Develop Reference

How to lock (other) apps with password?

I've seen some "app locking" solutions in the Google Play store and I was wondering how those apps work. I'd like to build something similar.
I realize that this might require some special permission or maybe request the app to be added as device administrator.
Is there some broadcast that is triggered just before an app is launched that I can intercept and do some action (e.g. launch an activity that will request the user to fill a password)? I've read some lengthy discussions how this is not a good idea and the only idea is to have a background service that will continuously poll the running processes and check for changes, but I think retrieving this list every second and checking it for chances is not good for the battery and I think other app locking apps out there must be using a different approch.
If possible, without the need for a rooted phone.

Disabling "Force Stop" Button in Android

Okay, I'm pretty sure that this is not possible but a client had asked me to do so in one of our Android application we developed for her.
What she had wanted is that if our application is running, and user navigate to:
Settings > Manage Application > [Our Application]
, the button for "Force Stop" is disabled.
Is this possible? If it is possible, could someone point me out which way I should walk, or if it is not possible, how, using a valid argument based on facts, should I break the news to her.
Update:
She just sent me a screenshot that, in her opinion, validates her request that there's an Android application that disables "Force Stop" button. How am I supposed to explain this to her?

How to disable the "Force Stop" button
Short answer: Use the Device Administration API.
How to explain this to my client?
Show this to your client. It is a nice slideshow providing an easy-to-understand overview of the Device Administration API and its uses.
How do I demonstrate that it works?
Yes, back to your job. Use the API link provided above and the Api Demos included in Google's sample
collection to figure out how to integrate this into your app.
Build the demo and run it on your device.
Choose API Demos->App->Device Admin->General->Enable admin.
Choose Activate once the Device Administration API prompts you with its enabling screen.
Exit the app and attempt to manage the app via your device's settings menu (specifics for this step varies by device).
When viewing the Api Demo's "app info" screen, you should see both Force Stop and Uninstall are disabled.
How do I do this in my own app?
Review DeviceAdminSample.java in the Api Demos app for inspiration. You will need the following:
The following code is what brings up the activation screen:
// Launch the activity to have the user enable our admin.
Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, mDeviceAdminSample);
intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION,
mActivity.getString(R.string.add_admin_extra_app_text));
startActivityForResult(intent, REQUEST_CODE_ENABLE_ADMIN);
However, there are a few other pieces you will need to get this to work:
A broadcast receiver that derives from DeviceAdminReceiver.
Entries in your manifest file that refer to the above broadcast receiver.
Permissions in your manifest for using the Device Administrator API.
An xml file stating what policies your app can access.
All of this can be found in the above links. Good luck with your client!

This is not remotely possible, for great reason.
You should tell her that making this possible would be a huge security disaster. Imagine what would happen if you could create apps which just ate at your processor time by holding a wake lock, and you couldn't kill them. This would be horrible.
In general, if you're wondering if you can modify the "extra-app" behavior of the device, the answer is usually *no*. You should take the viewpoint that nothing on the device is yours to control besides your app and (to a limited extent) the resources to which you're granted access.
No other app has this kind of control, so it's not reasonable to expect that your client's would either. However, the fact that she's asking for this control usually implies something else: that they are worried the user will stop the app and then something bad will happen (the locations will stop being synced, data will stop being sent out to the net, etc...). This would imply that you should look into improving the resilience of the app to different situations. Remember, your app can even be killed off at any time by Android (for example, in the case of low memory).

I think the device screen shot has confused us. Even I can show my application that is installed on the device and the "Force Stop" button is disabled. Where as I have not done any thing specific to that.
The reason of the "Force Stop" button being disabled is, that particular application is NOT running currently. Hence there is not meaning in having the button enabled.
#Rhama you can ask your client to start the application once, press the home button of the device, and goto the settings and see. Surely the "Force Stop" button will be enabled this time.
Regards,
Rajan

From ICS, disabling Force stop is possible. If your app has an active device admin then the framework will not allow user to kill the process

Hey I think it is quite possible to disable the "Force Stop" button...check Kaspersky
Parental Control from the market it is doing the same.
Its service is running in the background then also the force stop button is disabled.
The application service is running in background

you can disable the forcestop when the app has admin rights. but soon as those admin rights are revoked then it is back to normal. however in android 4, an application called applock (domobile) was able to prevent that by asking a password when you tried to change admin rights. It could only be done by installing an extra program that applock asked you to. And I guess this might even be seen as a security flaw, infact it no longer works in Android 5.

