I'm developing a libGDX game for Android and iOS (MobiDevelop's RoboVM fork). Android works perfectly, but I have a issue on iOS. When the iPhone home button is pressed to leave the game, and I launch the game again by tapping on icon, the game does not resume from where it was paused, but instead restarts, which means the loading screen is displayed, all assets are reloaded, and the main menu appears. Like a fresh/new start of the app. I do not have any specific configuration for the iOS module in my libgdx project and am using what was pregenerated.
Is it possible to tell iOS that I do not want to kill the process? I want to switch to pause/sleeping mode only.
I found a reason of this problem. I tested it on the real device, therefore I was unable to see a logs. When I switch to simulator and look at the logs, I found a NullPointerException. This was a cause of application crash. When I fix this bug, everything works as I expected. After iPhone home button is pressed, pause() method of com.badlogic.gdx.Screen is called and after rerun the game, it continues from exactly where it stops / pauses.
I learned a lesson: make a tests on simulator at first :-)
While I am entirely unfamiliar with libGDX, I can tell you that except for a few very specific cases (VOIP etc.), you cannot control what iOS does with your app when the home button gets pressed.
Furthermore, it is the responsibility of the developer to save the app's state when the app leaves the foreground since this is not something that is or can be handled automatically in a performant way.
Related
This Xamarin.ios app on iPhone must have no splash and no display whatsoever and must leave previous app displayed.
Is is launched by an Objective-C app and it only runs for a short time and then ends itself, leaving screen of the ObjC app always displayed
I need the app that launched it to remain in focus.
USAGE STEPS...
I open the ObjC app, which has command buttons
I press button that starts my Xamarin.ios app which should have no display at all
ObjC app button menu remains displayed
Xamarin.ios app runs and then ends itself
ObjC app button menu remains
Please help -- am under the "time gun" .
This is not possible on iOS - if it makes it easier for you you could have whole the time in this world (and not being under the "time gun") and could not solve it unless Apple changes something in future iOS releases which is unlikely.
The closest you could get to it is to record the screenshot of ObjC app before it launches Xamarin.iOS app, send it some way to Xamarin app (the best way would be if they could be the same App Group), put empty splash screen and ensure that it displays just a split of the second and then display your screenshot in the Xamarin app and do whatever you want to do.
Is the iPhone "device Home button" (circle button that is part of the hardware at bottom center) the standard way that users exit an iPhone app?
I don't have an actual iPhone device yet (looking for the iPhone6 to come down in price a bit), am just working with Xcode simulators. When I run my iPhone Swift apps, they are always in full screen mode.
On Android, there are a few navigation buttons built into the OS that appear at the bottom of the screen - Back, Home, Open Apps. And in that OS you can give a directive to exit full screen to reveal those OS buttons.. which then allows the user to easily exit the app if they'd like to.
In looking at the iPhone apps on the simulator, I notice they don't have this kind of UX.
What are the best practices around iPhone users
A. Sending an app to the background ?
B. Quitting/Closing an app ?
To send an app to the background, hitting the home button is sufficient.
To quit an app, tapping the home button twice shows you all the open apps; you can then swipe an app to "kill" (terminate) it.
However, here is a recent post by the excellent John Gruber explaining why killing an app should only be a last resort: https://daringfireball.net/2017/07/you_should_not_force_quit_apps
Note: on the iPhone Simulator, the command-shift-H key combo is equivalent to hitting the home button.
To send an app to the background:
Press the Home button.
To "quit" or "close" an app:
Press the Home button.
That's all the UX expected of an iOS app... and none if it is actually provided by your app. iOS manages it for you; you just have to deal with your app's lifecycle methods to respond to the user leaving and re-entering your app.
iOS doesn't expect users to know or care about the difference between "background" and "closed/quit" in most cases. You enter an app, you leave an app, that's it.
And the way iOS works under the hood, there is no difference in most cases — when you leave an app, it's not "running in the background", it's "frozen" or "suspended": that is, in memory but not running. That way the OS can get it usable again near-instantly if the user comes back, or instantly reclaim that memory if another process needs it.
