NavBackStackEntry.java
/*
* 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;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.lifecycle.ViewModelStore;
import androidx.lifecycle.ViewModelStoreOwner;
import java.util.UUID;
/**
* Representation of an entry in the back stack of a {@link NavController}.
*/
final class NavBackStackEntry implements ViewModelStoreOwner {
private final NavDestination mDestination;
private final Bundle mArgs;
// Internal unique name for this navBackStackEntry;
@NonNull
final UUID mId;
private NavControllerViewModel mNavControllerViewModel;
NavBackStackEntry(@NonNull NavDestination destination, @Nullable Bundle args,
@Nullable NavControllerViewModel navControllerViewModel) {
this(UUID.randomUUID(), destination, args, navControllerViewModel);
}
NavBackStackEntry(@NonNull UUID uuid, @NonNull NavDestination destination,
@Nullable Bundle args, @Nullable NavControllerViewModel navControllerViewModel) {
mId = uuid;
mDestination = destination;
mArgs = args;
mNavControllerViewModel = navControllerViewModel;
}
/**
* Gets the destination associated with this entry
* @return The destination that is currently visible to users
*/
@NonNull
public NavDestination getDestination() {
return mDestination;
}
/**
* Gets the arguments used for this entry
* @return The arguments used when this entry was created
*/
@Nullable
public Bundle getArguments() {
return mArgs;
}
void setNavControllerViewModel(@NonNull NavControllerViewModel navControllerViewModel) {
mNavControllerViewModel = navControllerViewModel;
}
@NonNull
@Override
public ViewModelStore getViewModelStore() {
return mNavControllerViewModel.getViewModelStore(mId);
}
}