EDIT:
So this post was about how to fast load the Android OS to have my application restart a certain way when I call it from background with the restart path, in order to debug an occasional crash on restart from background
I provide below what I have understand/guess about this topic with no guarantee at all
I saw 3 states when the application is in the background:
the application was 'just' send to background and when you call it back, it reappears effortless (all is still in memory)
The app has spent quite time in background and/or the android OS has been stressed enough, for me, starting heavy game (eufloria, browsing one thousand pictures literally, looking at groupon & Gmail did the trick). In this case, it is call back from background and the OS tries to bring the last view to the front and call onRestoreSavedInstance().
Too much time in background, or crash, or huge loads... Anyway, your application restart totally when called from background (onRestoreSavedInstance() is not called at all, but the onCreate and Cie without a savedinstance Bundle).
The trick is to save whatever you think might been deleted in case 2 in onSavedInstance() and retrieve it in onRestoreSavedInstance().
But you have to call these saved variables, attributes, parameters AFTER the onStart() methods (of your fragment sure, activity maybe). This is mandatory because the onRestoreSavedInstance() method is called pretty late in the process: after Activity's onStart(). Cf google documentation on this:
Instead of restoring the state during onCreate() you may choose to implement onRestoreInstanceState(), which the system calls after the onStart() method. The system calls onRestoreInstanceState() only if there is a saved state to restore, so you do not need to check whether the Bundle is null:
So you cannot refer to anything before the onResume() method of your fragment due to the relationship between fragment and activity life-cycle: http://www.linuxforu.com/2011/05/android-fragments-api/
There it is, eventual corrector welcome :)
Thx to david
/****** EDIT fin *****/
The application I have to upgraded (helping friends with their start-up) crashed when coming back from background if it is in background for a sufficient time. It is okay if:
- I kill it from App manager
- I kill it from long press on home button
- I call it back after using several others applications (eufloria, temple run 2, gmail, endomondo)
- all cases I have found on the internet or think of it.
The only way it crashed is coming for background after such time. This issue has been also reported by two customers.
I have read several posts on these subjects and the Google documentation, especially this one from /u/CommonsWare
How to emulate unloading of a background application by Android OS?
But also these
How do you simulate low memory in the Android emulator?
https://groups.google.com/forum/?fromgroups#!topic/android-platform/nifVOvknFsU
I really wish some help even if it is not very critical in itself.
*Why it crashed ONLY after long time (one hours) and/or over-applications usage if killing the app is done the same way as CommonsWare said? Or the crashes are linked to other issues?
*How do you, developers, simulate long time breaks to test that? I need to reproduce this crash if I hope to solve it. It might be an issue of singleton, I saw people talking about it.
I would really appreciate wisdom and guidance !
EDIT:
THere it's the logcat of the crash
06-10 16:08:32.178: I/ActivityThread(26487): Pub com.snapcar.rider: com.snapcar.rider.provider.SCProvider
06-10 16:08:32.298: D/dalvikvm(26487): GC_CONCURRENT freed 255K, 10% free 12336K/13703K, paused 12ms+1ms, total 27ms
06-10 16:08:32.393: V/Localytics(26487): Opening new session
06-10 16:08:32.423: D/dalvikvm(26487): GC_CONCURRENT freed 219K, 10% free 12650K/13959K, paused 1ms+2ms, total 27ms
06-10 16:08:32.423: D/dalvikvm(26487): WAIT_FOR_CONCURRENT_GC blocked 14ms
06-10 16:08:32.423: W/CursorWrapperInner(26487): Cursor finalized without prior close()
06-10 16:08:32.448: D/SC - Auth(26487): Auth-instantiating AuthManager...
06-10 16:08:32.453: D/SC - BookingManager(26487): BookingManager-instantiating BookingManager...
