Develop Reference

Continually Running Background Service

I'm targeting sdk version 27 with a minimum version of 19 and trying to get a service that runs continuously in the background. I tried different service start options but it still got killed with the app. I tried using a BroadcastReceiver to start the service when it got killed but that gave me an error saying that the app was in the background and couldn't start a service so I tried using the JobScheduler and that gave me the same error. How is this supposed to be done? For example, if I were making a pedometer app, how could I keep that running in the background?

In oreo release Android defined limits to background services.
To improve the user experience, Android 8.0 (API level 26) imposes
limitations on what apps can do while running in the background.
Still if app need to run its service always, then we can create foreground service.
Background Service Limitations: While an app is idle, there are limits
to its use of background services. This does not apply to foreground
services, which are more noticeable to the user.
So create a foreground service. In which you will put a notification for user while your service is running. See this answer (There are many others)
Now what if you don't want a notification for your service. A solution is for that.
You can create some periodic task that will start your service, service will do its work and stops itself. By this your app will not be considered battery draining.
You can create periodic task with Alarm Manager, Job Scheduler, Evernote-Jobs or Work Manager.
Instead of telling pros & cons of each one. I just tell you best. Work manager is best solution for periodic tasks. Which was introduced with Android Architecture Component.
Unlike Job-Scheduler(only >21 API) it will work for all versions.
Also it starts work after a Doze-Standby mode.
Make a Android Boot Receiver for scheduling service after device boot.
I created forever running service with Work-Manager, that is working perfectly.

Since Android 8.0 many background service limitations have been introduced.
Two solutions:
if you need to get total control of task and execution timing, you have to choose Foreground Service.
Pros: your app will be considered to be alive, then is more unlikely that the os will kill it to free resources.
Cons: your user will always see the Foreground Notification.
if you need to schedule periodically task, then Work Manager (introduced in Google I/O 18) is the best solution. This component choose the best possible scheduler (Jobscheduler, JobDispatcher, AlarmManager..). Keep in mind that work manager APIs are useful only for the tasks that require guaranteed execution and they are deferrable.
Ref: Android Dev Documentation

The only solution I would suggest is using Firebase Cloud Messages.
Or foreground services.

Using BroadcastReciever we can run backgrouund service continuously, but if it will get killed , destroy automatically re-instance the old service instance
When service stops forcefully it will call onDestroy() method, in this case use one receiver and send one broadcast when ever service destroy and restart service again. in thee following method com.android.app is custom action of reciever class which extends BroadcastReciever
public void onDestroy() {
try {
myTimer.cancel();
timerTask.cancel();
} catch (Exception e) {
e.printStackTrace();
}
Intent intent = new Intent("com.android.app");
intent.putExtra("valueone", "tostoreagain");
sendBroadcast(intent);
}
and in onReceive Method
#Override
public void onReceive(Context context, Intent intent) {
Log.i("Service Stoped", "call service again");
context.startService(new Intent(context, ServiceCheckWork.class));
}
In case device is restarted then we have onBootCompleted action for receiver to catch
When you are targeting SdkVersion "O"
In MainActivity.java define getPendingIntent()
private PendingIntent getPendingIntent() {
Intent intent = new Intent(this, YourBroadcastReceiver.class);
intent.setAction(YourBroadcastReceiver.ACTION_PROCESS_UPDATES);
return PendingIntent.getBroadcast(this, 0, intent,
PendingIntent.FLAG_UPDATE_CURRENT);
}
here we use PendingIntent with BroadcastReceiver and This BroadcastReceiver has already been defined in AndroidManifest.xml.
Now in YourBroadcastReceiver.java class which contains an onReceive() method:
Override
public void onReceive(Context context, Intent intent) {
if (intent != null) {
final String action = intent.getAction();
if (ACTION_PROCESS_UPDATES.equals(action)) {
NotificationResult result = NotificationResult.extractResult(intent);
if (result != null) {
List<Notification> notifications = result.getNotification();
NotificationResultHelper notificationResultHelper = new
NotificationResultHelper(
context, notifications);
// Save the notification data to SharedPreferences.
notificationResultHelper.saveResults();
// Show notification with the notification data.
notificationResultHelper.showNotification();
Log.i(TAG,
NotificationResultHelper.getSavedNotificationResult(context));
}
}
}
}

