There is a particular feature of this application, called Forest, I would like to emulate.
Basically you start a timer in the application and you are not to switch out from it.
This timer counts down if the application is in the foreground and/or when the screen is off.
There is a given grace period of approximately 10 seconds where a user can switch out of the app (i.e. press home button). If they do not return within the grace period, the timer ends and the user fails. Else the timer continues counting.
Basically the application has to check if it is the background. If it is, start a 10 second timer. Once this timer expire, set a bit such then when the app is back to foreground, the user continues/fails.
I am unsure how do this as reading the Flutter/Dart documentation, the lifecycle states available in Flutter is abstracted away from us. Would I have to run some background code or trigger an interrupt? I looked at the plugins available but they do not allow for triggers below 15 minutes. How is this achieved in native Android/iOS code?
You can use Android alarm manager. Through which you can run some background task when alarm triggered.
import 'package:android_alarm_manager/android_alarm_manager.dart';
void printHello() {
final DateTime now = new DateTime.now();
final int isolateId = Isolate.current.hashCode;
print("[$now] Hello, world! isolate=${isolateId} function='$printHello'");
}
main() async {
final int helloAlarmID = 0;
runApp(...);
await AndroidAlarmManager.periodic(const Duration(minutes: 1), helloAlarmID, printHello);
}
prints 'Hello world' for every minute roughly even if app ends.
PS: example code provided above was taken from plugin example.
Related
I'm developing Android only app on Flutter. My app needs to call some Web APIs in the background every 30 seconds. The background worker should keep running even if the user or Android OS closes my app's main activity.
I know that doing something in the background too frequently will drain the battery very quickly and it is considered bad practice. But still, I need to do it every 30 seconds.
The target platform of my app is Android 7.0 or higher.
Any ideas how can I implement this in Flutter?
Try to add Timer I have already use Timer (below code) in my app my problem is solved
Timer: A count-down timer that can be configured to fire once or
repeatedly.
Declare Timer inside your class
Timer timer;
int counter = 0;
Create initState() method for timer
#override
void initState() {
super.initState();
timer = Timer.periodic(
Duration(seconds: 30),
(Timer t) => addValue(),
);
}
Create function for addValue it is increased
void addValue() {
setState(() {
counter++;
});
}
your page auto reload every 30 seconds
OR you just use setState method inside your API call function like below
setState(() { });
maybe this is yet another question about WorkManager, but I really can't find a solution...
I'm trying, as the title suggests, to run a periodic work every 15 minutes. Actually in the worker I'm polling some data every minute. After every poll, every almost 1 second I check if the worker is being stopped and if so return, otherwise keep waiting until 1 minute is reached and poll data again.
According to the documentation this should work and indeed it is, until I kill the app from the recent app screen.
Here is the code:
package com.qsea.app.cordova;
import android.content.Context;
import android.os.SystemClock;
import android.util.Log;
import androidx.work.Worker;
import androidx.work.WorkerParameters;
public class ServerListenerWorker extends Worker {
public static final String TAG = "ServerListenerWorker";
public ServerListenerWorker(
Context appContext,
WorkerParameters workerParams
) {
super(appContext, workerParams);
}
#Override
public Result doWork() {
Log.d(TAG, "Doing work");
final long startTime = SystemClock.elapsedRealtime();
final int maxDelta = 840000; // 14 minutes
while (true) {
// I did this to stop this worker until 15 minutes
// and then let the next worker run
if (SystemClock.elapsedRealtime() - startTime >= maxDelta) {
break;
}
// Here I'm polling data, if the polling results in a failure
// I return Result.retry()
// It avoid waiting if it remains only 1 minute until the max time
if (SystemClock.elapsedRealtime() - startTime >= (maxDelta - 60000)) {
break;
}
for (int i = 0; i < 60; i++) {
SystemClock.sleep(950);
// Here it checks if it is stopped
if (isStopped()) {
Log.d(TAG, "Detected stop"); // this is actually never reached
break;
}
}
}
return Result.success();
}
}
And I do as following to start the work
Constraints constraints = new Constraints.Builder().setRequiredNetworkType(NetworkType.CONNECTED).build();
PeriodicWorkRequest periodicWorkRequest = new PeriodicWorkRequest.Builder(ServerListenerWorker.class, 15, TimeUnit.MINUTES)
.addTag(serverListenerWorkerUID)
.setConstraints(constraints)
.build();
WorkManager.getInstance(cordova.getActivity()).enqueueUniquePeriodicWork(serverListenerWorkerUID, ExistingPeriodicWorkPolicy.KEEP, periodicWorkRequest);
I check the correct working of the worker by viewing the log of my server (If I receive the request it is working fine) and it seems to work ok until I close the app. Then it stops running the actual worker and never run a worker again until I reopen the app, where the work seems to be enqueued and resumes right after the app opening.
