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Android - onCreate() called despite using SingleTop launch mode

I currently have two activities in my application.
The second activity in the application prompts a notification icon to be presented in the notification bar.
The intent from the first activity to the second uses the FLAG_ACTIVITY_SINGLETOP and the FLAG_ACTIVITY_CLEAR_TOP flags in the intent. The same goes for the intent used in the PendingIntent from the notification.
My aim is that the second activity is only a single activity and only created once, then when the user leaves via the home button and then goes back to the activity via the notification, the instance that was running comes back and onCreate is NOT called.
This approach works on almost all devices, however testing on one device in particular (A Sony Xperia device - 4.0.4) has shown that it doesn't work in all cases.
On the Sony Xperia the onCreate of the second Activity is always called when it is entered into by the user, even from the notification.
I have tried using singleTop in the Manifest as well without success. Is this a bug in the device or am I doing something wrong? Perhaps missing a flag I need or something along those lines?
If anyone wants more specific code or information please let me know and I will post it.

First of all, please note that it is up to Android to kill your Activity when your app is backgrounded. So there is no guarantee that your activity will stay alive while your app is backgrounded.
In any case, in my projects I end up using singleInstance launch mode for activities that only one instance should be running at the same time.
Just try to update your AndroidManifest with singleInstance launch mode for this activity:
<activity
android:name="com.your.package.YourActivity"
android:launchMode="singleInstance"/>

It is possible to make a HoneyComb activity unclosable?

I'm developing a presentation style application for HoneyComb Tablets. At one stage the tablet may be passed around a room for people to interact with. If possible I would like to prevent malicious users from navigating away from the current activity.
So far I have overwritten the onBackPressed() to prevent finishing the activity but users can still press the other buttons on the status bar and also leave the app via notifications that pop up.
Any suggestions or possible solutions?
Thanks

1. Make your activity full screen.
2 Use an alarmManager to trigger your activity from a service on a regular interval say 2or3 second (only if your activity is not foreground). For this use a boolean variable and store it using sharedPreference. this value will be true in onReume and false in onPause or in onStop or in onDestroy. And then only start your activity from your service if the boolean variable is false. Now if your user will press the Home button then AlaramManager kick start your activiy again.
3 Make a special button for finishing your service and activity and for cancel the alarmManager.

As far as I know there is no way to capture the home button press, so this is not possible. Not to mention, it would be a bad ui design decision by the dev team. The home button is there so every Android user has a standard way to exit apps. There would be some extremely malicious apps if there was a way to make the user unable to exit an app.

I'm developing a similar application that runs in a "kiosk" fashion for retail stores. When the application launches, it programmatically hides the system bar so you cannot exit. The system bar is restored when the tablet is rebooted. It requires root/su however.

How to implement an app locker in android?

I am not satisfied with any of the app locker programs for Android that I have found and would like to create my own, but I am having trouble figuring out how to implement the actual lock. How does one go about implementing an app locker for Android?
There are two issues:
Detecting an Intent, usually from the launcher calling startActivity() or from an ad launching the market app (I'm not talking about broadcast intents -- I need to handle explicit Activity Intents).
The permissions for the locker apps I have seen all have "read system log files" and/or "retrieve running applications" which suggests they might use polling to look for app launches. I think I could do this, but I would like to find a better solution if possible.
Preventing the locked app from processing the Intent. I would prefer not to allow the locked app to run at all until the passcode is entered since it is impossible to tell what it might do when it starts up.
When running my current app locker, logcat shows "ActivityManager: Starting activity" first with the Intent for the locked app, then again with the Intent for the app locker, with nothing in between (separated by 10-20ms). If I enter the correct passcode then I see "ActivityManager: moveTaskToBack".
I have experimented with a test app which demonstrates that, using my current app locker, none of the Activity callbacks are invoked if the app is locked and I do not enter the correct passcode. So it appears to be preventing the app from starting (but I don't know how).
I could use ActivityManager.killBackgroundProcesses() to stop an app, but I have no guarantee that the app hasn't already started running by the time it gets "killed".
I might be able to use PackageManager.setApplicationEnabledSetting() to prevent an app from being instantiated, but I don't think that will take care of apps that are already running (which shouldn't be allowed to process new Intents or come to the foreground). I might be able to use killBackgroundProcesses() to stop all running locked processes so they would have to be re-instantiated. But I don't like this approach because other apps could mess with the Enabled settings and defeat the lock.
Optimally, the system would send every Intent to my app for inspection and allow me to stop or let it pass through, but I'm pretty sure that's not possible (at least, not for explicit intents to start activities from a launcher).
Does anyone know how app locker apps are implemented, or have any bright ideas on how it could be done?

I would look into the lifecycle. Once the app in question begins to load, some activity from that package will be added to the forefront activity.
A scan of the changes in forefront activities might do the trick.
http://developer.android.com/reference/android/app/Activity.html#ProcessLifecycle

How to close an application when the Home button is pressed

Hi I have application with more than 20 activities.I want to close my app when Home button is pressed.

There is no notion of "close my app" in Android. Android will get rid of your activities, followed by your process, after some period of inactivity by the user.

