Manually clearing an Android ViewModel?

Question

Edit: This question is a bit out of date now that Google has given us the ability to scope ViewModel to navigation graphs. The better approach (rather

Answer 1

It seems like it has been already solved in the latest architecture components version.

ViewModelProvider has a following constructor:

    /**
 * Creates {@code ViewModelProvider}, which will create {@code ViewModels} via the given
 * {@code Factory} and retain them in a store of the given {@code ViewModelStoreOwner}.
 *
 * @param owner   a {@code ViewModelStoreOwner} whose {@link ViewModelStore} will be used to
 *                retain {@code ViewModels}
 * @param factory a {@code Factory} which will be used to instantiate
 *                new {@code ViewModels}
 */
public ViewModelProvider(@NonNull ViewModelStoreOwner owner, @NonNull Factory factory) {
    this(owner.getViewModelStore(), factory);
}

Which, in case of Fragment, would use scoped ViewModelStore.

androidx.fragment.app.Fragment#getViewModelStore

    /**
 * Returns the {@link ViewModelStore} associated with this Fragment
 * 

 * Overriding this method is no longer supported and this method will be made
 * final in a future version of Fragment.
 *
 * @return a {@code ViewModelStore}
 * @throws IllegalStateException if called before the Fragment is attached i.e., before
 * onAttach().
 */
@NonNull
@Override
public ViewModelStore getViewModelStore() {
    if (mFragmentManager == null) {
        throw new IllegalStateException("Can't access ViewModels from detached fragment");
    }
    return mFragmentManager.getViewModelStore(this);
}

androidx.fragment.app.FragmentManagerViewModel#getViewModelStore

    @NonNull
ViewModelStore getViewModelStore(@NonNull Fragment f) {
    ViewModelStore viewModelStore = mViewModelStores.get(f.mWho);
    if (viewModelStore == null) {
        viewModelStore = new ViewModelStore();
        mViewModelStores.put(f.mWho, viewModelStore);
    }
    return viewModelStore;
}