The user can also invoke the multitasking UI (double click home button, or in iOS 11 on iPad swipe up from bottom edge) and swipe an app away, but this is equivalent to the "kill" or "force quit" actions seen in other operating systems — it's primarily for situations where an app is misbehaving. This isn't part of your app's UX either; it's also provided by iOS.
As noted in the Daring Fireball post linked from #TimKokesh's answer, there are some circumstances where an app "in the background" isn't "frozen" but has some limited ability to run, the Settings app has UI to help the user keep tabs on what are using (and abusing) that ability, and those are some of the only cases where it's reasonable for a user to "force quit" apps.
If you want to have a real iPhone look-alike simulator on your development environment, yes it's available with New Xcode-9/Beta version. It shows real hardware buttons(volume, lock, home buttons) which you can press and feel like a real device. If you are interested you can download it from here
On other Xcode environments, you can go to home screen by pressing the keys: Cmd + Shift + H
We're developing a web app that extensively uses Cavas 2D for some demos, and is successfully running on both iOS and Android devices. Recently we've added stand-alone mode for iOS devices, so user has to "Add-To-Home-Screen" and run it using screen icon, just like regular app.
What happens recently is that after 10-12 times we start the web app on iPhone4:
Status bar (initially set to 'black') suddenly turns white and we cannot exit Safari (by pressing home button).
If we try to make screen shot (home + power button), shutter sound is played as if screen shot was taken and saved.
If we try to lock the device (power button), screen turns black, but no action after that can bring unlock-screen or any screen for that matter - display remains black.
We can only do reset by pressing home + power for 10 seconds after this point.
If we do not lock the device, web app continuously work with no issues at all, it does not crash, but cannot exit it (double click on home button also has no result).
Has anyone experienced this with their web apps?
Any guidance in how to debug this would be highly appreciated. We've tried using Safari on OSX, connect iPhone to it and use Develop -> iPhone menu but no luck so far.
Thanks in advance!
I would start trying to debug by running XCode with the iPhone connected to the computer.
In XCode open "Organizer" and go to the tab "Devices".
You should see your device there, from which you can view the iOS console. That might be able to tell you what is going wrong with the phone stops responding.
I don't think you have to put the phone in development mode (or be a paid developer) to see the iOS console.
I'm creating a new app. Very, very initial stages (i.e., it literally has no custom code yet). All I've done so far is a basic implementation of Urban Airship's libraries.
Sometimes (about 50% of the time?), when I push the app to my device, the following occurs:
App doesn't load on device
Xcode reports "failed to get task for process"
Device exhibits odd behavior.
"Odd behavior" includes:
Device wallpaper disappears and is replaced with an all black background.
Tapping on any icons gives them a pressed/shadowed look, but nothing happens.
Tapping on the icon again sets it back to its normal state. Again, nothing else.
Pressing home button does nothing.
Pressing lock button will lock device, but no attempt to unlock the device (home button or lock/unlock button) has no effect.
Attempting to use Siri gives the initial sound, but nothing further.
Hard rebooting the device gets it functional again. There doesn't seem to be a pattern to when this "bug" appears.
Has anyone else encountered this "bug"?
Currently working on an application and when run on the simulator or device behaves normally. When you close and reopen the application is behaving strangely.
For example I want to upload the application on the device (iPad), the first run everything is proceeding normally, then I close the application and it is open in the background and behaves strangely, cells no longer have same order.
If you delete the application and run it again after the device from Xcode everything returns to normal.
I tried both ways: Release and Debug.
I checked the code and did deallocate.
Can someone help me with more advice? Thanks in advance!
I suppose you mean pressing the Home button when saying "close". iOS transforms your app in a special suspended state and it seems you don't restore from it correctly. iOS sends a applicationWillEnterForeground notification when your app is being restored from the suspended state and you may need to behave differently than app being launched the first time.
Here you can find more info about this method.