Android Navigation Architecture: crash while on Don't keep Activities option

Question

I'm currently using Android Arch Navigation (1.0.0-alpha06) in one of my projects. But from time to time I'm getting the same crash in my Crashlytics:

java.lang.RuntimeException: Unable to start activity ComponentInfo{*.*.*.MainActivity}: android.view.InflateException: Binary XML file line #29: Binary XML file line #29: Error inflating class fragment
Caused by: android.view.InflateException: Binary XML file line #29: Binary XML file line #29: Error inflating class fragment
Caused by: android.view.InflateException: Binary XML file line #29: Error inflating class fragment
Caused by: java.lang.RuntimeException: Parcel android.os.Parcel@1e9584c: Unmarshalling unknown type code 7274595 at offset 516

So after digging why I was having multiple crashes on my MainActivity I set my device to don't keep activities (developer options). And Bam! every time I send my app to the background and come back the app crashes.

I don't have anything set on onSaveInstanceState/onRestoreInstanceState methods. So I don't know where to look at.

This happens with or without proguard enabled (I test it with both debug and release version), so I can rule out a missing proguard rule.

Other info that could help: My app is using android.arch libraries (MVVM).

Edit: I don't have access to the fragment manager perse, the Navigation Library is the one in charge of the fragments, so any other error regarding fragments inflation is not related

Possible duplicate of [Error inflating class fragment](https://stackoverflow.com/questions/6424853/error-inflating-class-fragment) — TheWanderer, Oct 24 '18 at 23:55
Do you have any classes that implement Parcelable in your app? — Ben P., Nov 02 '18 at 18:46
I have a couple of Data Class that uses Kotlin Parcelize; but I'm not using them in `onSaveInstanceState/onRestoreInstanceState`. The crash happens even when I removed those methods from my main activity and fragments... — vicmns, Nov 02 '18 at 23:21

score 0 · Accepted Answer · answered Nov 19 '18 at 17:47

OK I finally found the reason of the crash... It was one custom View Library that I was using that I wasn't managing correctly it's own Instance restore logic.

I found out that the crash was only happening in only two sections of the app, that pin point me where could be the problem.

In the end it was more a problem of not having a good stack trace to look where the problem arisen...

score -2 · Answer 2 · answered Oct 25 '18 at 00:25

Keep in mind Android will still do some save instance state work unless you override the methods in your activities and fragments to do nothing.

  @Override
  protected void onSaveInstanceState(Bundle outState) {
    // don't restore state
  }

In many cases we do this due to the many strange errors otherwise. The implication is that if your app is ejected from memory, it will 100% start fresh the next time it is accessed.

Android Navigation Architecture: crash while on Don't keep Activities option

2 Answers2