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fenix/app/src/main/java/org/mozilla/fenix/components/StateViewModel.kt

36 lines
1.2 KiB
Kotlin

/* This Source Code Form is subject to the terms of the Mozilla Public
License, v. 2.0. If a copy of the MPL was not distributed with this
file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.fenix.components
import androidx.fragment.app.Fragment
import androidx.lifecycle.ViewModel
import androidx.lifecycle.ViewModelProvider
import androidx.lifecycle.ViewModelProviders
import androidx.lifecycle.get
import mozilla.components.lib.state.State
/**
* Generic ViewModel to wrap a State object for state restoration
*/
@Suppress("UNCHECKED_CAST")
class StateViewModel<T : State>(initialState: T) : ViewModel() {
var state: T = initialState
private set(value) { field = value }
fun update(state: T) { this.state = state }
companion object {
fun <S : State> get(fragment: Fragment, initialState: S): StateViewModel<S> {
val factory = object : ViewModelProvider.Factory {
override fun <T : ViewModel?> create(modelClass: Class<T>): T {
return StateViewModel(initialState) as T
}
}
return ViewModelProviders.of(fragment, factory).get()
}
}
}