as you say:
I tried using a BroadcastReceiver to start the service when it got
killed but that gave me an error saying that the app was in the
background and couldn't start a service
in Oreo when you are in background and you want to start a service that service must be a foreground service use this code:
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
context.startForegroundService(intent);
} else {
context.startService(intent);
}
if you use this code in Oreo you have a few seconds in onStartCommand to start foreground otherwise your service considered as not responding and may be force close by user (in Android 8 or above)
There is no need to use BroadcastReceiver to start service after it is closed it is enough to just return START_STICKY or START_REDELIVER_INTENT from onStartCommand of your service to restart service after it is closed

A working hack for this is to simply start a foreground service which is only visible for the fraction of a second and starts your background service. In the background service you'd then periodically start the foreground service.
Before I give an example you should really ask yourself if this is the way to go for you, there might be other solutions to given problems (like using JobIntentService etc.); and keep in mind that this is a hack, it might be patched some time around and I'd generally not use it (I tested it with screen off and battery saving enabled though and it stayed alive the whole time - but this might prevent your device from dozing.. again, this is a dirty hack!)
Example:
public class TemporaryForegroundService extends Service {
public static final int NOTIFICATION_ID = 666;
private static Notification notification;
#Override
public void onCreate() {
super.onCreate();
if(notification == null)
notification = new NotificationCompat.Builder(this, NotificationChannels.importantChannel(this)).
setSmallIcon(R.mipmap.ic_launcher).setContentTitle("The unseen blade").setContentText("If you see me, congrats to you.").build();
startForeground(NOTIFICATION_ID, notification);
startService(new Intent(this, PermanentBackgroundService.class));
stopForeground(true);
stopSelf();
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
return START_NOT_STICKY;
}
#Nullable
#Override
public IBinder onBind(Intent intent) {
return null;
}
}
public class PermanentBackgroundService extends Service {
private Runnable keepAliveRunnable = new Runnable() {
#Override
public void run() {
keepServiceAlive();
if(handler != null) handler.postDelayed(this, 15*1000);
}
};
private Handler handler;
public void onCreate(){
handler = new Handler();
handler.postDelayed(keepAliveRunnable, 30* 1000);
}
public void onDestroy() {
super.onDestroy();
keepServiceAlive();
}
private void keepServiceAlive() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
startForegroundService(new Intent(PermanentBackgroundService.this, TemporaryForegroundService .class));
} else {
startService(new Intent(PermanentBackgroundService.this, TemporaryForegroundService .class));
}
}
}

Android - Periodic Background Service - Advice

I am working on an app that will relay information about its location to a remote server. I am intending to do it by doing a simple HTTP post to the web-server and all is simple and fine.
But according to the spec, the app needs to execute itself from time to time, lets say once in every 30 mins. Be independent of the interface, meaning which it needs to run even if the app is closed.
I looked around and found out that Android Services is what needs to be used. What could I use to implement such a system. Will the service (or other mechanism) restart when the phone restarts?
Thanks in advance.

Create a Service to send your information to your server. Presumably, you've got that under control.
Your Service should be started by an alarm triggered by the AlarmManager, where you can specify an interval. Unless you have to report your data exactly every 30 minutes, you probably want the inexact alarm so you can save some battery life.
Finally, you can register your app to get the bootup broadcast by setting up a BroadcastReceiver like so:
public class BootReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(Intent.ACTION_BOOT_COMPLETED)) {
// Register your reporting alarms here.
}
}
}
You'll need to add the following permission to your AndroidManifest.xml for that to work. Don't forget to register your alarms when you run the app normally, or they'll only be registered when the device boots up.
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>

