiver
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class YourBroadcastReceiver extends BroadcastReceiver{
publicYourBroadcastReceiver() {}
#Override
public void onReceive(Context context, Intent intent) {
Intent serviceIntent = new Intent(context.getApplicationContext(),YourService.class);
context.startService(serviceIntent);
}
}
And here for more details about alarm manager
http://developer.android.com/training/scheduling/alarms.html

Making an alarm program - not working

I am attempting to make alarm program. So far I have written an activity in which the user can select the time he wishes the alarm to go off. This is working fine. Now I need to use the alarm manger to tell the OS to call some of my code at a certain point in the future. Just to test this in a crude way I added the following code that gets executed when I press a test button in my main activity:
Intent intent = new Intent(getApplicationContext(), to_call_when_alarm_goes_off.class);
PendingIntent pIntent = PendingIntent.getBroadcast(getApplicationContext(),0, intent, 0);
AlarmManager alarms = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
alarms.cancel(pIntent);
alarms.setRepeating(
AlarmManager.RTC_WAKEUP,
System.currentTimeMillis()+1000,
AlarmManager.INTERVAL_DAY,
pIntent);
This should mean that some code called to_call_when_alarm_goes_off will get executed one second after I press the button.... Now this is where I'm a little confused. I'm not sure quite how/where to set up "to_call_when_alarm_goes_off". What I did was simply add a new class to my project as follows:
package com.mycompany.alarmprogram;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
public class to_call_when_alarm_goes_off extends BroadcastReceiver
{
#Override
public void onReceive(Context arg0, Intent arg1)
{
// TODO Auto-generated method stub
Log.i("ALARM","TIME TO WAKE UP!!!");
}
}
All the code compiles, and when I press the button all the code in the first code snippet gets executed without crashing - but one second later the broadcast receiver code is not executed. Clearly I am misunderstanding something.

I assume you are missing registering your receiver in Manifest file, With appropriate action string. as given below.
<receiver android:name=".to_call_when_alarm_goes_off" >
<intent-filter>
<action android:name="com.android.whatever.WHAT_EVER_NAM_YOU_WANNA_GIVE" />
</intent-filter>// can change name/action string as par ur requirement.
</receiver>
you need to set same action string in your intent, Remember Action string must be same in Manifest and here intent.setAction("com.android.whatever.WHAT_EVER_NAM_YOU_WANNA_GIVE"); in java also. then only it will tringger receiver.
Your code can be changed like given below.
Intent intent = new Intent(getApplicationContext(), to_call_when_alarm_goes_off.class);
intent.setAction("com.android.whatever.WHAT_EVER_NAM_YOU_WANNA_GIVE");// added line
PendingIntent pIntent = PendingIntent.getBroadcast(getApplicationContext(),0, intent, 0);
AlarmManager alarms = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
alarms.cancel(pIntent);
alarms.setRepeating(
AlarmManager.RTC_WAKEUP,
System.currentTimeMillis()+1000,
AlarmManager.INTERVAL_DAY,
pIntent);

You need to register to_call_when_alarm_goes_off class in AndroidManifest.xml as receiver:
<receiver android:name=".to_call_when_alarm_goes_off"></receiver>
See details in API docs.

Android broadcast reciever returns null pointer exception with extended application

Ive created a simple broadcast receiver whose only purpose is when the phone boots up to start an alarmmanager method that I tucked away in an extended application file that handles application wide tasks like this, this works fine when I call it from an activity but, when I try to call it from a broadcast receiver it crashes and does not work, what Im thinking is perhaps I need to append the context to it in some way?
here is my code :
package com.testapp21.second.activities;
import com.testapp21.second.OTweetApplication;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class PhoneOnReceiver extends BroadcastReceiver {
private OTweetApplication app;
#Override
public void onReceive(Context context, Intent intent) {
app.startChecks();
}
}
edit: startChecks then delegates off to a method in a helper file called startCheckshelper() here is what that block of code looks like this:
public void startCheckshelper(){
mAlarmSender = PendingIntent.getService(context,
0, new Intent(context, CheckerService.class), 0);
// We want the alarm to go off 30 seconds from now.
long firstTime = SystemClock.elapsedRealtime();
// Schedule the alarm!
AlarmManager am = (AlarmManager)context.getSystemService(Service.ALARM_SERVICE);
am.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP,
firstTime, 60*1000, mAlarmSender);
}

You should always post your stack trace along with your question when asking about a crash in Android, but it looks like app is never initialized, yet you use it in onReceive.

You never initialized / assigned something to app, so it's null:
private OTweetApplication app;
And when you call it (app.startChecks();) you get the exception.