iOS Multitasking App Launch - objective-c

I developed an app for IPhone and it's posted to itunes for approval. Now when I test the app I found out a strange behavior which I think should be rectified. When I launch app first time, the app launched and when I press home button it closes but when I tap the app icon to open it again it opens where it was last closed.
How can I change the view to first view of the app when it's launched after closing by Home screen button?

If you don't want your app to run in the background you need to set the "Application does not run in background" key in the info.plist file. This means that your app will completely restart every time your user returns to it. Take time to decide if this really is the best move for your app. Allowing users to return to where they left off or remembering information about the last session can be a big plus.
If you do not set the info.plist value like I mention above you can manage the way your app behaves by using the: applicationWillEnterForeground: in UIApplicationDelegate or you could observe UIApplicationWillEnterForegroundNotifications. Read up on all the available notifications and methods available for this in the UIApplication Delegate documentation.

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How can I detect/observe when third party app launches a full screen process?

I would like to build a helper app for gamers, and to build some extra functionality I would like to observe/time certain third party games behaviors, more specifically when the game actually launches the full screen process.
For example: my app is a system tray app, the game has a "launcher" app with lobby and menu screens. Once the game launches the extra process, usually OS X will switch resolutions (optionally) and my App would be notified somehow. Then I can start a timer. Once game match finishes, either the process is closed, or the game is not full screen anymore, my app gets a second notification and I can stop the timer.
Are there official Apple APIs that provide any way to observe/poll for the app going full screen and/or launch additional windows that I can reliably assume it's the actual game screen?
I doubt you're going to find a completely comprehensive solution. There are many ways for apps to achieve a full-screen experience and most don't provide a notification about that fact.
A full-screen app can modify the presentationOptions of NSApplication to hide the Dock and menu bar. Another app can use key-value observing to monitor its application object's currentSystemPresentationOptions property, which will reflect the current system status.
A full-screen app can capture the displays (although Apple discourages this technique). You can try to detect this by calling CGDisplayIsCaptured(), although it's been deprecated since 10.9 with no replacement. It may be possible that, if you register a callback with CGDisplayRegisterReconfigurationCallback(), you'll get called when something captures the display. However, capturing the display is sort of about preventing other processes from noticing such changes, so maybe not. In that case, you'd have to poll. You might also poll for the current display mode; changing the mode is the primary reason why a game would capture the display in the first place.
A full-screen game could also just create a borderless window the size of the screen and set its window level to be in front of the Dock and menu bar (and other apps' windows). There's not really a notification about this. You could detect it using the CGWindowList API, but you would have to poll. For example, you could call CGWindowListCopyWindowInfo(kCGWindowListOptionOnScreenOnly, kCGNullWindowID) and iterate through the dictionaries looking for one the size of the screen and at a window level above kCGStatusWindowLevel.
(You might be able to use the Accessibility API to get a notification when the frontmost window changes, so you'd only have to poll when that happens.)
You cannot observe a notification if there is none. So firstly you need to know if the app you want to observe is actually sending a notification that is observable. You cannot 'hook' into other apps without their planned consent.

how to keep ios app using opentok video chat in foreground

I've integrated opentok ios sdk in my iOS 7 app, it is working fine, except this problem:
During video chat if I don't access iPhone for 5-10 seconds..then my app moves into background, causing viewer at other end to hear only audio. Video is disabled after app goes to background state.
I've observed same thing with their official example
https://github.com/opentok/opentok-ios-sdk/tree/master/samples/OpenTokFullTutorial
How can I avoid my app going to background while video chat is ongoing. Skype is working fine in this case, I want to achieve same thing.
What you want to do is prevent the iPhone from going to sleep. To do this, you cant try this:
[UIApplication sharedApplication].idleTimerDisabled = YES;
Here is iOS documentation on idleTimerDisabled
If you don't want the app going into background at all (like when the user taps on home button), you can opt to kill the app when it's not running instead of having it run in the background. To do that, check out iOS guide on opting out of background execution
If you do not want your app to run in the background at all, you can
explicitly opt out of background by adding the
UIApplicationExitsOnSuspend key (with the value YES) to your app’s
Info.plist file. When an app opts out, it cycles between the
not-running, inactive, and active states and never enters the
background or suspended states. When the user presses the Home button
to quit the app, the applicationWillTerminate: method of the app
delegate is called and the app has approximately 5 seconds to clean up
and exit before it is terminated and moved back to the not-running
state.
Hope that helped!

Save Button Pushes and Location

I am making an app where I need to know
every button that was ever pushed by the user in the app, and when it was pushed, and
where the iPhone has gone (using gps), but there are no cell towers in the area so I can't use that significant location changes method everyone uses.
It seems to me like the Plist method for data saving won't work because I don't want the app to start where it left off, I want it to start at the beginning every time.
Also, if any of you have any idea how I can make my app wake up at certain specific times, and/or how I can make it impossible to exit, that would be awesome. This is for an experiment with the University of Queensland St. Lucio Psych Department and the Grute Eylandt Aborigines.
You can know everything the user does in your app if you want. You could use your own solution with an SQLite database for example, and dispatch the data to a server every once in a while.
The GPS is also easy, you could just track the user with the Core Location framework.
You can't make the app wake at specific times, the best you can do is implement push notifications but it's up to the user to open the app via the notification or by themselves by tapping the app icon on the iPhone home screen.
Otherwise you could set up a local notification just before exiting the application, this is faster and easier to implement then setting up push notifications.
There is also no way to stop the app being closed, that is until iOS 6 comes along with it's accessibility features, you can disable the home button then. But not now.

UIApplicationWillEnterForegroundNotification is not called when app is briefly closed

The UIApplicationDidBecomeActiveNotification and UIApplicationDidBecomeActiveNotification notifications do not seem to be called when the app is only briefly closed.
Specifically: when the app enters the foreground it should check to see if any settings in the settings app were changed. If you go right to the settings app, change something, and come right back, the notifications are sometimes not sent. After closing and reopening the app again, they are called and everything is ok.
Is there a better way to consistently detect when the app enters the foreground? or could something be causing a conflict and keeping these notifications from being sent?
Rather than trying to catch every foreground transition, just watch for changes in the settings, no matter how they happen, by watching NSUserDefaultsDidChangeNotification. See How to get an update NSUserDefault on iOS 4?

OS X Lion: NIB/XIB doesn't seem to get loaded if app is launched as a Startup Item

I have a problem which is driving me nuts.
Suppose you have an app with a window that is set to "Visible at Launch". When you launch the app, the window immediatly appears.
If you add this simple app to the login startup items list, when you log in, the app is automatically launched and you have the window just opened in front of you. This is what was happening in Snow Leopard.
If you repeat the same steps in Lion, as soon as you log-in, the app is launched but the window does not appear.. It seems that the NIB doesn't get loaded.
To make it appear you have to click on the app icon in the dock (even if the app is already launched).
This happens even if you specify [NSApp disableRelaunchOnLogin] according to Apple documentation here.
Things become worst if your app has NSUIElement = 0 and therefore it doesn't have neither an icon in the Dock, nor a Menubar. In this case there's no way to make the window to appear.
Is there a way to obtain the expected behavior of Snow Leopard? Am I missing something?