Here is a semi-different way to keep the service going forever. There is ways to kill it in code if you'd wish
Background Service:
package com.ex.ample;
import android.app.Service;
import android.content.*;
import android.os.*;
import android.widget.Toast;
public class BackgroundService extends Service {
public Context context = this;
public Handler handler = null;
public static Runnable runnable = null;
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onCreate() {
Toast.makeText(this, "Service created!", Toast.LENGTH_LONG).show();
handler = new Handler();
runnable = new Runnable() {
public void run() {
Toast.makeText(context, "Service is still running", Toast.LENGTH_LONG).show();
handler.postDelayed(runnable, 10000);
}
};
handler.postDelayed(runnable, 15000);
}
#Override
public void onDestroy() {
/* IF YOU WANT THIS SERVICE KILLED WITH THE APP THEN UNCOMMENT THE FOLLOWING LINE */
//handler.removeCallbacks(runnable);
Toast.makeText(this, "Service stopped", Toast.LENGTH_LONG).show();
}
#Override
public void onStart(Intent intent, int startid) {
Toast.makeText(this, "Service started by user.", Toast.LENGTH_LONG).show();
}
}
Here is how you start it from your main activity or wherever you wish:
startService(new Intent(this, BackgroundService.class));
onDestroy() will get called when the application gets closed or killed but the runnable just starts it right back up.
I hope this helps someone out.
The reason why some people do this is because of corporate applications where in some instances the users/employees must not be able to stop certain things :)
http://i.imgur.com/1vCnYJW.png
EDIT
Since Android O (8.0) you have to use JobManager for scheduled tasks. There is a library called Android-Job by Evernote which will make periodic background work a breeze on all Android versions. I have also made a Xamarin Binding of this library.
Then all you need to do is the following:
In your application class:
public class MyApp extends Application {
#Override
public void onCreate() {
super.onCreate();
JobManager.create(this).addJobCreator(new MyJobCreator());
}
}
Create the following two classes YourJobCreator and YourSyncJob(Where all the work will be done. Android allocates time for all the background jobs to be run. For android versions < 8.0 it will still run with an Alarm manager and background service as per normal)
public class MyJobCreator implements JobCreator {
#Override
#Nullable
public Job create(#NonNull String tag) {
switch (tag) {
case MySyncJob.TAG:
return new MySyncJob();
default:
return null;
}
}
}
public class MySyncJob extends Job {
public static final String TAG = "my_job_tag";
#Override
#NonNull
protected Result onRunJob(Params params) {
//
// run your job here
//
//
return Result.SUCCESS;
}
public static void scheduleJob() {
new JobRequest.Builder(MySyncJob.TAG)
.setExecutionWindow(30_000L, 40_000L) //Every 30 seconds for 40 seconds
.build()
.schedule();
}
}

You should schedule your service with alarm manager, first create the pending intent of service:
Intent ii = new Intent(getApplicationContext(), MyService.class);
PendingIntent pii = PendingIntent.getService(getApplicationContext(), 2222, ii,
PendingIntent.FLAG_CANCEL_CURRENT);
Then schedule it using alarm manager:
//getting current time and add 5 seconds to it
Calendar cal = Calendar.getInstance();
cal.add(Calendar.SECOND, 5);
//registering our pending intent with alarmmanager
AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
am.set(AlarmManager.RTC_WAKEUP,cal.getTimeInMillis(), pi);
this will launch your service after 5 seconds of current time. You can make your alarm repeating.