Am I doing something wrong in the initialization?
I have also <service android:name=".ServerListenerWorker" android:permission="android.permission.BIND_JOB_SERVICE" /> in my AndroidManifest.xml
Is this expected behavior?
I read that chinese ROM have additional restriction to background services and I have a HUAWEI, which seems to be the worst in this. So could it be the device? And if so, how do Facebook, WhatsApp, Instagram and others manage this to work even in these devices?
Let's split this in two different problems.
What are you doing in your workers is battery heavy and would be better if you use a foreground service that notifies the user that your application is running continuously in the background. You can also use WorkManager with the newly introduced support for long-running workers (that under the hood uses a foreground service). More on this in the documentation.
If have a problem with a specific OEMs, please open an issue on the Android issuetracker as this maybe a CDD violation. Google can contact the OEM and request that they fix the ROM. This is going to take time, in the meanwhile, you can take a look at sites like don't kill my app to understand what are the constraints on a specific device and use a library like autostarter to help the user to navigate to the right setting.
BTW, you don't need to be list your workers in the AndroidManifest.xml file
I have an app that should show a notification every 2 hours and should stop if user has already acted upon the notif. Since background services are history now, I thought of using WorkManager ("android.arch.work:work-runtime:1.0.0-beta01") for the same.
My problem is that although the work manager is successfully showing the notifications when app is running, but it won't show notification consistently in the following cases(I reduced the time span from 2 hours to 2 minutes to check the consistency):
when app is killed from the background.
device is in screen off.
state device is in unplugged state(i.e not charging).
By consistency , i mean that the notifications show at least once in the given time span. for 2 minutes time span, the freq of notifications went from once every 4 minutes to completely not show any notification at all. for 2 hours timespan( the timespan that i actually want), its been 4 hours and i haven't got a single notification. Here is the Code i am using for calling WorkManger:
public class CurrentStreakActivity extends AppCompatActivity {
...
#Override
protected void onCreate(Bundle savedInstanceState) {
...
setDailyNotifier();
...
}
private void setDailyNotifier() {
Constraints.Builder constraintsBuilder = new Constraints.Builder();
constraintsBuilder.setRequiresBatteryNotLow(false);
constraintsBuilder.setRequiredNetworkType(NetworkType.NOT_REQUIRED);
constraintsBuilder.setRequiresCharging(false);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
constraintsBuilder.setRequiresDeviceIdle(false);
}
Constraints constraints =constraintsBuilder.build();
PeriodicWorkRequest.Builder builder = new PeriodicWorkRequest
.Builder(PeriodicNotifyWorker.class, 2, TimeUnit.HOURS);
builder.setConstraints(constraints);
WorkRequest request = builder.build();
WorkManager.getInstance().enqueue(request);
}
....
