FragmentNavArgsLazy.kt
/*
* Copyright 2019 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.fragment
import androidx.annotation.MainThread
import androidx.fragment.app.Fragment
import androidx.navigation.NavArgs
import androidx.navigation.NavArgsLazy
/**
* Returns a [Lazy] delegate to access the Fragment's arguments as an [Args] instance.
*
* It is strongly recommended that this method only be used when the Fragment is created
* by [androidx.navigation.NavController.navigate] with the corresponding
* [androidx.navigation.NavDirections] object, which ensures that the required
* arguments are present.
*
* ```
* class MyFragment : Fragment() {
* val args: MyFragmentArgs by navArgs()
* }
* ```
*
* This property can be accessed only after the Fragment's constructor.
*/
@MainThread
public inline fun <reified Args : NavArgs> Fragment.navArgs(): NavArgsLazy<Args> =
NavArgsLazy(Args::class) {
arguments ?: throw IllegalStateException("Fragment $this has null arguments")
}