I am using this code
mViewModel.eventGameFinish.observe(this, { hasFinished ->
if (hasFinished) GameFinished()
})
to observe a LiveData in my Activity. Everything is working fine but when the Activity is not on the screen, which means when onStop() is called. I would like observe to react to LiveData changes at any meaningful stage of the Activity lifecycle. Even though the user might not be using their phone and is using another app, the game should continue running in the background.
Thanks in advance.
P.S. I am new to the LiveData architecture.
You should use observeForever() method. Check this implementation.
Related
I've taken over a project that handles which screen to show first in the "applicationDidBecomeActive" function inside the AppDelegate. This has been causing problems because whenever the app asks for a permission sometimes, not all, it will trigger this block of code and send the user to the incorrect screen. I'm not sure what to do since I've never encountered this before. Any ideas why this is occurring or ways to circumvent this? I've tried adding a flag variable, however, that doesn't seem to work consistently because it looks like it gets un-set before the applicationDidBecomeActive is triggered.
When system notifications such as Permissions are presented, the application is sent to background, or becomes "inactive". When the Permission notification is dismissed, the application becomes "active" again. This would explain why didBecomeActive is triggered.
https://developer.apple.com/documentation/uikit/uiapplicationdelegate/1622956-applicationdidbecomeactive
I've taken over a project that handles which screen to show first in the "applicationDidBecomeActive" function inside the AppDelegate... Any ideas why this is occurring or ways to circumvent this?
The simple answer is: don't do that work in applicationDidBecomeActive(). As you've seen, the application can become inactive and then active again while the app remains in the foreground, so that's not the right state transition for what you're doing. Identify the app state transitions where you really do want to choose a screen. For example, you might want to do it when the app launches, and also when it transitions from background to foreground, so you could use application(_:didFinishLaunchingWithOptions:) and applicationWillEnterForeground(_:). (Obviously, you don't want to put the same code in both places, so put it in a separate method and just call it from those two methods.)
Apple has a document that covers this very topic: Managing Your App's Life Cycle. There's also a lot of information on application states on the UIApplicationDelegate reference page. Both documents include helpful state transition diagrams and descriptions of what the various states mean.
As a solution; you can use the applicationWillEnterForeground(). It's being called before the applicationDidBecomeActive() and not being triggered by permission request.
I'm dealing with a strange situation I want to debug in my Windows Phone 8.1 app, and I'm not sure in which moments OnNavigatedTo is called.
Obviously, it gets called (and I've checked tracing it with the debugger) when you navigate to the view normally.
My doubt arises in other point I want to check, let's call it "You wake up your application and the screen was shut off".
My question is: When you turn on the screen, and you swype the screen protector away, is "OnNavigatedTo" function called or not?
According to some manuals I've read somewhere else, it should.
According to my Debug.Writeline traces, it seems it doesn't.
I need to check some condition and execute some code before/when the view appears, and I'm unable to do it properly.
PS: Does it exist some other alternative event I should use to deal with "This view is becoming visible/focused after you turn the screen on" situation instead of "OnNavigatedTo" ?
Thanks in advance.
In Windows Phone 8.1 Runtime (Store apps) OnNavigatedTo is called only during navigation. It's not called after resuming from suspension - you can read a reference here at MSDN:
before Suspending event, the OnNavigatedFrom event is being called, but when you Resume, the OnNavigatedTo is not called
In your case when you lock the screen, the app is suspended, after you resume OnNavigatedTo is not called. If you look for some events which may be called - take a look at Window.Activated and Window.VisibilityChanged events.
The other case is that when you debug your app, your app won't be suspended, you will need to test it via Lifecycle events tab.
I am building a word game and I want to hide the board when application is suspended?
the code looks fine however it givs a strange behaviour!!,
when I suspend the app nothing will happen but when i resume the application then the board will hide!!
local onSystem = function( event )
if event.type == "applicationSuspend" then
print("suspend")
board_group.alpha = 0
end
end
Runtime:addEventListener( "system", onSystem )
Note: you might wonder how do I know how the application looks when suspended?
the answer is: by pressing the home button twice.
example
SpellTower in normal state
https://dzwonsemrish7.cloudfront.net/items/430k0c0b0y0b413d0b42/Image%202012.11.12%208:08:24%20AM.png?v=4822f549
SpellTower after pressing the home button twice
https://dzwonsemrish7.cloudfront.net/items/280a1y0r2U3W321y1B2z/Image%202012.11.12%208:08:31%20AM.png?v=09c37567
you can see how they are hiding the letters, this is exactly what I want to do for my game, the only difference is i am using Corona SDK
When you do board_group.alpha = 0 you only has set a variable, the result will only take effect after a screen update.
But since the application is suspended... it won't update! So, changing any graphics on applicationSuspend don't work.