You can use Alarm Manager to start Service at specified time and then repeat alarm in specified interval. When alarm goes on you can start service and connect to server and make what you want

Disable update on battery percentage

I have a service that performs background updates.
I want to give the user the the option to disable the updates when their battery percentage reaches a certain level.
From my research, I'm going to use a receiver in the onCreate method of my Service class, eg:
public class MainService extends Service
{
#Override
public void onCreate()
{
this.registerReceiver(this.BatInfoReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
}
private BroadcastReceiver BatInfoReceiver = new BroadcastReceiver(){
#Override
public void onReceive(Context arg0, Intent intent) {
int level = intent.getIntExtra("level", 0);
}
};
}
I'm assuming that the best practice is to leave the service running, check the battery level in the service, and not perform the CPU-intensive code, based on the percentage?
I don't actually need to stop the service itself and start it up again, based on the battery percentage?
UPDATE:
This seems to be a better solution, but not 100% sure. I registered a BroadcastReceiver in the AndroidManifest:
<receiver android:name="BatteryReceiver" />
Then created a BroadcastReceiver:
public class BatteryReceiver extends BroadcastReceiver
{
#Override
public void onReceive(final Context context, final Intent intent)
{
final int currentBatteryPercent = intent.getIntExtra("level", 0);
final int disableBatteryPercent = Integer.parseInt(PreferenceManager.getDefaultSharedPreferences(context).getString("batteryPercent", 0);
//AlarmReceiver is the service that performs the background updates
final ComponentName component = new ComponentName(context, AlarmReceiver.class);
if (currentBatteryPercent < disableBatteryPercent)
{
context.getPackageManager().setComponentEnabledSetting(component, PackageManager.COMPONENT_ENABLED_STATE_DISABLED , PackageManager.DONT_KILL_APP);
}
else
{
context.getPackageManager().setComponentEnabledSetting(component, PackageManager.COMPONENT_ENABLED_STATE_ENABLED , PackageManager.DONT_KILL_APP);
}
}
}

That's right. What you will typically do is schedule some broadcast intent for an update (perhaps through an AlarmManager). When you get the notification that there is a low battery, you will stow this away in your service, and then before doing an update, check to ensure that the battery isn't too low. here is a good tutorial of watching the battery level. You shouldn't do much when handling this intent, just stick the battery level somewhere and (before doing an update) make sure it's appropriately "full."
Your update is a really bad way to stop an app. In general, asking the package manager to stop your component is much more of a hack than a solution. Instead, you should move some code into the component that actually does the updating, and store / update the information for the battery info there. Before you do an update, you check the battery level and don't proceed unless it's at a level where you feel comfortable updating the app. Using a broadcast receiver is fine, but you need to store the level somewhere (perhaps a sharedprefs). Instead, this is why putting the receiver within the service where you do the updating is probably best.

Is it possible to manage this requirement with a broadcastReceiver instead of running a service continuously ?
public void onReceive(final Context context, final Intent intent) {
if(intent != null && intent.getAction() != null) {
String action = intent.getAction();
if(action.equals(Intent.ACTION_BOOT_COMPLETED)) {
// Set alarm
}
else if(action.equals(Intent.ACTION_BATTERY_LOW)) {
setLocationAlarmReceiverEnabled(context, false);
}
else if(action.equals(Intent.ACTION_BATTERY_OKAY)) {
setLocationAlarmReceiverEnabled(context, true);
}
}
}

