Jetpack Saved State for ViewModel: Getting Started | raywenderlich.com

🎓 Courses & Articles
1

In this tutorial, you’ll learn how to used saved state library to preserve the state of an android application and thus improving the user experience.

This is a companion discussion topic for the original entry at https://www.raywenderlich.com/5212210-jetpack-saved-state-for-viewmodel-getting-started
2

It was good. There are some improvements that can assist. to make it more concise and better.

  1. With the help of KTX we can define ViewModel using by viewModels()
    viewModel = ViewModelProviders.of(this, SavedStateViewModelFactory(this)).get(ShoppingListViewModel::class.java)

  2. getItems().value!!.add(itemName) // it also don’t notify the observers because of addition, so it make it more elegant it needs to be written in a way that observers can notify properly
    May be creating separate list and then updating the livedata by that list

it would be great if we can remove non-null assertions

  1. If we don’t have items it’s good to hide the recyclerview rather than rendering it with nothing

private fun loadShoppingLists() {
// 2
viewModel.loadShoppingList()
// 3
viewModel.getItems().observe(this, Observer<ArrayList> {
shoppingListAdapter = ShoppingListAdapter(viewModel.getItems().value ?: arrayListOf())
recyclerView.adapter = shoppingListAdapter
shoppingListAdapter.notifyDataSetChanged()
// simething like this
items?.apply{
shoppingListAdapter = ShoppingListAdapter(this)
recyclerView.adapter = shoppingListAdapter
shoppingListAdapter.notifyDataSetChanged()
}

})

}

Thanks

1 Like
3

Hi! Not sure if it’s just me but the Final project doesn’t work… the new items aren’t saved after restarting the app after process death.

4

@droidchef Can you please help with this when you get a chance? Thank you - much appreciated! :]

5

Hi @karlj

What is the API Version of your emulator?
This will only work on Android Version P and above.

Can you try and confirm if the problem still persists?

6

Hi @droidchef, I’m encountering this issue in Android 10 / API 29.

7

@karlj Do you still have issues with this?