}
Here is the worker class(i can post showNotif(..) and setNotificationChannel(...) too if they might be erroronous):
public class PeriodicNotifyWorker extends Worker {
private static final String TAG = "PeriodicNotifyWorker";
public PeriodicNotifyWorker(#NonNull Context context, #NonNull WorkerParameters workerParams) {
super(context, workerParams);
Log.e(TAG, "PeriodicNotifyWorker: constructor called" );
}
#NonNull
#Override
public Result doWork() {
// Log.e(TAG, "doWork: called" );
SharedPreferences sp =
getApplicationContext().getSharedPreferences(Statics.SP_FILENAME, Context.MODE_PRIVATE);
String lastcheckin = sp.getString(Statics.LAST_CHECKIN_DATE_str, Statics.getToday());
// Log.e(TAG, "doWork: checking shared preferences for last checkin:"+lastcheckin );
if (Statics.compareDateStrings(lastcheckin, Statics.getToday()) == -1) {
Log.e(TAG, "doWork: last checkin is smaller than today's date, so calling creating notification" );
return createNotificationWithButtons(sp);
}
else {
Log.e(TAG, "doWork: last checkin is bigger than today's date, so no need for notif" );
return Result.success();
}
}
private Result createNotificationWithButtons(SharedPreferences sp) {
NotificationManager manager =
(NotificationManager) getApplicationContext().getSystemService((NOTIFICATION_SERVICE));
String channel_ID = "100DaysOfCode_ID";
if (manager != null) {
setNotificationChannel(manager,channel_ID);
showNotif(manager, channel_ID, sp);
return Result.success();
}
else {
return Result.failure();
}
I am using a xiaomi miA2 androidOne device with Android Pie(SDK 28). There are a few other things that are troubling me:
What can i possibly do to know if my WorkManager is running? Other that just wait for 2 hours and hope for a notification. I actually tried something like that, keeping my phone connected to pc and checking android studio's logcat every now and then. It DOES run all the logs when the worker is actually called, but i don't think that's a correct way to test it, or is it?
In the above Code, the setDailyNotifier() is called from the onCreate() every time the app is opened. Isn't it Wrong? shouldn't there be some unique id for every WorkRequest and a check function like WorkManger.isRequestRunning(request.getID) which could let us check if a worker is already on the given task??If this was a case of AsyncTask, then boy we would have a mess.
I have also checked #commonsware's answer here about wakelock when screen is off, but i remember that work manager does use alarm manager in the inside when available. So what am I missing here?
Few comments:
WorkManager has a minimum periodic interval of 15minutes and does not guarantee to execute your task at a precise time. You can read more about this on this blog.
All the usual background limitation you've on newer Android releases are still relevant when you use WorkManager to schedule your tasks. WorkManager guarantees that the task are executed even if the app is killed or the device is restated, but it cannot guarantee the exact execution.
There's one note about the tasks being rescheduled when your app is killed. Some OEM have done modification to the OS and the Launcher app that prevents WorkManager to be able to accomplish these functionality.
Here's the issuetracker discussion:
Yes, it's true even when the phone is a Chinese phone.
The only issue that we have come across is the case where some Chinese OEMs treat swipe to dismiss from Recents as a force stop. When that happens, WorkManager will reschedule all pending jobs, next time the app starts up. Given that this is a CDD violation, there is not much more that WorkManager can do given its a client library.
To add to this, if a device manufacturer has decided to modify stock Android to force-stop the app, WorkManager will stop working (as will JobScheduler, alarms, broadcast receivers, etc.). There is no way to work around this. Some device manufacturers do this, unfortunately, so in those cases WorkManager will stop working until the next time the app is launched.
As of now , i have this app installed for last 8 days and i can confirm that the code is correct and app is working fine. as said by pfmaggi , the minimum time interval for work manager to schedule the work is 15 minutes, so there is a less chance that the WorkManager would have worked as expected in my testing conditions( of 2 minutes ) . Here are some of my other observations:
Like I said in the question that i was unable to recieve a notification for 4 hours even though i have passed the repeat interval as 2 hours. This was because of Flex Time. I passed in the flex time of 15 minutes and now it shows notifications between correct time interval. so i will be marking pfmaggi's answer as correct.
The problem of repeated work request can be solved by replacing WorkManager.getInstance().enqueue(request) with WorkManager.getInstance().enqueueUniqueWork(request,..)
I was still unable to find a way to test the work manager in the way i have described.
I'm trying to implement a convenient-to-use system for handling status bar notifications for android, and i was thinking about the following:
Create a database, where i store when and what to show
Create a service what runs in the background using the 'interval' Service, what the API provides
In that service check if any notification needs to be shown according to the database, then show it.
The only problem is, that, i cannot detect, if i need to start the service or not. I tried these things, but none of them worked well so far:
1.) Save if the service was already started on the local storage:
// Do this on application startup
var isRunning = Ti.App.Properties.getBool("service_running", false);
if(!isRunning)
{
var service = Titanium.Android.createService(...);
service.addEventListener('start', function()
{
Ti.App.Properties.setBool("service_running", true);
});
service.addEventListener('stop', function()
{
Ti.App.Properties.setBool("service_running", false);
});
service.start();
}
This obviously won't work, because the android systems native onStop and onDestroy events will not be dispatched, if the Service doesn't terminates unusually (like the user force stops the app), so the stop event also won't be fired.
