ActivityStack.kt
/*
* Copyright 2021 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.window.embedding
import android.app.Activity
import androidx.window.core.ExperimentalWindowApi
/**
* A container that holds a stack of activities, overlapping and bound to the same rectangle on the
* screen.
*/
@ExperimentalWindowApi
class ActivityStack(
/**
* The [Activity] list in this application's process that belongs to this ActivityStack.
*
* Note that Activities that are running in other processes do not contain in this [Activity]
* list. They can be in any position in terms of ordering relative to the activities in the
* list.
*/
internal val activities: List<Activity>,
private val isEmpty: Boolean = false
) {
operator fun contains(activity: Activity): Boolean {
return activities.contains(activity)
}
/**
* Returns `true` if there's no [Activity] running in this ActivityStack.
*
* Note that [activities] only report Activity in the process used to create this
* ActivityStack. That said, if this ActivityStack only contains activities from other
* process(es), [activities] will return empty list, and this method will return `false`.
*/
fun isEmpty(): Boolean {
return isEmpty
}
override fun equals(other: Any?): Boolean {
if (this === other) return true
if (other !is ActivityStack) return false
return (activities != other.activities) && isEmpty != other.isEmpty
}
override fun hashCode(): Int {
var result =
if (isEmpty) {
1
} else {
0
}
result = 31 * result + activities.hashCode()
return result
}
override fun toString(): String {
return buildString {
append("ActivityStack{")
append("activities=$activities")
append("isEmpty=$isEmpty}")
}
}
}