Develop Reference

Android: Listen for starting applications

I am looking for a way to listen for starting applications/activities.
I guess many of You know the application "Tasker" which achieves exactly that. If a chosen applications gets launched, a specific task starts.
Now I wonder how to achieve that? I could start a Service, but which method should I use?
I noticed that Tasker asks for a permission before using this method. The application redirects me to the Accessibility Settings tab where I can enable Tasker with the notification: "Tasker wants permission to: Monitor your actions - Allows TalkBack to know when you are using an app"
Any suggestions?
Edit:
I found out that an AccessibilityService is used. Now my problem is, how do I specify all installed packages to this Service? I know that it's possible to specify packages one by one but how do I select all?

you can use getRunningTasks Method
ActivityManager am = (ActivityManager) mContext
.getSystemService(Activity.ACTIVITY_SERVICE);
String packageName = am.getRunningTasks(1).get(0).topActivity
.getPackageName();
Note This method was deprecated in API level 21. you can try this also.

Can I use android app to track user activities?

I wish to know is it possible to write an android app that when it runs at the background, it can track user activities?(Such as what other app did the user used, what phone number did user dial, the GPS location for user, etc) Cause I am not sure can a single android app react to other application, does anyone know the answer? Thanks

In the general case, no, you can't. And users would probably prefer it so.
Once this has been said, there are certain partial solutions. Sometimes the system is so helpful that it will publish Intents reflecting user actions: for example when the user uninstalls an app -- with the caveat that you don't get that intent on the app itself being uninstalled.
It used to be the case that before Jelly Bean (4.1) apps could read the log that other applications publish and try to extract info from there, but it was a cumbersome, error prone, ungrateful task. For example, the browser shows nothing when it navigates to a certain page. You may read the logs for a while with adb logcat to get a feeling of what was possible and what isn't. This action requires the relevant permission, which cannot be held by regular apps now.
Thanks to #WebnetMobile for the heads up about logs and to #CommonsWare for the link, see the comments below.

Yes you can.
You can look here for instance about phone info:
Track a phone call duration
or
http://www.anddev.org/video-tut_-_querying_and_displaying_the_calllog-t169.html
There is a way to let Android and users know you are using and accessing their data for them to determine if they will allow it.
I am unsure you can simply access any app, but in theory if you know how to read the saved files that might be possible.
For instance Runtime.getRuntime().exec("ls -l /proc"); will get you the "proc" root folder with lots of data you might need there. This might have been changed, I am not sure, and I also don't know what you need.
Perhaps to get running process try:
public static boolean getApplications(final Context context) {
ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<RunningTaskInfo> tasks = am.getRunningTasks(1);
}
For this to work you should include this in your AndroidManifest.xml
<uses-permission android:name="android.permission.GET_TASKS" />
See more about it: http://developer.android.com/reference/android/app/ActivityManager.html#getRunningAppProcesses%28%29

You certainly could but I think reporting that data back to you, unbeknownst to the user, via the internet, would be considered spyware and almost certainly illegal in most jurisdictions.

Fortunately spying users at that level should not be possible. Certain features can be achieved with abusing bugs in android which sooner than later will be fixed. I see absolutely no reason for you to know what number I am calling and where I've been lately. It's basically none of your business.

check to see if an application is a service or contentprovider

I am writing an application to add all our apps to the homescreen of our devices. I need it to skip the apps that are services or contentproviders that just run in the background and are never "launched" by the user.
Any ideas? Right now i am specifying the apps, but would like to have it more automated.
Thanks!

See this thread for information on finding launchable Intent instances from the package manager.

Change permissions of another application on Android (rooted)

I see a couple threads on this, but none really speak to what I would like to do. I am trying to write an application that will deny another application the ability to connect to the internet (IE Firewall). Based on algorithms I am creating it will determine that application as being malicious. The app would be on a rooted phone. I would then like to either
Strip all permissions from the Application
Deny it specific permissions (Internet Access)
Force Uninstall that application.
I know there are several programs already out there, but I would like to code this myself :]]
With that being said could anyone point me in the right direction?
Thank you!
EDIT: So I have found this:
public static void killRunningPackage(final Context context, String packageName)
{
ActivityManager activityManager = (ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE);
activityManager.killBackgroundProcesses(packageName);
}
What argument do I pass in for a context? I looked at contexts online but I didnt really understand them

Build Perspective
Even with a rooted phone, because this is handled by the frameworks, I highly doubt that you can achieve something like this.
Specifically unless you have the source and can compile the source of a new phone, you cannot do this.
SDK Perspective
Also another thing about this is you can't "strip" an application of its permissions BECAUSE its in the Manifest.xml which gets embedded into the .apk of an application, which is a binary and is registered with the PackageManager.
This is far beyond the scope of the SDK.
What you CAN do is kill an application if it isn't to your liking. The PackageManager would be your best option, however; that is as far as you can go.
Update
Check this out:
http://android.amberfog.com/?p=98

Listen to ActivityManager events?

is it possible somehow to listen to the events of the ActivityManager, e.g. when activities are started? Does the ActivityManager send broadcasts? I havn't found anything indicating that it does.
What I basically need to do: I want my app to launch one of my activities whenever a certain (thirdparty) app is launched/takes focus. Problem is this needs to happen before the thirdparty app is actually displayed.
What I have tried so far as workarounds:
Logcat output: I query logcat every 0.8s (filtered to show ActivityManager events only) but this eats up to many ressources
getRunningTasks: Slows down the phone a lot too and is not very safe, as an activity might be running but not currently in focus
Any ideas?

I suppose there is no actually other legacy way to handle glabal system state, only
(ActivityManager)getSystemService(Context.ACTIVITY_SERVICE);
ActivityManager.getRecentTasks() - Return a list of the tasks that are currently running, with the most recent being first and older ones after in order.
For details check docs
Perhaps though Android is a Linux you can run system tools like
Runtime.getRuntime().exec("ps -aux | grep smth")
But I think it would be hard to detect particular java application.

I think you can use the launch mode to determine which activity to launch to top level. Please check the question: Android singleTask or singleInstance launch mode?. Maybe it will help you.

I had a look in the android source, but there doesn't seem to be any events broadcasted.
https://android.googlesource.com/platform/packages/providers/ApplicationsProvider