06-10 16:08:32.518: D/SC - WebServiceManager(26487): WebServiceManager-ws type: preprod
06-10 16:08:32.518: D/SC - OtherUtils(26487): OtherUtils-language:fr
06-10 16:08:32.523: E/SC - SCMainActivity(26487): savedInstanceState != null, the application is RE-created
06-10 16:08:32.543: D/dalvikvm(26487): GC_CONCURRENT freed 226K, 10% free 12913K/14215K, paused 11ms+14ms, total 38ms
06-10 16:08:32.628: D/dalvikvm(26487): GC_CONCURRENT freed 145K, 9% free 13307K/14535K, paused 2ms+2ms, total 20ms
06-10 16:08:32.673: D/AndroidRuntime(26487): Shutting down VM
06-10 16:08:32.673: W/dalvikvm(26487): threadid=1: thread exiting with uncaught exception (group=0x40fd82a0)
06-10 16:08:32.678: E/AndroidRuntime(26487): FATAL EXCEPTION: main
06-10 16:08:32.678: E/AndroidRuntime(26487): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.snapcar.rider/com.snapcar.rider.SCMainActivity}: java.lang.NullPointerException
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.app.ActivityThread.access$600(ActivityThread.java:140)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.os.Handler.dispatchMessage(Handler.java:99)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.os.Looper.loop(Looper.java:137)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.app.ActivityThread.main(ActivityThread.java:4898)
06-10 16:08:32.678: E/AndroidRuntime(26487): at java.lang.reflect.Method.invokeNative(Native Method)
06-10 16:08:32.678: E/AndroidRuntime(26487): at java.lang.reflect.Method.invoke(Method.java:511)
06-10 16:08:32.678: E/AndroidRuntime(26487): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
06-10 16:08:32.678: E/AndroidRuntime(26487): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
06-10 16:08:32.678: E/AndroidRuntime(26487): at dalvik.system.NativeStart.main(Native Method)
06-10 16:08:32.678: E/AndroidRuntime(26487): Caused by: java.lang.NullPointerException
06-10 16:08:32.678: E/AndroidRuntime(26487): at com.snapcar.rider.fragment.BookingFormFragment.onCreateView(BookingFormFragment.java:332)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.support.v4.app.FragmentManagerImpl.moveToState(Unknown Source)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.support.v4.app.FragmentManagerImpl.moveToState(Unknown Source)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.support.v4.app.FragmentManagerImpl.moveToState(Unknown Source)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(Unknown Source)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.support.v4.app.FragmentActivity.onStart(Unknown Source)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1167)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.app.Activity.performStart(Activity.java:5216)
06-10 16:08:32.678: E/AndroidRuntime(26487): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2073)
06-10 16:08:32.678: E/AndroidRuntime(26487): ... 11 more
EDIT 2 :
riderID = Integer.parseInt(UserManager.getSharedInstance().getCurrentRider().getUniqueID());
It is the line who crashed this time, I am not sure it is always here. But this (would) confirm what I was pointing to Singleton or values lost? To counter that I was trying this morning to implemented a shared Preferences saving following post and guidelines:
@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
Dbg.e(TAG, "onSavedInstance called");
if (UserManager.getSharedInstance().getCurrentRider() != null ){
Dbg.d(TAG, "We have a current rider");
Rider currentRider = UserManager.getSharedInstance().getCurrentRider();
savedInstanceState.putString(Rider.UNIQUEID_KEY, currentRider.getUniqueID());
(more attributes saved)
The problem is that the fonction onREstoreSavedInstance was not called here. It is like the User Interface is created too fast.
What should I do? Re-define the UI later in the call process of the fragment?
Or is there a more complex issue and this is just one breaking point (if I solve it here, the application will just crash later ?)
thanks for the help and support! It's really give me more courage to keep going on!
EDIT 2: This is my retrieving function:
public void onRestoreInstanceState(Bundle savedInstanceState) {
Dbg.d(TAG,"the application is RE-created & called from onRestoreInstanceState");
// Always call the superclass so it can restore the view hierarchy
super.onRestoreInstanceState(savedInstanceState);
// Restore state members from saved instance
if (UserManager.getSharedInstance().getCurrentRider() == null) {
Rider currentRider = new Rider();
currentRider.setUniqueID(savedInstanceState.getString(Rider.UNIQUEID_KEY));
}}
(more settings)
I just noticed I didn't wrote Override & I did not set the created rider to the UserManager. Thus, the method is called in some other proofs I was doing. I add both now. I retest.
EDIT 3-4 ?
It is the rider that is null:
06-10 17:05:14.248: E/SC - BookingFormFragment(837): it's the CurrentRider that is null !!!
https://stackoverflow.com/questions/17024705
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