Check if app is running and kill - android

I was wondering if I can kill app from other app. I mean I want to create application which when I start this application I will check status other application and if app, which name is for example "Startex" is running then I kill "Startex" app and run my second application.

No you can not. Only Android can kill application if it needs memory. In order to do this you should know the PID of the application you want to kill and invoke a syscall at kernel level

If both apps are designed by you then you can have shared user id in both the Apps then you can kill another app here is the way.

This can't be, or at least should never be done. Android itself is supposed to control when an app is no longer required, usually based on needing to free up some memory for another app that may be opened. Google frown upon developers killing the app themselves without letting Android handle it, and likely would never receive any promo place on the play store from Google.

Related

What exactly does "removing an app" from the multitasking list do?

When I remove the app from the multitask list, it doesn't seem to kill the app's processes + services, but when I reopen the app, it starts from the "beginning" such as the homepage. What exactly does removing the app from the multitask list do exactly?
Generally removing an app from your multitask list is the same as quitting an active app (by hitting the back button continuously). The app stops functioning and the background processes linked to the app are killed. But, as you mentioned, it doesn't always happen because there are certain apps that require certain processes to run- for instance, closing an email app still lets it check for email and perform certain functions.
Force stopping your app is what actually kills all background processes as well, however again there are certain apps that still avoid this- this could be because they have some sort of link to the maker of the OS that allows those processes to run. For example, the Gmail app and Android OS both belong to Google, so they probably can decide how their app runs regardless of what you do as an end user.

stopping the user from forcing stop my app

About Android (6.0 to the last version)
I'm developing an app and we want that the user, once he accepts all the terms, don't be able to kill the process or force stop the app. Honestly, I'm completely lost right now, because on the last versions of android, and specially some brands like Xiaomi, we are having a lot of trouble with it, and we don't know how to act right now.
In the case that it could not be possible, could at least get an alert whenever the user is killing the app?
Thanks!!
It is not possible to prevent the user from killing an app. Android is a unique system where the app has no direct control over its lifecycle but the system has. The system can (and will, when required) kill the app or any of its processes at its own will. To make your app aware of these changes, the android framework provides for various callbacks such as onPause, onStop and onDestroy which are called in succession when the user kills the app.
Side Note : There is no guarantee that onDestroy() will be completely executed when the app is killed. Do not place essential code there.
Of course, you can block or try to prevent the user from closing your app by overriding the back, home and recent buttons but it is highly recommended not to do so. Even if you do so successfully, the user has other means to close your app such as rebooting their phone.
So what to do?
You are looking for a kiosk mode app. Kiosk mode is used for single purpose phones such as at a restaurant or for a cab driver. Kiosk mode apps lock down the user to only a specific app (or a specific set of apps).
For normal apps, it is not possible to prevent the user from force closing your app. You can only get alerts by checking for lifecycle changes as described above. Moreover, it is not at all recommended to change the natural behavior of the hardware buttons on android. The user can still find a way to close your app. If your app is doing something really essential which should proceed in the background, consider using a service for that instead. Also, the user can uninstall your app at anytime if they find your app being too intrusive and you won't be able to do anything in that scenario.
Tl;dr: Use kiosk mode to prevent the user from exiting the app. This will only allow the user to access your app(s) in their device.
Usually you cannot! Even if you try to disable some buttons, user can always stop app or restart device. In addition at times, the OS will stop the App. Your responsibility as a programmer is to program around this, and give the user the feel that it never stopped. If you are doing background monitoring, you will need to use service. Users will still be able to stop service. Having said that, you can set your app as a Device Administration app, see here, which may disallow stopping, but unless you are distributing internally to a company, noone will install.