Application that keeps itself on top, and re-launch itself when closed

I need to "lock" a user into an application. The device's sole purpose is to use this application, and so it is not feasible to allow the user to navigate the device for any other reason. What is the best way to make sure that the applications Activitys are always in the foreground, and if not, launch the main Activity?
Now I know this goes against everything about the typical Android application development, but these devices are going to be specifically used for this one application.
What is the best way to determine if any of the applications Activitys are in the foreground, and launch one if not?

What is the best way to make sure that the applications Activitys are always in the foreground, and if not, launch the main Activity?
You don't.
Make your activity be the home screen, and they can't go anywhere. And roll your own firmware, so that the user can't safe-boot the device and remove your home screen.

I will probably use a service which gonna check using a flag as example for a living activity.
Look here for more detail about how to do : http://developer.android.com/guide/topics/fundamentals.html

See the answer to this question: basically you must implement a second app that captures home intents and simply re-launches your primary application if it is ever closed.

In reference to what CommonsWare was saying, you could actually partially brick the device. I've done it on accident where I've bricked the recovery menu, but not the actual regular boot. This is a terrible idea of course and should not be used practically.

Android phone as a dedicated device

We want to use Android mobile for dedicated application. Can somebody suggest how can we make it happen.
Here are the requirement:
The phone when started, should launch our application., so the user cannot launch any other application. The application will be a 1D barcode reader.
The application should be live as long as the phone is up and running, user cannot close the application at all.
Thanks for your help.
Regards,
Manish

Android after boot is complete sends a bradcast intent:
android.intent.action.BOOT_COMPLETED
if you listen for this intent, you can launch a service that in turn launch your activity.
In the Activity you have to take care of the user's interactions that explicitly close the activity, like home button, back button and camera button press.
Setting your activity to be full-screen also should prevent the user to use the notification bar to interact with notification like those from market-app that can close your activity.
Finally, your activity can be killed by the system by various and uncatchable reasons: in those cases, the service that first launched your Activity comes in handy, as it can periodically monitor the general state of the application and relaunch components as needed.

Check out the new Android Enterprise solutions for your use case.
https://developers.google.com/android/work/overview
Its well documented. You can either use
Android Management API to provision the devices and apply policies to the device which will be applied to the device using Android's Device Policy Controller (DPC) or,
Use Google Play EMM API and develop your custom DPC
It depends upon your use-case really, but the first solution set should serve your purpose

I'm afraid there's no single answer to this, but you need to work on multiple fronts.
One of these fronts is preventing user from running other applications: for this there are applications sold on Android Market that can put other apps of your choosing behind passcode.
You need to combine this with automatic launch, but I don't yet know how to do that.

How to Lock(Block) an android application from starting / How to stop an android application (service) from starting at boot

I would like to know if there is a way to lock (prevent) an application from starting.
And i also would like to know if there is a way to prevent a service(application) from starting at boot of the device
...i would like to know because i would like to create an anti-malware app.

I know this question is old, but for others stumbling over it:
Autostarts is an application that can disable apps from starting at boot time. It's the best I've found to do that (it isn't resident and doesn't kill processes like a task manager, it actually parses apk packages and reads registered actions and blocks the actions you tell it to). BUT it needs root and hasn't been updated for a while (december 2011). It works on Android 2.3 on which I tested it. Because it was discontinued, I don't know if it works on newer OS versions.
It's commercial now, but that's not the point, you need a peek at the source code.
If you search a bit, you'll be able to find the source code for an older version and see how it implements the blocking system.
I would be very interested in an application that could block certain services. NOT kill, but prevent them from starting in the first place. And the list is quite big: Facebook (OrcaService, MqttPushService, MediaUploadService, BackgroundDetectionService), Twitter, Maps (NetworkInitiatedService), Yahoo Mail Sync, etc. I don't use the features that the services provide, I even disabled some of them in the app interface where possible, but they still pop up and remain resident after exiting the application.

I would like to know if there is a way to lock (prevent) an application from starting.
Not in any supported fashion. Anything that does this is malware, and the techniques for doing it are security holes.
And i also would like to know if there is a way to prevent a service(application) from
starting at boot of the device
The user can boot their phone in safe mode (I forget the exact process, but it's something like holding down the HOME key while turning the phone on).