Alarm Manager Reliability

I've been struggling with this problem for days. I've also checked the documentation and several topics but didn't find any solution / explanation.
I am testing my application on LG p500 but I did a few test on Droid too and I get the same result.
My application uses AlarmHandler to schedule alarm. The application works correctly on the emulator and also on the device until the device has enough free memory.
When I start several other applications on the device and the memory is low the alarm will not fire anymore. As soon as I stop the "other" application the alarm works fine again.
Let me report the test and the result.
I set an alarm on my application 10 minute later.
I start several application (browser, google map, gmail, K9Mail,....)
I start the catlog to see the log of my application
Wait 15 minute without working on the phone
After 10 minutes the alarm should be fired but nothing happen until I wakeup my phone pressing a button
When I wake-up my phone the alarm immediatly fires and all the notificatin happen.
I stop the "other" application I previously started (browser, google map,...)
Set again an alarm 10 minute later
I start the catlog to see the log of my application
Wait without working on the phone
10 minutes later the alarm fires and I get notified.
I did this test several time and I get the same result.
Then I tried to set an alarm using the "Catch" application I previously downloaded from the market and I get the same behaviour so it looks like this is not a problem of my application.
Looking at the log of my application I do not see any error / exception but it looks like that when the system is low on memory something happen and the broadcast receiver does not start until the phone is waked up throught the keyboard. As soon as I wake-up the phone the receiver start and all the notification happen.
Here the code I used:
The Receiver:
public class NotificationReceiver extends BroadcastReceiver
{
public static final String LOG_TAG = "YAAS - Notification Receiver";
#Override
public void onReceive(Context context, Intent intent)
{
ScheduleActivityService.acquireStaticLock(context);
Log.i(LOG_TAG, "Received alarm - id: " + intent.getIntExtra("id", -1));
Intent intent2 = new Intent(context, ScheduleActivityService.class);
intent2.putExtra("id", intent.getIntExtra("id", -1));
context.startService(intent2);
}
}
The Service
public class ScheduleActivityService extends Service
{
public static final String LOCK_NAME_STATIC="it.hp.yaas.AppService.Static";
public static final String LOG_TAG = "YAAS - ActivityService";
private static PowerManager.WakeLock lockStatic = null;
private final IBinder mBinder = new LocalBinder();
public class LocalBinder extends Binder
{
public ScheduleActivityService getService()
{
return ScheduleActivityService.this;
}
}
#Override
public IBinder onBind(Intent intent)
{
return mBinder;
}
public static void acquireStaticLock(Context context) {
getLock(context).acquire();
}
synchronized private static PowerManager.WakeLock getLock(Context context)
{
if (lockStatic == null)
{
PowerManager mgr = (PowerManager)context.getSystemService(Context.POWER_SERVICE);
lockStatic = mgr.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, LOCK_NAME_STATIC);
lockStatic.setReferenceCounted(true);
}
return(lockStatic);
}
/**
* This method is called when an alarm fires that is its alarm time is reached.
* The system assume that the alarm fired match the alarm time of the first
* activity.
* #param intent intent fired
* #param flag
* #param startId
*/
#Override
public int onStartCommand(Intent intent, int flag, int startId)
{
super.onStartCommand(intent, flag, startId);
try {
Log.i(LOG_TAG, "Alarm fired: " + startId + " - id: " + intent.getIntExtra("id", -1));
AlarmHandler.getInstance().onAlarmFired(intent.getIntExtra("id", -1));
}
finally { getLock(this).release(); }
return START_STICKY;
}
#Override
public void onDestroy()
{
super.onDestroy();
Log.i(LOG_TAG, "Destroy");
}
}
An piece of code from AlarmHandler, the routine called to schedule the alarm:
public synchronized void onAlarmFired(int alarmId)
{
scheduledAlarmId = -1;
Alarm alarmFired = pop();
if (alarmFired == null) return;
Log.i(LOG_TAG, "onAlarmFired (Alarm: " + alarmFired + ") at (time: " + Utilities.convertDate(new Date(), "HH:mm:ss") + ")");
notifyAlarmListener(alarmFired);
if (alarmFired.reschedule(null) != null) add(alarmFired);
Alarm alarm = peek();
if (alarm != null && scheduledAlarmId != alarm.getId()) scheduleEvent(alarm);
}
/**
* Schedule an alarm through AlarmManager that trigger next activity notification
* #param alarm alarm to be scheduled
*/
private void scheduleEvent(Alarm alarm)
{
Log.i(LOG_TAG, "scheduleEvent - (Alarm: " + alarm + ")");
Intent intent = new Intent(context, NotificationReceiver.class);
intent.putExtra("id", alarm.getId());
// In reality, you would want to have a static variable for the request code instead of 192837
PendingIntent sender = PendingIntent.getBroadcast(context, 192837, intent, PendingIntent.FLAG_UPDATE_CURRENT);
// Get the AlarmManager service
AlarmManager am = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
am.set(AlarmManager.RTC_WAKEUP, alarm.getTime().getTime(), sender);
scheduledAlarmId = alarm.getId();
}
And finally this is a piece of Manifest file:
<activity android:name=".ListActivity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".EditActivity"/>
<activity android:name=".SettingsActivity"/>
<service android:name="ScheduleActivityService"
android:label="YAAS Service"/>
<receiver android:name="NotificationReceiver" />