Android App quits automatically if its idle for some hours

I created an new Android app and succeeded in its working. Its all functionality are working fine. While starting it will ask use name and password.
What my problem was "If my Application is idle for some 4 to 5 hours, then automatically it get quit , while restarting its again asking to login"
I need to know how to avoid automatic quit of my app.
I'm sorry if its simple or already asked quetions.
I need to know how to avoid automatic quit of my app.
No, you do not. Simply redirect the user to log in again, or, as #Rasel suggests, persistently cache credentials in a file or database or something.
Android applications do not and must not live forever. Phones have limited RAM. Android will terminate unused applications after a period of inactivity, to free up RAM for other applications. This is perfectly normal, just as it is perfectly normal for a user to close a Web browser after visiting a Web app.
Its completely natural for the android application.Android OS automatically kill the process when it needs to do.So if you want keep your application alive you have to think differently.To keep always running you can use service that will monitor your application states and handle the situation when it prompts for the login info again.
Another option you can write the login information in the shared preference and can clean when user intentionally leave the application.So when starting again if you find the information you can directly prompt to the user without entering the login information

What happens when android app is "killed"

I have an app which has real time push notifications enabled. So my query is whenever any user tries to kill my app using "Advance Task Killer", my app goes into undefined state.
Undefined State: What i mean is my app doesn't gets completely terminated. The screen has data in a inconsistent state.
So is there way where i can take a user to login screen back whenever an app is killed. So that user wont see any undefined state.
Also want to know what happens to my app states after it gets killed so that i can fix the issue.
Help Appreciated.
It depends on the version of the platform. Prior to 2.2, third party applications like ATK could use an API that did the same thing as the "Force Stop" button in manage apps -- this kills all app processes, removes all tasks/activities, unregisters all alarms, removes all notifications, stops all services, etc. Basically make the application not running the same as if it was first installed, except its persistent data is still intact.
Needless to say, this tends to cause misbehavior of applications, so as of 2.2 other applications like ATK can no longer do this to your app. The API they were using is now only able to do the same thing that the out of memory killer does -- kill the application processes but only if they are in the background in a killable state. It can do no more than the normal out of memory killer, so as of 2.2 if your application is misbehaving due to an app like ATK being used on it then this is exposing an actual bug in the app that users will encounter through the normal use of their device.

Detect if an app was uninstalled

Is there a way to get a system notification when an app has been uninstalled?
I would like to maintain a table of all clients' info currently using my app. However, that seems impossible if there is no way to detect this event.
The first solution I can think of is to have an always running service in the background listening for android.intent.action.PACKAGE_REMOVED. But then would that service be killed once the uninstallation process has ended, or would it be stopped just before the process has kicked off? Also even if this is a solution it's has the potential to put off a lot of people when they realise that part of the app is running in the background.
Any suggestions? Thanks!
You could simply do it the other way round and maintain a table of users actively using your app. Just call a webservice at a point in the program that show it is active. If an app isn't used for a certain time mark it as inactive.
The documentation for the PACKAGE_REMOVED action says the following:
The package that is being uninstalled does not receive this Intent.
So you can monitor for other applications being uninstalled but not your own.
So you'll probably need track who is still using your application, not who has stopped using it. If you don't want the overhead of having your own server to do this you could use a free service like Flurry.
From Android document, the app uninstalled by user can't not get
Intent.ACTION_PACKAGE_REMOVE
But we can use other method to implement this feature. We all know that there is a directory named with your package name under the /data/data directory after your app installed by user. If your app is uninstalled by user, the root directory of your app(/data/data/com.example.yourappname) will be removed by system. The remove action happen immediately when user click "uninstall", and the directory will be removed by framework package manager system.
So, we can monitor the existence of your app data directory(which usually /data/data/com.example.yourappname) to detect if your app uninstalled by user.
In order to monitor this directory, we have to fork a detached process from JNI.
In this new fork process, we can use Linux system api inotify(7) or access(3) to determine the existence of app's data directory.
Here is a workable implementation. But it got the permission problem when try to send an intent to start system browser on high version Android device. I have no idea how to bypass this. However the example above is enough for your question.
Hope it will be helpful!
Android doesn't provide an inbuilt function for tracking the app uninstall.
Notification can be used as an alternate way to track the app uninstall. For this send notification on the app and track the status of the notification. Count the number of undelivered notification for a particular time period. If status of undelivered notification doesn't change in that particular time period, then consider that the app has been uninstalled from the device.
For example, i have used a cron script which run every 3 days and check the status of last 10 notifications delivered to the device (2 notifications are sent in a day). If all of these 10 notifications have status "undelivered", then the app is considered to be uninstalled from the device.

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