2.) Try to access any active service via Titanium.Android.getCurrentService(), but i got an error saying Titanium.Android has no method called getCurrentService(). This is pretty strange, because the IDEs code completion offered me this method.
3.) Use an Intent to clear the previously running Service
var intent = Titanium.Android.createServiceIntent
(
{
url : 'notification/NotificationService.js'
}
);
intent.putExtra('interval', 1000 * 60);
//Stop if needed
Titanium.Android.stopService(intent);
//Then start it
Titanium.Android.startService(intent);
But it seems like i need to have the same instance of Intent, that started the service to stop it, because doing this on application startup, then exiting and restaring it results in multiple Services to run.
At this point i ran out of ideas, on how to check for running services. Please if you know about any way to do this, let me know! Thanks for any hints!
EDIT
Here are the source materials which gave me the idea to try the above methods (maybe only i use them incorrectly):
The local storage: Titanium.App.Properties
The method for accessing running services: Titanium.Android.getCurrentService
The method for stoping a service with an Intent: Titanium.Android.stopService
And the full source for the NotificationHandler "class" and NotificationService.js that I wrote, and their usage: link
Use Bencoding AlarmManager and it will provide all you need to schedule an alarm notification : https://github.com/benbahrenburg/benCoding.AlarmManager
This module provides what you need. It's really easy - just set repeat to daily when sheduling a Notification or Service.
Refer https://gist.github.com/itsamiths/6248106 for fully functional code
I am checking if the service is started then show daily notification or else start service and then show daily notification
var isRunning = Ti.App.Properties.getBool("service_running", false);//get service running bool status
if (isRunning) {
Ti.API.info('service is running');
} else {
Ti.API.info('service is not running');
alarmManager.addAlarmService({
service : 'com.mkamithkumar.whatstoday.DailyEventNotificatoinService',
hour : "08",
repeat : 'daily'
});
}
I come one year late, but maybe this can help others in the future.
We had the same idea: run the service forever and do the checks on every cycle (I must check 20 different communications).
And I had the same problem: how to detect that the service is running, to don't run again to don't duplicate the checks.
To solve that problem, what I did is get the current time on every cycle and save it to store.
Then, before launch a new service, I check if the last execution was to far in time: if true, then the service was stopped, else is running.
Not very elegant, but was the only way I found to avoid the problem of the user killing the app (and the service).
This is my code for the "launcher" of the service. In my case, I test 30 seconds far away:
exports.createAndroidServiceForNotifications = function(seconds) {
var moment = require('alloy/moment');
var diffSeconds = moment().diff(Ti.App.Properties.getString('serviceLastRun', new Date().getTime() - 60000), 'second');
if (diffSeconds > 30) {
var now = new Date().getTime();
var delta = new Date(now + (seconds * 1000));
var deltaMS = delta - now;
var intent = Ti.Android.createServiceIntent({
url : 'notificationsService.js'
});
intent.putExtra('interval', deltaMS);
Ti.Android.startService(intent);
}
};
I have a jQuery Mobile web app which targets iOS and Android devices. A component of the application is a background task, which periodically checks for a.) changes to local data and b.) connectivity to the server. If both are true, the task pushes the changes.
I'm using a simple setTimeout()-based function to execute this task. Each failure or success condition calls setTimeout() on the background task, ensuring that it runs on 30 second intervals. I update a status div with the timestamp of the last task runtime for debugging purposes.
In any desktop browser, this works just fine; however, on iOS or Android, after some period of time, the task stops executing. I'm wondering if this is related to the power conservation settings of the devices--when iOS enters stand-by, does it terminate JavaScript execution? That is what appears to happen.
If so, what is the best way to resume? Is there an on-wake event which I can hook into? If not, what other options are there which don't involve hooking into events dependent on user interaction (I don't want to bind the entire page to a click event just to restart the background task).
Looks like Javascript execution is paused on MobileSafari when the browser page isn't focused. It also seems if setInterval() events are late, they are simply fired as soon as the browser is focused. This means we should be able to keep a setInterval() running, and assume the browser lost/regained focus if the setInterval function took much longer than usual.