I believe the reason is because the application is not considered as suspended. In normal objective c programming it means that applicationWillResignActive is called when the user double clicks on the home button. So what you want to do is to add that code for this part.
Here is a flow of events:
http://www.cocoanetics.com/2010/07/understanding-ios-4-backgrounding-and-delegate-messaging/
Corona seems to have these events:
"applicationStart" occurs when the application is launched and all code
in main.lua is executed.
"applicationExit" occurs when the user quits the application.
"applicationSuspend" occurs when the device needs to suspend the application such as during a phone call or if the phone goes to sleep
from inactivity. In the simulator, this corresponds to the simulator
running in the background. During suspension, no events (not even
enterFrame events) are sent to the application while suspended, so if
you have code that depends on time, you should account for the time
lost to an application being suspended.
"applicationResume" occurs when the application resumes after a suspend. On the phone, this occurs if the application was suspended
because of a phone call. On the simulator, this occurs when the simulator was in the background and now is the foreground application.
So my guess is that you have to implement it outside of the corona API.
According to the corona documents you can implement them in the delegate:
You can intercept UIApplicationDelegate events via your implementation
of the CoronaDelegate protocol.
This protocol conforms to the UIApplicationDelegate protocol. Corona's
internal delegate will call your protocol's method if it is
implemented.
Please keep in mind the following:
Methods that Apple has deprecated will be ignored.
In most cases, your class' version will be invoked after Corona's corresponding version of the UIApplicationDelegate method. There is one situation in which your version will be called before.
In situations where the app is about to suspend or go to the background, your method will be called before Corona's version, e.g.
applicationWillResignActive: and applicationDidEnterBackground:.
http://docs.coronalabs.com/native/enterprise/ios/CoronaDelegate.html
But this is just a guess. Hope it helps!
Edit:
I was thinking, something really simple you could do is catch it outside and present a "pause" screen, then just hide it when the application enters foreground.
So if you can't do that (for now), one other option is to save application state when the application is about to terminate, and then set UIApplicationExitsOnSuspend = true in your plist file. This will cause the application to exit instead of suspending, which will avoid any screenshots, effectively "hiding" the board, etc. The downfall is, the app will have to read the session state when it launches again... this is only useful if your application can be designed to actually exit without losing your state, and is quite honestly, a little extreme. That said, it may be the only way to effectively do what you're trying to do.
Other ideas would be to see if you can add a large black layer to the screen, even though the application is suspending; perhaps this will somehow trigger an internal screen update by natively setting setNeedsDisplay. Also, instead of modifying the alpha, you might consider temporarily removing all of your layers and see if that has a similar effect.
on gwtphonegap 1.7.0.0 (iPhone) i use the geolocation service to get the user's position only once in the beginning on the application
GeolocationOptions options = new GeolocationOptions();
options.setMaximumAge(1000);
options.setEnableHighAccuracy(true);
phoneGap.getGeolocation().getCurrentPosition(callback, options);
the call is made only once in the beginning and no update of the position is needed afterwards.
The problem is that when I run my application on iPhone, the GPS indicator on the status bar stays on all the time, even after I get the correct position.
This may cause a useless battery usage.
Is there a way to tell the Geolocation service to stop after it gets the position?
It seems like we are missing the routines from the gwt phonegap implementation. I just rechecked and they are not part of the docs.
I just posted an issue with the gwt-phonegap project: http://code.google.com/p/gwt-phonegap/issues/detail?id=57
As a workaround you can drop to jsni and call the start / stop method directly.
The underlying phonegap library seems to have start() and stop() methods. You may have to extend gwtphonegap.
On IOS 5, we now have the notification bar on top to put messages. I have seen that Local Notifications will only happen if the app is in the background (not sure when queued, and / or when the notification is to fire, assume the latter).
Is there any way to put notifications in the notification bar while the app is in the foreground?
From my understanding, your app will be notified of a local notification while the app is running in the application:didReceiveLocalNotification delegate method, but a banner will not be shown at the top of the device screen, not will an entry be put in Notification Center. Your app is notified however, and this is so you can show your own UI for the notification in the app, or choose to ignore it.
Notification Center is only for notifications that you're missed because the app is not in the foreground, and that's why they disappear when the app is opened.
Yes, local notifications work with the simulator. However, make sure you are implementing application:didreceiveLocalNotification in your app delegate if you want to see the nofication while your app is in the foreground (source)
further troubleshooting steps per our conversation in chat and based on the above.
Like i said there are only 2 possibilities of why its not working. placement (in app delegate vs another class) and the application variable. so if it works in the app delegate then im not sure how to resolve that other then making a public method that you can reach from the class you want the notification to come from. probably not the most elegant or proper way but i dont know what else to say.
If its the application variable then make sure you use the same one i posted, application from the applicationfinishloading arguments list vs [[shared application]