Question

I need to develop a service which listen for every activity start.
Must I do something like this?

ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningAppProcessInfo> runningAppProcessInfo = am.getRunningAppProcesses();
for (int i = 0; i < runningAppProcessInfo.size(); i++) {
    Log.v("Proc: ", runningAppProcessInfo.get(i).processName);
}

And do I need to do it every X seconds? Does it affect battery consumption?

Answer 1

As far as I know there is currently no way to listen to an app’s launch, Unless it is the first time that it is launching.
ACTION_PACKAGE_FIRST_LAUNCH (Broadcast Action: Sent to the installer package of an application when that application is first launched (that is the first time it is moved out of the stopped state).

So I guess your solution is the best for this right now.