Menu.kt revision 0001cfe5a8cb932c79bca4071e1908a9ad20ea83 
1/*
2 * Copyright (C) 2018 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *       http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17@file:Suppress("NOTHING_TO_INLINE")
18
19package androidx.core.view
20
21import android.view.Menu
22import android.view.MenuItem
23
24/**
25 * Returns the menu at [index].
26 *
27 * @throws IndexOutOfBoundsException if index is less than 0 or greater than or equal to the count.
28 */
29inline operator fun Menu.get(index: Int): MenuItem = getItem(index)
30
31/** Returns `true` if [item] is found in this menu. */
32operator fun Menu.contains(item: MenuItem): Boolean {
33    @Suppress("LoopToCallChain")
34    for (index in 0 until size) {
35        if (getItem(index) == item) {
36            return true
37        }
38    }
39    return false
40}
41
42/** Removes [item] from this menu. */
43inline operator fun Menu.minusAssign(item: MenuItem) = removeItem(item.itemId)
44
45/** Returns the number of items in this menu. */
46inline val Menu.size get() = size()
47
48/** Returns true if this menu contains no items. */
49inline fun Menu.isEmpty() = size() == 0
50
51/** Returns true if this menu contains one or more items. */
52inline fun Menu.isNotEmpty() = size() != 0
53
54/** Performs the given action on each item in this menu. */
55inline fun Menu.forEach(action: (item: MenuItem) -> Unit) {
56    for (index in 0 until size()) {
57        action(getItem(index))
58    }
59}
60
61/** Performs the given action on each item in this menu, providing its sequential index. */
62inline fun Menu.forEachIndexed(action: (index: Int, item: MenuItem) -> Unit) {
63    for (index in 0 until size()) {
64        action(index, getItem(index))
65    }
66}
67
68/** Returns a [MutableIterator] over the items in this menu. */
69operator fun Menu.iterator() = object : MutableIterator<MenuItem> {
70    private var index = 0
71    override fun hasNext() = index < size()
72    override fun next() = getItem(index++) ?: throw IndexOutOfBoundsException()
73    override fun remove() = removeItem(--index)
74}
75
76/** Returns a [Sequence] over the items in this menu. */
77val Menu.children: Sequence<MenuItem>
78    get() = object : Sequence<MenuItem> {
79        override fun iterator() = this@children.iterator()
80    }
81