Are you sure your process doesn't get killed when you start all those applications? If it does, the alarms you set will die with it. It's not exactly clear who and when schedules the alarm in your code, but if it's the service, since it's sticky, it will eventually gets re-started, and you will get an alarm at some point (when you wake the device).
An easy way to check what alarms are registered at different points of your testing:
# adb shell dumpsys alarm

My code is very similar to yours on an alarm app that I wrote and use regularly. I haven't been able to reproduce the problem that you describe. I can't seem to get my phone to a state of extremely low memory. I opened every app I have installed and still have 260M free on my HTC Rezound.
As a safeguard in my app I used alarmmanager.setRepeating() instead of .set(). I set the repeat interval to 20 seconds. I passed the alarm ID as an intent extra just as you have. When my service starts it immediately cancels the pending intent using the alarm ID. My logic here is that if for any reason my alarm fails it will continue to try every 20 seconds until it succeeds.

In your code is AlarmManager.set(), which is not guaranteed to fire at the time you specify. It may fire 30 minutes or even 6 hours later, which I've seen happen on devices like the Xiaomi POCO F1.
Instead use AlarmManager.setExact() to schedule your code to run at a specific time.
Android 12 introduces an exact alarms permisison. If you don't want to deal with that, you can instead use AlarmManager.setWindow() with a small window like 15 minutes.

Lock android app after a certain amount of idle time

My android application requires a password to be entered in the first activity. I want to be able to automatically send the application back to the password entry screen after the application has been idle for a fixed amount of time.
The application has multiple activities, but I would like the timeout to be global for all activities. So, it wouldn't be sufficient to create a timer thread in the onPause() method of an Activity.
I'm not sure what the best definition for the application being idle is, but no activities being active would be sufficient.

I know another answer is accepted already, but I came across this working on a similar problem and think I'm going to try an alternate much simpler approach that I figured I may as well document if anyone else wants to try to go down the same path.enter code here
The general idea is just to track the system clock time in a SharedPreference whenever any Activity pauses - sounds simple enough, but alas, there's a security hole if that's all you use, since that clock resets on reboot. To work around that:
Have an Application subclass or shared static singleton class with a global unlocked-since-boot state (initially false). This value should live as long as your Application's process.
Save the system time (realtime since boot) in every relevant Activity's onPause into a SharedPreference if the current app state is unlocked.
If the appwide unlocked-since-boot state is false (clean app start - either the app or the phone restarted), show the lock screen. Otherwise, check the SharedPreference's value at the lockable activity's onResume; if it's nonexistent or greater than the SharedPreference value + the timeout interval, also show the lock screen.
When the app is unlocked, set the appwide unlocked-since-boot state to true.
Besides the timeout, this approach will also automatically lock your app if your app is killed and restarts or if your phone restarts, but I don't think that's an especially bad problem for most apps. It's a little over-safe and may lock unecessarily on users who task switch a lot, but I think it's a worthwhile tradeoff for reduced code and complexity by a total removal of any background process / wakelock concerns (no services, alarms, or receivers necessary).
To work around process-killing locking the app regardless of time, instead of sharing an appwide singleton for unlocked-since-boot, you could use a SharedPreference and register a listener for the system boot broadcast intent to set that Preference to false. That re-adds some of the complexity of the initial solution with the benefit being a little more convenience in the case that the app's process is killed while backgrounded within the timeout interval, although for most apps it's probably overkill.

