NavHost.kt
/*
* Copyright 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.navigation
import androidx.annotation.IdRes
/**
* A host is a single context or container for navigation via a [NavController].
*
* It is strongly recommended to construct the nav controller by instantiating a
* [NavHostController], which offers additional APIs specifically for a NavHost.
* The NavHostController should still only be externally accessible as a [NavController],
* rather than directly exposing it as a [NavHostController].
*
* Navigation hosts must:
*
* * Handle [saving][NavController.saveState] and
* [restoring][NavController.restoreState] their controller's state
* * Call [Navigation.setViewNavController] on their root view
* * Route system Back button events to the NavController either by manually calling
* [NavController.popBackStack] or by calling
* [NavHostController.setOnBackPressedDispatcher]
* when constructing the NavController.
*
* Optionally, a navigation host should consider calling:
*
* * Call [NavHostController.setLifecycleOwner] to associate the
* NavController with a specific Lifecycle.
* * Call [NavHostController.setViewModelStore] to enable usage of
* [NavController.getViewModelStoreOwner] and navigation graph scoped ViewModels.
*/
public interface NavHost {
/**
* The [navigation controller][NavController] for this navigation host.
*/
public val navController: NavController
}
/**
* Construct a new [NavGraph]
*/
@Suppress("Deprecation")
@Deprecated(
"Use routes to create your NavGraph instead",
ReplaceWith(
"createGraph(startDestination = startDestination.toString(), route = id.toString()) " +
"{ builder.invoke() }"
)
)
public inline fun NavHost.createGraph(
@IdRes id: Int = 0,
@IdRes startDestination: Int,
builder: NavGraphBuilder.() -> Unit
): NavGraph = navController.createGraph(id, startDestination, builder)
/**
* Construct a new [NavGraph]
*/
public inline fun NavHost.createGraph(
startDestination: String,
route: String? = null,
builder: NavGraphBuilder.() -> Unit
): NavGraph = navController.createGraph(startDestination, route, builder)