You could use the launchMode and clearTaskOnLaunch flags on your root activity from your AndroidManifest.xml:
android:launchMode="singleTask"
android:clearTaskOnLaunch="true"
When you again start your app, all activities will be killed.

You don't want to do System.exit() -- that's not how the Android Activity Lifecycle normally works (read this also).
What you should do is move the App to the background with moveTaskToBack(). Android will then keep your app running in the background, and kill it if it's unused and something needs its resources later.
If you want it to close all of the open Activities when your App is no longer visible, you can set noHist = "True" for all of the child activities (leave the main activity with noHist = "False", though). This will make it where instead of reopening your application on the last Activity they were on, it will open it on the "main" activity (i.e. it will be as if they just restarted the app).
Anyhow, read through the following answers for more information: Close application and launch home screen on Android

I have the same problem. Im writing a banking app and am required, by contract, to log off the user (or exit) when the app is put into background. There are obvious security concerns there.
There are a couple of ways Im looking to do this:
1. Intercept home button (and back button for the root activity) key press events to call logoff and/or finish()
2. In the onStop() method, for every activity, detect whether the activity is being stopped due to a new activity being show - if not, assume app is being put to background so logoff and/or finish()
The first may not work if a notification is brought to the front then the user clicks home (I havent investigated yet). Or maybe there are other ways for an app to be put into the background without pressing these buttons
The second way sounds messy & difficult to maintain
Id welcome any other ideas
Drapes
I know android has been designed this way, but it seems naive to think that apps wouldnt want an applicationOnStop event

Hi guys what I understood is that u need to know when app goes in background and how to detect it and if I am wrong plz correct me----
The user can go in background if ur app does not provide any way by pressing Back key or Home Key.
You need to use methods "dispatchKeyEvent(KeyEvent event)" to get home key event or back key event and after getting the event you can execute your task.
you can even restrict user from pressing any key but u can not control the home key.

StartActivity intent fails when certain apps are running

I am running into a critical conflict of sorts. My app is a remote service which essentially starts an activity when the screen goes to sleep. How it does this is very simple via screen off broadcast receiver and then an explicit intent to start the activity as a new task. The activity is basically in charge of responding to key events and displaying some simple text.
Thanks to a few window flags added in 2.0, activities can do this. They can be created in a way that either puts them on top of the lockscreen, or completely dismiss the lockscreen. This way they basically have focus without the lockscreen having to be dismissed by user. The alarm clock in 2.0 uses the flags to wake up the device and show the alarm dialog. I use them to place my activity when the screen sleeps so the user sees a custom wakeup lockscreen. The reason we create it at screen off is to get rid of lag the user experiences at wakeup involving first seeing the lockscreen, then seeing the activity appear. Also doing it immediately at sleep allows it to have focus so it can handle key events effectively.
The process works perfectly except in certain apps. So far, it seems the bug is consistent while browser (and even dolphin browser) as well as the facebook app are running. The bug never happens in GTalk or Launcher. It is rare but can still be duplicated in the messaging app every so often. I can't figure out why my activity doesn't get created at sleep while these apps are active. My remote service still gets the screen off broadcast and does the startActivity for the explicit intent, and that's all I get in the log. My onCreate is not being called. Instead it gets called when we wake the screen up again.
I have tried, as a control, to hold the partial wakelock starting when my remote service gets created, and the issue persists. So I don't believe it is a problem that the CPU has gone to sleep. Since only these particular apps cause the issue to duplicate, I can't imagine why the activity start fails. What could those apps be doing to interfere with another app's ability to get created? I use singleInstance as the launch mode so that I can ensure that the activity will never be able to be recalled by user process. I want it to go away when user unlocks and it is working fine like this, as long as it is able to be created. The singleInstance ensures I can have the same lockscreen handle an intent to do something specific based on user actions that the remote service monitors.
my source code can be viewed on my project page. http://code.google.com/p/mylockforandroid/source/browse/#svn/trunk/myLock/src/i4nc4mp/myLock
the issue happens to both my CustomLockService and NoLockService variations. These two services will start Lockscreen or ShowWhenLockedActivity and the bug is witnessed. The build illustrating the bug's end result-- user has to try to unlock 3 times due to the bug because on wakeup when the oncreate finally succeeds, user is seeing the activity when normally it would have auto-dismissed thanks to key event logic that also isn't seeming to happen due to the delayed onCreate, so they have to send it to sleep again. Now that the activity is properly done being started, and screen is asleep, the expected functionality happens at next wakeup-- can be downloaded also from the downloads tab.
This seems like an extremely irrational thing to be caused only by specific apps. I am quite baffled and out of ideas for a solution unless I've made some critical mistake in my activity definitions.

The answer is actually a bug in android that has been in review for a while. It has to do with the home key. For some reason start activity calls as new tasks are getting stopped after the home key has recently been launched. I never noticed the connection during the testing of this. The bug was not consistent and the factor of consistency was whether home button had been used during the wake in question
Here is the bug report: http://code.google.com/p/android/issues/detail?id=4536