This code alerts after switching back from a browser tab, after switching back from another app, and after resuming from sleep. If you set your threshold a bit longer than your setTimeout(), you can assume your timeout wouldn't finish if this fires.
If you wanted to stay on the safe side: you could save your timeout ID (returned by setTimeout) and set this to a shorter threshold than your timeout, then run clearTimeout() and setTimeout() again if this fires.
<script type="text/javascript">
var lastCheck = 0;
function sleepCheck() {
var now = new Date().getTime();
var diff = now - lastCheck;
if (diff > 3000) {
alert('took ' + diff + 'ms');
}
lastCheck = now;
}
window.onload = function() {
lastCheck = new Date().getTime();
setInterval(sleepCheck, 1000);
}
</script>
Edit: It appears this can sometimes trigger more than once in a row on resume, so you'd need to handle that somehow. (After letting my android browser sleep all night, it woke up to two alert()s. I bet Javascript got resumed at some arbitrary time before fully sleeping.)
I tested on Android 2.2 and the latest iOS - they both alert as soon as you resume from sleep.
When the user switches to another app or the screen sleeps, timers seem to pause until the user switches back to the app (or when the screen awakens).
Phonegap has a resume event you can listen to instead of polling for state (as well as a pause event if you want to do things before it is out of focus). You start listening to it after deviceReady fires.
document.addEventListener("deviceready", function () {
// do something when the app awakens
document.addEventListener('resume', function () {
// re-create a timer.
// ...
}, false);
}, false);
I use angular with phonegap and I have a service implemented that manages a certain timeout for me but basically you could create an object that sets the timer, cancels the timer and most importantly, updates the timer (update is what is called during the 'resume' event).
In angular I have a scopes and root scope that I can attach data to, my timeout is global so I attach it to root scope but for the purpose of this example, I'll simply attach it to the document object. I don't condone that because you need should apply it to some sort of scope or namespace.
var timeoutManager = function () {
return {
setTimer: function (expiresMsecs) {
document.timerData = {
timerId: setTimeout(function () {
timeoutCallback();
},
expiresMsecs),
totalDurationMsecs: expiresMsecs,
expirationDate: new Date(Date.now() += expiresMsecs)
};
},
updateTimer: function () {
if (document.timerData) {
//
// Calculate the msecs remaining so it can be used to set a new timer.
//
var timerMsecs = document.timerData.expirationDate - new Date();
//
// Kill the previous timer because a new one needs to be set or the callback
// needs to be fired.
//
this.cancelTimer();
if (timerMsecs > 0) {
this.setTimer(timerMsecs);
} else {
timeoutCallback();
}
}
},
cancelTimer: function () {
if (document.timerData && document.timerData.timerId) {
clearTimeout(document.timerData.timerId);
document.timerData = null;
}
}
};
};
You could have the manager function take a millisecond parameter instead of passing it into set, but again this is modeled somewhat after the angular service I wrote. The operations should be clear and concise enough to do something with them and add them to your own app.
var timeoutCallback = function () { console.log('timer fired!'); };
var manager = timeoutManager();
manager.setTimer(20000);
You will want to update the timer once you get the resume event in your event listener, like so:
// do something when the app awakens
document.addEventListener('resume', function () {
var manager = timeoutManager();
manager.updateTimer();
}, false);
The timeout manager also has cancelTimer() which can be used to kill the timer at any time.
You can use this class github.com/mustafah/background-timer based on #jlafay answer , where you can use as follow:
coffeescript
timer = new BackgroundTimer 10 * 1000, ->
# This callback will be called after 10 seconds
console.log 'finished'
timer.enableTicking 1000, (remaining) ->
# This callback will get called every second (1000 millisecond) till the timer ends
console.log remaining
timer.start()
javascript
timer = new BackgroundTimer(10 * 1000, function() {
// This callback will be called after 10 seconds
console.log("finished");
});
timer.enableTicking(1000, function(remaining) {
// This callback will get called every second (1000 millisecond) till the timer ends
console.log(remaining);
});
timer.start();
Hope it helps, Thank you ...
You should use the Page Visibility API (MDN) which is supported just about everywhere. It can detect if a page or tab has become visible again and you can then resume your timeouts or carry out some actions.