How to share view models between fragments using Google's GithubBrowserSample approach?

Question

I am very new using Android architecture components, so I decided to base my application using GithubBrowserSample to achieve many of my use cases. But i have the problem that i don´t know what is the correct way to share viewmodels between fragments with this approach.

I want to share the view model because i have a fragment with a viewpager with 2 fragments that need to observe data of the parent fragment view model

I used this before to achieve it, based on google's documentation

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    model = activity?.run {
        ViewModelProviders.of(this)[SharedViewModel::class.java]
    } ?: throw Exception("Invalid Activity")
}

but with the lifecycle-extensions:2.2.0-alpha03 seems to be deprecated

In GithubBrowserSample they have something like this to create an instance of a view model, but with this it seems to be a different instance every time

@Inject
lateinit var viewModelFactory: ViewModelProvider.Factory

private val userViewModel: UserViewModel by viewModels {
    viewModelFactory
}

And i don't know where to pass the activity scope or if I should pass it.

I tried something like this

@Inject
lateinit var viewModelFactory: ViewModelProvider.Factory

private lateinit var myViewModel: MyViewModel

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    myViewModel = activity?.run {
        ViewModelProvider(this, viewModelFactory).get(MyViewModel::class.java)
    } ?: throw Exception("Invalid Activity")
}

but im getting

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    model = activity?.run {
        ViewModelProviders.of(this)[SharedViewModel::class.java]
    } ?: throw Exception("Invalid Activity")
}

希望您能对我有所帮助，我对此有些迷惑，对不起，如果我的英语不好

Answer 1

by viewModels()提供一个范围为单个Fragment的ViewModel。有一个单独的by activityViewModels()范围将ViewModel范围限定到您的Activity。

但是，直接替换ViewModelProviders.of(this)很简单ViewModelProvider(this)-您不需要切换到by viewModels()或by activityViewModels()使用lifecycle-extensions:2.2.0-alpha03