Android ViewModel recreated on screen rotation

Question

I found a case when architecture components ViewModel isn\'t retained - in short it goes as follows:

1. Activity is started and ViewModel in

Answer 1

Yes @tomwyr, this was a bug from an android framework. Bug details

The fix is available in 28.0.0-alpha3 and AndroidX 1.0.0-alpha3

But if you don't want to update to above versions now itself, Then you can solve like this (I know this is a bad solution but I didn't see any other good way)

In your activity override onDestroy method and save all the required fields to local variables before calling super.onDestroy. Now call super.onDestroy then Initialize your ViewModel again and assign the required fields back to your new instance of ViewModel

about isFinishing

Below code is in Kotlin:

override fun onDestroy() {
     val oldViewModel = obtainViewModel()

     if (!isFinishing) { //isFinishing will be false in case of orientation change

          val requiredFieldValue = oldViewModel.getRequiredFieldValue()

          super.onDestroy

         val newViewModel = obtainViewModel()

         if (newViewModel != oldViewModel) { //View Model has been destroyed
              newViewModel.setRequiredFieldValue(requiredFieldValue)
          }
      } else {
         super.onDestroy
      }
 }

private fun obtainViewModel(): SampleViewModel {
      return ViewModelProviders.of(this).get(SampleViewModel::class.java)
}