I dealt with this by using the AlarmManager to schedule and cancel timeout action.
Then in the onPause() event of all of my activites, I schedule the alarm. In the onResume() event of all of my activities, I check to see if the alarm goes off. If the alarm went off, I shutdown my app. If the alarm hasn't gone off yet I cancel it.
I created Timeout.java to manage my alarms. When the alarm goes off a intent is fired:
public class Timeout {
private static final int REQUEST_ID = 0;
private static final long DEFAULT_TIMEOUT = 5 * 60 * 1000; // 5 minutes
private static PendingIntent buildIntent(Context ctx) {
Intent intent = new Intent(Intents.TIMEOUT);
PendingIntent sender = PendingIntent.getBroadcast(ctx, REQUEST_ID, intent, PendingIntent.FLAG_CANCEL_CURRENT);
return sender;
}
public static void start(Context ctx) {
ctx.startService(new Intent(ctx, TimeoutService.class));
long triggerTime = System.currentTimeMillis() + DEFAULT_TIMEOUT;
AlarmManager am = (AlarmManager) ctx.getSystemService(Context.ALARM_SERVICE);
am.set(AlarmManager.RTC, triggerTime, buildIntent(ctx));
}
public static void cancel(Context ctx) {
AlarmManager am = (AlarmManager) ctx.getSystemService(Context.ALARM_SERVICE);
am.cancel(buildIntent(ctx));
ctx.startService(new Intent(ctx, TimeoutService.class));
}
}
Then, I created a service to capture the intent generated by the alarm. It sets some global state in my instance of the application class to indicate that the app should lock:
public class TimeoutService extends Service {
private BroadcastReceiver mIntentReceiver;
#Override
public void onCreate() {
super.onCreate();
mIntentReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if ( action.equals(Intents.TIMEOUT) ) {
timeout(context);
}
}
};
IntentFilter filter = new IntentFilter();
filter.addAction(Intents.TIMEOUT);
registerReceiver(mIntentReceiver, filter);
}
private void timeout(Context context) {
App.setShutdown();
NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
nm.cancelAll();
}
#Override
public void onDestroy() {
super.onDestroy();
unregisterReceiver(mIntentReceiver);
}
public class TimeoutBinder extends Binder {
public TimeoutService getService() {
return TimeoutService.this;
}
}
private final IBinder mBinder = new TimeoutBinder();
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
}
Finally, I created a subclass of Activity that all of my app's activities subclass from to manage locking and unlocking:
public class LockingActivity extends Activity {
#Override
protected void onPause() {
super.onPause();
Timeout.start(this);
}
#Override
protected void onResume() {
super.onResume();
Timeout.cancel(this);
checkShutdown();
}
private void checkShutdown() {
if ( App.isShutdown() ) {
finish();
}
}
}
Using onPause and onResume to start and stop the timeout gives me the following semantics. As long as one of my application's activities is active, the timeout clock is not running. Since I used an Alarm type of AlarmManager.RTC, whenever the phone goes to sleep the timeout clock runs. If the timeout happens while the phone is asleep, then my service will pick up the timeout as soon as the phone wakes up. Additionally, the clock runs when any other activity is open.
For a more detailed version of these, you can see how I actually implemented them in my application https://github.com/bpellin/keepassdroid

Check out how OpenIntents Safe implements this functionality.

This has been a really helpful post for me. To back the concept given by #Yoni Samlan . I have implemented it this way
public void pause() {
// Record timeout time in case timeout service is killed
long time = System.currentTimeMillis();
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.Editor edit = preferences.edit();
edit.putLong("Timeout_key", time);// start recording the current time as soon as app is asleep
edit.apply();
}
public void resume() {
// Check whether the timeout has expired
long cur_time = System.currentTimeMillis();
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
long timeout_start = preferences.getLong("Timeout_key", -1);
// The timeout never started
if (timeout_start == -1) {
return;
}
long timeout;
try {
//timeout = Long.parseLong(sTimeout);
timeout=idle_delay;
} catch (NumberFormatException e) {
timeout = 60000;
}
// We are set to never timeout
if (timeout == -1) {
return;
}
if (idle){
long diff = cur_time - timeout_start;
if (diff >= timeout) {
//Toast.makeText(act, "We have timed out", Toast.LENGTH_LONG).show();
showLockDialog();
}
}
}
Call pause method from onPause and resume method from onResume.